外文翻译--注射成型机液压系统

中英文对照外文翻译文献(文档含英文原文和中文翻译)原文：FEATURE-BASED COMPONENT MODELS FOR VIRTUALPROTOTYPING OF HYDRAULIC SYSTERMAbstract:This paper proposes a feature-based approach for the virtual prototyping of hydraulic systems. It presents a framework which allows the designer to develop a virtual hydraulic system prototype in a more intuitive manner, i.e. through assembly of virtual components with engineering data. The approach is based on identifying the data required for the development of the virtual prototypes, and separating the information into behaviour, structural, and product attributes. Suitable representations of these attributes are presented, and the framework for the feature-based virtual prototyping approach is established,based on the hierarchical structure of components in a hydraulic system. The proposed framework not only provides a precise model of the hydraulic prototype but also offers the possibility of designing variation classes of prototypes whose members are derived by changing certain virtual components with different features.Key words: Computer-aided engineering; Fluid power systems;Virtualprototyping1.IntroductionHydraulic system design can be viewed as a function-to-form transformation process that maps an explicit set of requirements into a physical realisable fluid power system. The process involves three main stages: the functional specification stage,the configuration design stage, and the prototyping stage.The format for the description of the design in each stage is different.The functional specification stage constitutes the initial design work. The objective is to map the design requirements. To achieve this, the design problems are specified Correspondence and offprint requests to: Dr S. C. Fok, Schoool of Mechanical and Production Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798. The designer must identify the performance attributes, which can include pressure, force, speed, and flowrate, with the required properties such as size, cost, safety and operating sequence. performance requirements for each attribute. In this stage, the design is abstracted in terms of the performance attributes with associated values.The objective of the configuration design stage is to synthesise a hydraulic circuit that performs the required functions conforming to the performance standards within defined constraints. A typical hydraulic system is made up of many subsystems. The smallest building block in a subsystem is the standard hydraulic component (such as valves, cylinders,pumps, etc.). Each type of standard component serves a specific elemental function. The design effort in the configuration design stage is fundamentally a search for a set of optimal arrangements of standard components (i.e. hydraulic circuit) to fulfil the functional requirements of the system. Based on this framework, the designers would normally decompose the overall system functions in terms of subfunctions. This will partition the search space and confine the search for smaller hydraulic subcircuits to perform the subfunctions.Computers are often used to support the configuration design process. For example, Kota and Lee devised a graph-based strategy to automate the configuration of hydraulic circuits. After the development of the hydraulic circuits, digital simulation tools are often used to study and evaluate these configurations. With these tools, designers can compare the behaviour of different circuits and also analyse the effects when subcircuits are combined. In the configuration design stage, the design is traditionally represented as a circuit drawing using standard icons to symbolise the type of standard component. This is a form of directed graph S(C,E) where the circuit S contains components C in the form of nodes with relations between components denoted by edges E.The prototyping stage is the verification phase of the system design process where the proposed hydraulic circuit from the configuration design stage isdeveloped and evaluated. Physical prototyping aims to build a physical prototype of the hydraulic system 666 S. C. Fok et al. using industrial available components. The process of physical prototyping involves the following: Search for appropriate standard components from different manufacturers. Pre-evaluation and selection of components based on individual component cost, size, and specification, and compatibility factors between components. Procurement and assembly of the selected components.Test and evaluate the physical prototype based on the overall system requirements. Use other components or redesign the circuit (or subcircuits)if necessary.Besides dynamics, the development of the physical prototype must take into consideration other factors including structure,cost, and weight. The dynamics data are used to confirm the fluid power system behaviour whereas the geometric information is used to examine the assembly properties. The development of the physical prototype will provide the actual performance,structure, and cost of the design.The main disadvantage of physical prototyping is that it is very tedious and time consuming to look for a set of suitable combinations of standard components from among so many manufacturers. Although the basic functions of the same types of standard component from different manufacturers do not differ, their dynamics, structural and cost characteristics may not be similar, because of design variation. Hence, for a given hydraulic circuit, different combinations of parts from differentmanufacturers can have implications on the resulting system,in terms of dynamics, structure, and cost. Value engineering can be used at this stage to improve the system design by improving the attributes at the component level. This includes maximizing the performance-to-cost ratio and minimising the size-to-performance ratio. Virtual prototyping can be viewed as a computer-aided design process, which employs modelling and simulating tools to address the broad issues of physical layout, operationalconcept, functional specifications, and dynamics analysis under various operating environments. The main advantage of virtual prototyping is that a hydraulic system prototype can be assembled, analysed, and modified using digital computers without the need for physical components, thus saving lead time and cost.The main requirement of a virtual hydraulic system prototype is to provide the same information as a physical prototype for the designer to make decisions.To achieve this, the virtual prototype must provide suitable and comprehensive representations of different data. Furthermore, transformation from one representation to another should proceed formally. Xiang et al. have reviewed the past and current computer-aided design and prototyping tools for fluid power systems. The work revealed that the current tools could not provide a completerepresentation of the design abstractions at the prototyping stage for design judgement. Most of the tools concentrate on the dynamics behaviour. Vital geometrical and product information that relates to the system prototype consideration and evaluation is frequently missing.To advance the development of computer-aided virtual prototyping tools for fluid power systems, there is a need to address the formal representations of different abstractions of behaviour,structural, and product data along with their integration. This paper focuses on these issues and proposes the formalism of a unified component model and the taxonomy based on the feature-based approach. In Section 2, we discuss the feature- based approach focusing on the key information and their representations required for hydraulic system prototyping. Section 3 presents a formalism of the feature-based model and structure for the development of virtual hydraulic system prototypes.The structure is illustrated with an example. Future work and conclusions are given in Section 4.2. Feature-Based ApproachFeatures can be defined as information sets that refer to aspects of attributes that can be used in reasoning about the design, engineering or manufacturing processes. The concept of using features to integrate CAD/CAPP/CAM is not new and there are many papers on the application of this approach in CIM. In all these applications, the feature model is regarded as the basis whereas design by features is the key for the integration. To develop a feature model, the relevant information concerning the design must be identified and grouped into sets based on the nature of the information. The relevant information should contain sufficient knowledge for activities such as design, analysis, test, documentation, inspection, and assembly, as well as support various administrative and logistic functions. Design by features is the process of building a model of the design using features as primitive entities. The feature model provides the standardisation of relevant data. Through the design by features approach, vital knowledge of the design will be generated and stored. Together, the feature model and the design by features approach will provide the essential information, which can be used, not only for the simultaneous consideration of many different concerns with the design, but also to interface the many activities in the design realisation process, including the life cycle support operations. The main drawback of the feature-based design approach is that the feature model should be properly defined . This can be difficult, as features are sets of knowledge that are application dependent. The organisation of the features can also be application specific. Non-trivial data-management problems could arise if the feature model is not properly defined. To avoid these problems, the type,representation and structure of the features should be resolved prior to using the feature-based design methodology. The main concern when developing afeature model is that it is application-specific. In the domain of virtual prototyping of hydraulic systems, the details of the constituent standard components must be able to be used to describe the overall system. The component features are bearers of knowledge about that part. To create a suitable feature model for hydraulic system design based on the assembly of standard components, the relevant information associated with various standard components must be identified and classified. This definition Feature-Based Component Models 667 of the component feature set can then be extended to encompass the subsystem feature set based on the hierarchical structure between the components in the subsystem. In the same manner, a hierarchical structure for the hydraulic system feature representation would evolve by considering the system as a hierarchy of subsystems.The necessary information required for a proper description of the virtual prototype must be no less than that derived by the designer from a physical prototype for decision making. These data should generally include the shape, weight, performance properties, cost, dimensions, functionality data, etc. Comparison with the physical prototyping process, the information required for each standard component could be separated into three distinct groups: behaviour attributes, structural attributes, and product attributes.2.1 Behaviour AttributesThe behaviour of a hydraulic component can be defined in terms of the dynamics characteristics used to satisfy the functional requirements. Consider a hydraulic cylinder connected to a load. Its function is to transmit a force from the stroke of the piston to the load. The maximum force it can transmit can be used to define the functionality and the behaviour requirements can be specified in terms of the desired load acceleration characteristics. Hence for a hydraulic component, behaviour attributes express functionality and can be reflected in the dynamics characteristics. The designer is responsible for the proper definition of the overall system behaviour characteristics in terms of the desired dynamics. A standard component will have its own behaviour and provide a specific plex functions that cannot be achieved by a single standard component are derived using a combination of components. Hence, the behaviour of the standard component will play an important role as the individual behaviours of components together with their arrangement can alter the overall system function .The behaviour of a standard component can be nonlinear and can be dependent on the operating conditions. When two components are combined, it is possible that their behaviours can interact and produce undesired or unintended characteristics. These unwanted behaviours are assumed to have been resolved during the configuration design stage. The hydraulic circuit used in theprototyping stage is assumed to be realisable and without any undesirable interacting behaviours. This means that the output behaviour of a component will provide the input to the subsequent component.The representation of behaviours for hydraulic systems has been widely investigated. These representations include transfer functions, state-space and bond graphs. Transfer functions (for single-input–single-output systems) and state-space equations (for multiple-input–multiple-output systems) are based on the approximation of the dynamics about a nominal operating condition. The power bond graph model is based on the causal effects that describe the energy transformations in the hydraulic system. This approach is appealing for hydraulic system analysis. The main disadvantage is that the derivation of the dynamics equation in a bond graph of a complicated fluid power system can become very tedious. As a result, recent work has concentrated on the used of artificial intelligence to represent the nonlinear mapping between the input and output data, which can be obtained via experimental work. These nonlinear mappings can be accomplished using artificial neural networks .It is quite natural for a hydraulic system designer to use input–output data to describe the behaviour of a hydraulic component. The configuration design of a hydraulic system is often achieved through steps of function decomposition. To design a hydraulic system, the designer often tries to decompose the functions and their requirements down to the component level.译文：基于原型液压系统特征的机构模型摘要：本文为原型液压系统的设计提出了一种基于特征的方法。

塑料注射成型外文文献翻译、中英文翻译、外文翻译外文翻译原文：Injection MoldingMany different processes are used to transform plastic granules, powders, and liquids into product. The plastic material is in moldable form, and is adaptable to various forming methods. In most cases thermosetting materials require other methods of forming. This is recognized by the fact that thermoplastics are usually heated to a soft state and then reshaped before cooling. Theromosets, on the other hand have not yet been polymerized before processing, and the chemical reaction takes place during the process, usually through heat, a catalyst, or pressure. It is important to remember this concept while studying the plastics manufacturing processes and polymers used.Injection molding is by far the most widely used process of forming thermoplastic materials. It is also one of the oldest. Currently injection molding accounts for 30% of all plastics resin consumption. Since raw material can be converted by a single procedure, injection molding is suitable for mass production of plastics articles and automated one-step production of complex geometries. In most cases, finishing is not necessary. Typical products include toys, automotive parts, household articles, and consumer electronics goods.Since injection molding has a number of interdependent variables, it is a process of considerable complexity. The success of the injection molding operation is dependent not only in the proper setup of the machine hydraulics, barrel temperaturevariations, and changes in material viscosity. Increasing shot-to-shot repeatability of machine variables helps produce parts with tighter tolerance, lowers the level of rejects, and increases product quality (i.e., appearance and serviceability).The principal objective of any molding operation is the manufacture of products: to a specific quality level, in the shortest time, and using repeatable and fully automaticcycle. Molders strive to reduce or eliminate rejected parts in molding production. For injection molding of high precision optical parts, or parts with a high added value such as appliance cases, the payoff of reduced rejects is high.A typical injection molding cycle or sequence consists of five phases;1. Injection or mold filling2. Packing or compression3. Holding4. Cooling5. Part ejectionPlastic granules are fed into the hopper and through an in the injection cylinder where they are carried forward by the rotating screw. The rotation of the screw forces the granules under high pressure against the heated walls of the cylinder causing them to melt. As the pressure building up, the rotating screw is forced backward until enough plastic has accumulated to make the shot. The injection ram (or screw) forces molten plastic from the barrel, through the nozzle, sprue and runner system, and finally into the mold cavities. During injection, the mold cavity is filled volumetrically. When the plastic contacts the cold mold surfaces, it solidifies (freezes) rapidly to produce theskin layer. Since the core remains in the molten state, plastic follows through the core to complete mold filling. Typically, the cavity is filled to 95%~98% during injection. Then the molding process is switched over to the packing phase.Even as the cavity is filled, the molten plastic begins to cool. Since the cooling plastic contracts or shrinks, it gives rise to defects such as sink marks, voids, and dimensional instabilities. To compensate for shrinkage, addition plastic is forced into the cavity. Once the cavity is packed, pressure applied to the melt prevents molten plastic inside the cavity from back flowing out through the gate. The pressure must be applied until the gate solidifies. The process can be divided into two steps (packing and holding) or may be encompassed in one step(holding or second stage). During packing, melt forced into the cavity by the packing pressure compensates for shrinkage. With holding, the pressure merely prevents back flow of the polymer malt.After the holding stage is completed, the cooling phase starts. During, the part is held in the mold for specified period. The duration of the cooling phase depends primarily on the material properties and the part thickness. Typically, the part temperature must cool below the material’s ejection temperature. While cooling the part, the machine plasticates melt for the next cycle.The polymer is subjected to shearing action as well as the condition of the energy from the heater bands. Once the short is made, plastication ceases. This should occur immediately before the end of the cooling phase. Then the mold opens and the part is ejected.When polymers are fabricated into useful articles they are referred to as plastics, rubbers, and fibers. Some polymers, forexample, cotton and wool, occur naturally, but the great majority of commercial products are synthetic in origin. A list of the names of the better known materials would include Bakelite, Dacron, Nylon, Celanese, Orlon, and Styron.Previous to 1930 the use of synthetic polymers was not widespread. However, they should not be classified as new materials for many of them were known in the latter half of the nineteenth century. The failure to develop them during this period was due, in part, to a lack of understanding of their properties, in particular, the problem of the structure of polymers was the subject of much fruitless controversy.Two events of the twentieth century catapulted polymers into a position of worldwide importance. The first of these was the successful commercial production of the plastic now known as Bakelite. Its industrial usefulness was demonstrated in1912 and in the next succeeding years. T oday Bakelite is high on the list of important synthetic products. Before 1912 materials made from cellulose were available, but their manufacture never provided the incentive for new work in the polymer field such as occurred after the advent of Bakelite. The second event was concerned with fundamental studies of the nature polymers by Staudinger in Europe and by Carohers, who worked with the Du Pont company in Delaware. A greater part of the studies were made during the 1920’s. Staudinger’s work was primarily fundamental. Carother’s achievements led t o the development of our present huge plastics industry by causing an awakening of interest in polymer chemistry, an interest which is still strongly apparent today.The Nature of ThermodynamicsThermodynamics is one of the most important areas ofengineering science used to explain how most things work, why some things do not the way that they were intended, and why others things just cannot possibly work at all. It is a key part of the science engineers use to design automotive engines, heat pumps, rocket motors, power stations, gas turbines, air conditioners, super-conducting transmission lines, solar heating systems, etc.Thermodynamics centers about the notions of energy, the idea that energy is conserved is the first low of thermodynamics. It is starting point for the science of thermodynamics is entropy; entropy provides a means for determining if a process is possible.This idea is the basis for the second low of thermodynamics. It also provides the basis for an engineering analysis in which one calculates the maximum amount of useful that can be obtained from a given energy source, or the minimum amount of power input required to do a certain task.A clear understanding of the ideas of entropy is essential for one who needs to use thermodynamics in engineering analysis. Scientists are interested in using thermodynamics to predict and relate the properties of matter; engineers are interested in using this data, together with the basic ideas of energy conservation and entropy production, to analyze the behavior of complex technological systems.There is an example of the sort of system of interest to engineers, a large central power stations. In this particular plant the energy source is petroleum in one of several forms, or sometimes natural gas, and the plant is to convert as much of this energy as possible to electric energy and to send this energy down the transmission line.Simply expressed, the plant does this by boiling water andusing the steam to turn a turbine which turns an electric generator.The simplest such power plants are able to convert only about 25 percent of the fuel energy to electric energy. But this particular plant converts approximately 40 percent;it has been ingeniously designed through careful application of the basic principles of thermodynamics to the hundreds of components in the system.The design engineers who made these calculations used data on the properties of steam developed by physical chemists who in turn used experimental measurements in concert with thermodynamics theory to develop the property data.Plants presently being studied could convert as much as 55 percent of the fuel energy to electric energy, if they indeed perform as predicted by thermodynamics analysis.The rule that the spontaneous flow of heat is always from hotter to cooler objects is a new physical idea. There is noting in the energy conservation principle or in any other law of nature that specifies for us the direction of heat flow. If energy were to flow spontaneously from a block of ice to a surrounding volume of water, this could occur in complete accord with energy conservation. But such a process never happens. This idea is the substance of the second law of thermodynamics.Clear, a refrigerator, which is a physical system used in kitchen refrigerators, freezers, and air-conditioning units must obey not only the first law (energy conservation) but the second law as well.To see why the second law is not violated by a refrigerator, we must be careful in our statement of law. The second law of thermodynamics says, in effect, that heat never flowsspontaneously from a cooler to a hotter object.Or, alternatively, heat can flow from a cooler to a hotter object only as a result of work done by an external agency. We now see the distinction between an everyday spontaneous process, such as the flow of heat from the inside to the outside of a refrigerator.In the water-ice system, the exchange of energy takes place spontaneously and the flow of heat always proceeds from the water to the ice. The water gives up energy and becomes cooler while the ice receives energy and melts.In a refrigerator, on the other hand, the exchange of energy is not spontaneous. Work provided by an external agency is necessary to reverse the natural flow of heat and cool the interior at the expense of further heating the warmer surroundings.译文：塑料注射成型许多不同的加工过程习惯于把塑料颗粒、粉末和液体转化成最终产品。

液压英文文献及翻译液压系统1.绪论液压站称液压泵站，是独立的液压装置。

它是按逐级要求供油。

并控制液压油流方向、压力和流量，适用在主机与液压装置可分离的各种液压机械上面。

用户在购后只要将液压站与主机上执行机构（油缸或油马达）用不同的油管相连，液压机械即实现各种规定的动作与工作循环。

液压站是由集成块、泵装置或阀组合、电气盒、油箱电气盒组合而成。

各个部件功能为：泵装置——上装有电机和油泵，其是液压站的动力源，能将机械能转化为液压油压力能。

阀组合－－其板式阀装在立板上，板后管连接，与集成块的功能相同。

油集成块－－是由液压阀及通道体组装而成。

其对液压油实行压力、方向和流量调节。

箱－－是板焊的半封闭容器，上面还装有滤油网、空气滤清器等，是用来储油与油的冷却及过滤。

电气盒－－分两种型式：一种是设置外接引线的端子板；一种是配置了全套控制电器。

液压站工作原理：电机带动油泵转动，然后泵从油箱中吸油并供油，将机械能转化为液压站压力能，液压油通过集成块（或阀组合）实现方向、压力、流量调节后经过外接管路并至液压机械里的油缸或油马达中，从而控制液动机方向变换、力量的大小及速度的快慢，来推动各种液压机械做功。

(1)液压的发展历程在我国液压（含液力，下同）、气动和密封件工业的发展历程，大致可分成三个阶段，即：在20世纪50年代初到60年代初是起步阶段；60-70年代为专业化生产体系的成长阶段；80-90年代为快速发展阶段。

在其中，液压工业始于50年代初从机床行业生产的仿苏的磨床、拉床、仿形车床等液压传动来起步，液压元件由机床厂里的液压车间生产，自产自用。

在进入60年代后，液压技术应用从机床逐渐推广到农业机械与工程机械等领域，原来附属于主机厂里的液压车间有些独立出来，成为液压件的专业生产厂。

在60年代末、70年代初，随着生产机械化的不断发展，特别是在为第二汽车制造厂等提供了高效、自动化设备的带动下，液压元件制造业出现了不断迅速发展的局面，一批中小企业也开始成为液压件专业制造厂。

附录Hydraulic SystemHydraulic presser drive and air pressure drive hydraulic fluid as the transmission is made according to the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 •Barman Joseph (Joseph Barman, 1749-1814), in London water as a medium to form hydraulic press used in industry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved.After the World War I (1914-1918) ,because of the extensive application of hydraulic transmission, especially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th century, 20 years, only started to enter the formal phase of industrial production. 1925 Vickers (F. Vickers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundation. The early 20th century G • Constantia scofluctuations of the energy carried out by passing theoretical and practical research; in 1910 on the hydraulic trans- mission (hydraulic coupling, hydraulic torque converter, etc.) contributions, so that these two areas of development.The Second World War (1941-1945) period, in the United States 30% of machine tool applications in the hydraulic transmission. It should be noted that the development of hydraulic transmission in Japan than Europe and the United States and other countries fornearly 20 years later. Before and after in 1955, the rapid development of Japan's hydraulic drive, set up in 1956, "Hydraulic Industry." Nearly 20 to 30 years, the development of Japan's fast hydraulic transmission, a world leader.Hydraulic transmission There are many outstanding advantages, it is widely used, such as general industrial use of plastics processing machinery, the pressure of machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flood control and dam gate devices, bed lifts installations, bridges and other manipulation of institutions; speed turbine power plant installations, nuclear power plants, etc.; ship from the deck heavy machinery (winch), the bow doors, bulkhead valve, stern thruster, etc.; special antenna technology giant with control devices, measurement buoys, movements such as rotating stage; military-industrial control devices used in artillery, ship anti- rolling devices, aircraft simulation, aircraft retractable landing gear and rudder control devices and other devices.A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, auxiliary components and hydraulic oil.The role of dynamic components of the original motive fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydra- ulic pump gears are generally pump, vane pump and piston pump.Implementation of components (such as hydraulic cylinders and hydraulic motors) which isthe pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement.Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to the different control functions, hydraulic pressure control valve can be divided into valves, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve.Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars.Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories.The role of the hydraulic system is to help humanity work. Mainly by the implementation of components to rotate or pressure into a reciprocating motion.Hydraulic system and hydraulic power control signal is composed of two parts, the signal control of some parts of the hydraulic power used to drive the control valve movement.Part of the hydraulic power means that the circuit diagram used to show the differentfunctions of the interrelationship between components. Containing the source of hydraulic pump, hydraulic motor and auxiliary components; hydraulic control part contains a variety of control valves, used to control the flow of oil, pressure and direction; operative or hydraulic cylinder with hydraulic motors, according to the actual requirements of their choice.In the analysis and design of the actual task, the general block diagram shows the actual operation of equipment. Hollow arrow indicates the signal flow, while the solid arrows that energy flow.Basic hydraulic circuit of the action sequence - Control components (two four-way valve) and the spring to reset for the implementation of components (double-acting hydraulic cylinder), as well as the extending and retracting the relief valve opened and closed. For the implementation of components and control components, presentations are based on the corresponding circuit diagram symbols, it also introduced ready made circuit diagram symbols.Working principle of the system, you can turn on all circuits to code. If the first implementation of components numbered 0, the control components associated with the identifier is 1. Out with the implementation of components corresponding to the identifier for the even components, then retracting and implementation of components corresponding to the identifier for the odd components. Hydraulic circuit carried out not only to deal with numbers, but also to deal with the actual device ID, in order to detect system failures.DIN ISO1219-2 standard definition of the number of component composition, which includes the following four parts: device ID, circuit ID, component ID and component ID.The entire system if only one device, device number may be omitted.Practice, another way is to code all of the hydraulic system components for numbers at this time, components and component code should be consistent with the list of numbers. This method is particularly applicable to complex hydraulic control system, each control loop are the corresponding number with the systemWith mechanical transmission, electrical transmission compared to the hydraulic drive has the following advantages:1. a variety of hydraulic components can easily and flexibly to layout.2. light weight, small size, small inertia, fast response.3. to facilitate manipulation of control, enabling a wide range of stepless speed regulation (speed range of 2000:1).4. to achieve overload protection automatically.5. the general use of mineral oil as a working medium, the relative motion can be self-lubricating surface, long service life;6. it is easy to achieve linear motion .7. it is easy to achieve the automation of machines, when the joint control of the use of electro-hydraulic, not only can achieve a higher degree of process automation, and remote control can be achieved.The shortcomings of the hydraulic system:1. as a result of the resistance to fluid flow and leakage of the larger, so less efficient. If not handled properly, leakage is not only contaminated sites, but also may cause fire and explosion.2. vulnerable performance as a result of the impact of temperature change, it would be inappropriate in the high or low temperature conditions.3. the manufacture of precision hydraulic components require a higher, more expensive and hence the price.4. due to the leakage of liquid medium and the compressibility and can not be strictly the transmission ratio.5. hydraulic transmission is not easy to find out the reasons for failure; the use and maintenance requirements for a higher level of technology.In the hydraulic system and its system, the sealing device to prevent leakage of the work of media within and outside the dust and the intrusion of foreign bodies. Seals played the role of components, namely seals. Medium will result in leakage of waste, pollution and environmental machinery and even give rise to malfunctioning machinery and equipment for personal accident. Leakage within the hydraulic system will cause a sharp drop in volumetric efficiency, amounting to less than the required pressure, can not even work. Micro-invasive system of dust particles, can cause or exacerbate friction hydraulic component wear, and further lead to leakage.Therefore, seals and sealing device is an important hydraulic equipment components. The reliability of its work and life, is a measure of the hydraulic system an important indicator of good or bad. In addition to the closed space, are the use of seals, so that two adjacent coupling surface of the gap between the need to control the liquid can be sealed following the smallest gap. In the contact seal, pressed into self-seal-style and self-styled self-tight seal (ie, sealed lips) two.The three hydraulic system diseases1. as a result of heat transmission medium (hydraulic oil) in the flow velocity in various parts of the existence of different, resulting in the existence of a liquid within the internal friction of liquids and pipelines at the same time there is friction between the inner wall, which are a result of hydraulic the reasons for the oil temperature. Temperature will lead to increased internal and external leakage, reducing its mechanical efficiency. At the same time as a result of high temperature, hydraulic oil expansion will occur, resulting in increased com- pression, so that action can not be very good control of transmission. Solution: heat is the inherent characteristics of the hydraulic system, not only to minimize eradication. Use a good quality hydraulic oil, hydraulic piping arrangement should be avoided as far as possible the emergence of bend, the use of high-quality pipe and fittings, hydraulic valves, etc.2. the vibration of the vibration of the hydraulic system is also one of its malaise. As a result of hydraulic oil in the pipeline flow of high-speed impact and the control valve to open the closure of the impact of the process are the reasons for the vibration system. Strong vibration control action will cause the system to error, the system will also be some of the more sophisticated equipment error, resulting in system failures. Solutions: hydraulic pipe should be fixed to avoid sharp bends. To avoid frequent changes in flow direction, can not avoid damping measures should be doing a good job. The entire hydraulic system should have a good damping measures, while avoiding the external local oscillator on the system.3. the leakage of the hydraulic system leak into inside and outside the leakage. Leakagerefers to the process with the leak occurred in the system, such as hydraulic piston-cylinder on both sides of the leakage, the control valve spool and valve body, such as between the leakage. Although no internal leakage of hydra- ulic fluid loss, but due to leakage, the control of the established movements may be affected until the cause system failures. Outside means the occurrence of leakage in the system and the leakage between the external environment. Direct leakage of hydraulic oil into the environment, in addition to the system will affect the working environment, not enough pressure will cause the system to trigger a fault. Leakage into the environment of the hydraulic oil was also the danger of fire. Solution: the use of better quality seals to improve the machining accuracy of equipment.Another: the hydraulic system for the three diseases, it was summed up: "fever, with a father拉稀" (This is the summary of the northeast people). Hydraulic system for the lifts, excavators, pumping station, dynamic, crane, and so on large-scale industry, construction, factories, enterprises, as well as elevators, lifting platforms, Deng Axle industry and so on.Hydraulic components will be high-performance, high-quality, high reliability, the system sets the direction of development; to the low power, low noise, vibration, without leakage, as well as pollution control, water-based media applications to adapt to environmental requirements, such as the direction of development; the development of highly integrated high power density, intelligence, macaronis and micro-light mini-hydraulic components; active use of new techniques, new materials and electronics, sensing and other high-tech.---- Hydraulic coupling to high-speed high-power and integrated development of hydraulic transmission equipment, development of water hydraulic coupling medium speedand the field of automotive applications to develop hydraulic reducer, improve product reliability and working hours MTBF; hydraulic torque converter to the development of high-power products, parts and components to improve the manufacturing process technology to improve reliability, promote computer-aided technology, the development of hydraulic torque converter and power shift transmission technology supporting the use of ; Clutch fluid viscosity should increase the quality of products, the formation of bulk to the high-power and high-speed direction.Pneumatic Industry:---- Products to small size, light weight, low power consumption, integrated portfolio of development, the implementation of the various types of components, compact structure, high positioning accuracy of the direction of development; pneumatic components and electronic technology, to the intelligent direction of development; component performance to high-speed, high-frequency, high-response, high-life, high temp- erature, high voltage direction, commonly used oil-free lubrication, application of new technology, new technology and new materials.1. Used high-pressure hydraulic components and the pressure of continuous work to reach 40Mpa, the maximum pressure to achieve instant 48Mpa;2. Diversification of regulation and control;3. To further improve the regulation performance, increase the efficiency of the power train;4. Development and mechanical, hydraulic, power transmission of the composite portfolio adjustment gear;5. Development of energy saving, energy efficient system function;6. To further reduce the noise;7. Application of Hydraulic Cartridge Valves thread technology, compact structure, to reduce the oil spill.液压系统液压传动和气压传动称为流体传动，是根据17世纪帕斯卡提出的液体静压力传动原理而发展起来的一门新兴技术，1795年英国约瑟夫•布拉曼(Joseph Braman,1749-1814)，在伦敦用水作为工作介质，以水压机的形式将其应用于工业上，诞生了世界上第一台水压机。

英文原文Injection molding machineInjection molding machine is plastic machine for short. It uses the thermal physical propertiesof plastics, the material from the hopper into the barrel, is barreled by heating coil heat, so the material will be melted, which is arranged by the external force under the action of the motor driving the rotation of the screw in the barrel. The material in the screw under the action of the screw groove, along the forward delivery and compaction, dual role the material in the heating and shear under gradually plasticizing, melted and homogenized, when the screw rotates, the material in the screw channel friction and shear force, the molten material is pushed to the screw head. At the same time, the screw with backward in the material, the screw head forming material storage space, completing the plasticizing process, then, screw in the injection cylinder piston thrust under the action of high speed, high pressure, in the material storage chamber, the melt through the nozzle to the mold cavity injection, cavity melt after pressing, cooling, solidification, mold in the mold closing mechanism of action next, open mold, and through the ejection device to finalize the design good products fall from the top die.Configuration according to the clamping member and the injection component type has horizontal, vertical, angle type three(1) Horizontal injection molding machine: horizontal injection molding machine is the most common type. Its characteristic is the center line injection assembly and clamping assembly center line of concentric or consistent, also with the parallel to the mounting surface. It has the advantages of low center of gravity, steady work, mold installation, operation and repair, which are convenient, the mold opening big, small occupied space height; but covers an area of large. (2) Vertical injection molding machine: its characteristic is clamping device and injection device of the axis line arrangement and perpendicular to the ground. It also has the advantages of small occupied area, convenient assembly and disassembly of insert mold, easy installation, since the bucket into the material plasticization is evenly, easy to realize automation and machine automation line management. The disadvantage of it is the top product is not easy to fall off automatically, it often needs manual or other method to take out, and is not easy to realize full automatic operation and large products injection; machine height, feeding, inconvenient repair. (3) Angle type injection molding machine: injection device and a molding device axis are arranged vertically. According to the injection assembly center lines are vertical, horizontal and relative position of the vertical and horizontal installation, recumbent points: ① horizontal vertical, injection assembly line and plane parallel, and mold assembly center line and the base of vertical and horizontal, vertical; injection assembly center line and the surface vertical, and die assembly center line and the reference surface. The advantages of angle type injection machine has theadvantages of both horizontal and vertical injection molding machine, special apply to the mold opening side gate asymmetric geometry products.At present, the injection device are common cylinder form and double cylinder form, I plant the injection molding machine is double cylinder form, and is directly driven by a hydraulic motor of screw in injection molding. Because of different manufacturers, different types of machine components are not the same; the following will make a concrete analysis of our factory with machine.The working principle is: the plastic, screw in plastic parts in the drive the main shaft to rotate through the hydraulic motor, spindle end is connected with the screw, and the other end of the hydraulic motor key connection, screw rotation, plasticity and melt classified pushed to the storage chamber cylinder front, at the same time, screw back in the reaction material, and through the thrust bearing the thrust seat back, pulling the piston rod through the nut straight back. To complete the measurement, injection, the injection cylinder rod chamber oil inlet through the bearing to push the piston rod to complete the action, the rod chamber piston oil inlet to push the piston rod and screw and finish the injection.The work principle of screw plasticizing components: performs, screw rotation, from the material inlet into the screw groove material advancing continuously forward, heating ring through the barrel wall of the heat transfer to the spiral groove material, solid material in the dual role of external heating and screw rotational shear, and through the thermal process functional section of screw, achieving the plasticizing and melting, melting away the check ring around the screw head, front end through the channel into the screw, and generates backpressure, push the screw after the shift measurement complete melt, at the time of injection screw up, piston effect, with rapid advancement, in the cylinder, will melt reservoir material in the chamber through the nozzle into the mold.Screw plasticizing components generally have the following characteristics:The screw has two functions of plasticizing and injection;The screw in plastic, only for the plasticThe plastics in plasticizing process, thermal process through than extrusion;The screw on the plasticizing and injection were to occur, axial displacement, and screw in working state of intermittent when to stop, thus forming a non - stability of screw plasticizing process.(1) ScrewScrew is a key component of plastic parts, direct contact with plastic, plastic through the effective length of the screw channel, after the heat for a long time, must go through 3 states (glass, behavior, viscous state) transformation, geometric parameters, geometry, length of functional section of screw will directly affect the transmission efficiency and the plasticizing quality of plastic, will ultimately affect the quality of injection molding cycle and product.Compared with the extrusion screw, plastic screw has the following characteristics:The injection screw length-diameter ratio and compression ratio is small;Screw groove of injection screw is section of the deep;The injection screws feeding sections is longer, and are short;The injection screw work, plasticizing capacity and melt temperature will vary with the axial displacement screw and change.(I) classification, screwInjection screw according to the plastic adaptability, can be divided into general and special screw, general also called conventional screw, can be processed with low viscosity, most of the thermoplastic, civil plastic crystalline and amorphous and engineering plastics, is the most basic form of the screw, and the corresponding and special screw, is used to process with ordinary screw processing hard plastic; according to the screw structure and geometry characteristics, can be divided into conventional screw and screw, the conventional screw is also known as the three section screw, is the basic form of the screw, screw form has many kinds, such as separation screw, screw, wavy shunt screw, no metering section of screw.The conventional screw thread effective length is usually divided into feeding sections (conveying), the compression section (Plastics segment), and metering section (averaging period), according to the plastic properties of different, can be divided into gradual, mutation type and general type screw.The tapered screw: compression long, plasticizing energy transfer for PVC relaxation, poor thermal stability of plastic.The mutant compression screw: short, plasticizing energy conversion is more acuteness, used for polyolefin, PA crystalline plastics.The general purpose screw: adaptability is strong, and can be suitable for processing a variety of plastic, avoid frequent replacement of the screw, increase production efficiency.DS screw diameter, screw diameter directly affect the plasticizing capacity, will directly affect the injection volume, therefore, injection volume of injection molding machine the screw diameter is large.L/ds - screw length to diameter ratio. L is the effective length of screw thread part of the screw, the ratio of length to diameter is larger, the length of that thread, directly affect the thermal process of material in the screw, the ability to influence the absorption of energy, while the energy source has two parts: one part is the external heating coil to the barrel, and another part is friction thermal and shear heat generated by the rotation of the screw, the external mechanical energy conversion, therefore, L/ds directly affect the melting effect of material and melt, but if L/ds is too large, the transmission torque increase, increased energy consumption.L1 - feeding length. The feeding section is also called conveying or feed section, in order to improve the transport capacity, screw groove surface must be smooth, the length of the L1 shallensure that the material conveying length too short enough, because L1 will lead to premature melting material, thus it is difficult to guarantee the transportation conditions of stabilizing pressure, will be difficult to ensure the screw later. Plastic under their own gravity from the hopper to slip into the screw, screw rotation, the thrust surface friction in the barrel and screw groove under the action of the material is compressed into a solid, nut intensive, the relative motion along the direction of the thread, this section, plastic solid state, namely the glass state.The depth of screw channel H1 - feed section. H1 deep, is receiving materials, improving the feeding quantity and plasticizing capacity, but will affect the shear strength of material plasticization and screw root, general H1 ≈ (0.12 ~ 0.16) ds.L3 - melting length. Melting section called homogeneous section or the measuring section, melt further homogenization, uniform temperature in the channel of L3 segment, uniform composition, the formation of good quality of melt, the length of L3 is helpful to melt in the screw groove fluctuations, stable pressure, causes the material to feed evenly extruded from the screw head, so it is also called the metering section. L3 short time, help to improve the general screw plasticizing capacity, L3= (4 ~ 5)ds.H3 - melting section of spiral groove depth, H3 small, shallow groove, improves the plasticizing effect of plastic melt, to melt homogenization, but H3 is too small will lead to higher shear rate, and shear heat is too large, causing degradation of the molecular chain, the effect of melt quality,; conversely, if the H3 is too large, the perform, enhanced flow screw back pressure generated, will reduce the plasticizing capacity.L2 - plasticizing period (compression) length of thread. The tapered space material continuously under compression, shear and mixing effect, material from the L2 point, molten pool increased, to the point of weld pool has been occupying the entire screw groove, the material from the glass state through viscoelastic state transition to a viscous state, namely this segment, the plastic is state of coexistence in the particles with a molten body. The length of L2 will affect the transformation of the material from the glassy to viscous flow state, is too short will not change, plugging in the terminal segment of the L2 formation of high pressure, torque or axial force of solid material; too long will increase the screw torque and unnecessary consumption, general L2= (6 ~ 8) ds. For the crystalline plastics, material melting point, melting a narrow range, L2 can be shorter, generally (3 ~ 4) ds, for heat-sensitive plastic, this section Kvetching.S - Pitch, the size effect of helix angle, thus affecting the transport efficiency of screw, general S ≈ ds.E - Compression ratio. ε =h1/h3, namely the feeding section of spiral groove depth H1 and the melting section of spiral groove depth ratio of h3. E, will enhance the shear effect, but will weaken the plasticizing capacity, generally speaking, ε slightly smaller as well, to help improve the plasticizing capacity and increase the adaptability to raw materials, for crystalline plastics, the compression ratio is 2.6~3.0. For low viscosity and thermal stability of plastic, can choose thehigh compression ratio and high viscosity; thermal sensitivity plastic, should choose low compression rate.(2) The screw headIn the injection screw, screw head is: the plastic, can be good plastic melt and releasing to the storage chamber, and in high pressure injection, and can effectively close the melt front screw head, prevent backflow.The screw head is divided into two categories, with check ring and not the inverse ring with the check, the check ring, a plastic screw, melt homogenizing section will check ring away, through the gap formation and the screw head, into the storage chamber, injection pressure, melt screw the head of the formation of thrust, the non-return valve return channel plugging, prevent backflow. For some high viscosity materials such as PMMA, PC, AC or poor thermal stability of PVC material, in order to reduce the retention time of shearing and material, can not check ring, but this injection will produce reflux, prolonging holding time.On the screw head requirements:The screw head to be flexible smooth;The check ring and the cylinder to be suitable with the gap, to prevent melt flow, and flexible; The existing flow section is enough, but also to ensure the check ring face a return force, making fast closed at the time of injection;The structure should be easy disassembly, convenient cleaning;The direction of the screw thread screw and screw in screw head instead, prevent a plastic screw head loose.(3) Cylinder(I), the barrel structureCylinder is an important part of plastic parts; interior screw is arranged outside the heating coil, under complex stress and thermal stress.(II), the feeding portStructure feeding port directly affects feed effect and plastic parts of the feeding ability, injection molding machine most by gravity feed material in hopper, simple manufacture, but feed the negative; the feed material and the screw contact angle, contact area is large, can improve the feed efficiency, is not easy in the hopper into bridge hole.(III), cylinder wall thicknessCylinder wall thickness is of sufficient strength and stiffness, because the barrel to melt and gas pressure, and the barrel length to diameter ratio, cylinder requires enough heat capacity, so the cylinder walls have a certain thickness, otherwise it is difficult to ensure that the temperature stability; but if it is too thick, barrel bulky, waste material, the thermal inertia of large, slow temperature rise, temperature regulation of delay larger.(IV), cylinder clearanceCylinder gap refers to the single gap barrel wall and screw diameter, the gap is too large, plasticizing capacity is reduced, injected back into the discharge increases, injection time, causing material degradation in the process; if it is too small, the thermal expansion effect on the screw and barrel friction, energy consumption increased, even death card, this gap delta = (0.002~0.005) ds.(V), the material heating and cooling tubeInjection molding machine barrel heating with electric resistance, ceramic heating, cast aluminum heating, should be reasonably arranged according to the application and processing of materials, commonly used has the resistance heating and ceramic heating, to comply with the requirements of injection molding process, the barrel to subsection control, small 3, large machine 5.Cooling refers to the feeding mouth is cooling, because the feeding mouth if the temperature is too high, the solid in the feeding mouth "bridge", blocking the outlet, thus affecting the transport efficiency of feed section, so the cooling water jacket is arranged in the cooling it. Our factory is through the cooling circulating water cooling of the feed inlet.(4) Nozzle(I) function of spray nozzleThe nozzle is an important part of connecting plasticizing device and mold flow; nozzle has a variety of functions:The perform, establishment of backpressure, degassed, prevent melt salivation, improve plasticizing capability and measurement precision;The injection mold, forming the contact pressure and the main cast, keep good contact with pouring nozzle sleeve, forming a closed channel, to prevent the plastic melt under high pressure overflow;injection, establish the melt pressure, shear stress, and the pressure head into the velocity head, the increase of shear rate and temperature, enhance mixing and homogenizing;Changing the nozzle structure to match the mold and plasticizing device, a new type of flow channel or injection system;The nozzle also bears the thermostat, thermal insulation and cutting function;The reducing melts in the import and export of the viscoelastic effect and the eddy loss, in order to stabilize its flow;The holding pressure, easy to mold products of feeding, and the cooling shaping increased reflow resistance, reduce or prevent the melt in the cavity to return.(II) The basic form, nozzleNozzle can be divided into straight-through nozzle, locking type nozzle, hot runner nozzle and the flow nozzle, the present stage our factory are straight-through nozzle.Straight-through nozzle is the nozzle is widely applied, its characteristic is the direct and main casting mold nozzle spherical contact, the nozzle radius and the channel than the mold to be small, injection pressure, melt directly through the mold runner system is filled into the cavity, fast speed, low pressure loss, manufacturing and installation are all relatively convenient.Locking type nozzle is mainly to solve the problem through the nozzle salivation, suitable for low viscosity polymer (such as PA) processing. In the closing the nozzle plastic, prevent melt salivation phenomenon, and when the injection and injection pressure to open, so that melt into the mold cavity.2 injection cylinderIts working principle is: the injection cylinder into the oil, the piston drives the piston rod and the bearing is arranged on the thrust seat, drive screwPush the screw forward or backward. Through the nut piston rod head, can adjust the timing of two parallel to the axial position of the piston rod and the injection screw axial position.3 thrust bearingInjection, thrust bearing thrust shaft driven by screw injection; while the plastic, the oil motor drive screw rotation to achieve thrust shaft drives the perform.4 cylindersWhen a moving oil cylinder into the oil, forward seat injection or the back action, and to ensure the injection nozzle and mould the main cast set of circular arc closely contact, the injection pressure can seal the melt.The 5 part accuracy requirements for injectionAfter the assembly, the components are arranged on the machine frame, must ensure that the nozzle and mold water sleeve is tightly bonding, in order to prevent overflow, the center line of injection parts requirements and the clamping parts of the center line of concentric; in order to ensure the accuracy of injection screw and barrel inner hole, must ensure that the two injection cylinder bore and the center cylinder hole is parallel with the center line of symmetry; in the horizontal plane, parallelism and symmetry for the center of a moving oil cylinder two guide holes also must ensure that the vertical machine, it must ensure that the two seat moving oil cylinder hole and a cylinder positioning the center hole is parallel with the center line of symmetry. Factors affecting the location accuracy of hole and shaft are associated parts size precision, geometric accuracy, precision and assembly precision.Each kind of plastic, has an ideal plastic processing temperature range, should control the processing temperature of barrel, which is close to the temperature range. Granular plastic from the hopper into the barrel, the first will arrive at a feeding section, in the feeding section will appear dry friction, when the plastic is heated, melting is not uniform, very easy to cause the barrel wall and screw wear surface. Similarly, the compression section and the entire segment, if the molten state disorder plastic uneven will result in increased wear.Speed should be adjusted properly. The friction force of these substances on the metal material is often much larger than the molten plastic. In the plastic injection molding, if using high speed in the shear stress on the plastic at the same time, it will also strengthen correspondingly more torn fibers, the torn fibers containing sharp end, to wear a large force to increase. Inorganic minerals on the surface of metal high-speed taxiing, the scraping is not a small role. So the speed should not be too high.In addition to check in plastic debris, the original purchase fresh plastic and no debris, but after weighing, transport, drying, mixing, especially to add recycling back material, there may be mixed with debris. Small as metal filings, as big as a heating ring nut clip, or clusters of warehouse key, mixed into the barrel had occurred, the screw damage is self-evident. (barrel of course also damage), therefore must install the magnetic iron material, strict management and monitoring. Moisture in plastics has a certain effect on the wear surface of the screw. If the plastic in injection unprecedented will eliminate all residual moisture, moisture into the screw compression section, they formed before melt blend in molten plastic with high temperature and high pressure "steam particles", with the injection process screw propulsion, from homogeneous section until the screw head, these "steam" particle, pressure drop and expansion in the injection process, the impurities such as a fine grain, rubbing on the wall damage. In addition, for some types of plastic, under high temperature and high pressure, the water may become a catalyst for cracking of plastic, harmful impurities can corrode the metal surface. Therefore, the drying work plastic injection before, not only has a direct relationship to the product quality, but also affects the service life of the screw.中文译文注塑成型机注塑成型机简称注塑机。

外文文献翻译(含：英文原文及中文译文)英文原文Hydraulic systemW Arnold1 IntroductionThe hydraulic station is called a hydraulic pump station and is an independent hydraulic device. It is step by step to supply oil. And control the direction of hydraulic oil flow, pressure and flow, suitable for the host and hydraulic equipment can be separated on the various hydraulic machinery.After the purchase, the user only needs to connect the hydraulic station and the actuator (hydraulic or oil motor) on the mainframe with different tubings. The hydraulic machine can realize various specified actions and working cycles.The hydraulic station is a combination of manifolds, pump units or valve assemblies, electrical boxes, and tank electrical boxes. Each part function is:The pump unit is equipped with a motor and an oil pump, which is the power source of the hydraulic station and can convert mechanical energy into hydraulic oil pressure energy.V alve combination - its plate valve is mounted on the vertical plate, and the rear plate is connected with the same function as the manifold.Oil manifolds - assembled from hydraulic valves and channel bodies. It regulates hydraulic oil pressure, direction and flow.Box--a semi-closed container for plate welding. It is also equipped with an oil screen, an air filter, etc., which is used for cooling and filtering of oil and oil.Electrical box - divided into two types: one is to set the external lead terminal board; one is equipped with a full set of control appliances.The working principle of the hydraulic station: The motor drives the oil pump to rotate, then the pump sucks oil from the oil tank and supplies oil, converts the mechanical energy into hydraulic pressure energy, and the hydraulic oil passes through the manifold (or valve assembly) to adjust the direction, pressure and flow and then passes through the external tube. The way to the hydraulic cylinder or oil motor in the hydraulic machinery, so as to control the direction of the hydraulic motor, the strength of the speed and speed, to promote all kinds of hydraulic machinery to do work.(1) Development history of hydraulic pressureThe development history of hydraulics (including hydraulic power, the same below), pneumatics, and seals industry in China can be roughly divided into three stages, namely: the starting stage in the early 1950s to the early 60s; and the professional in the 60s and 70s. The growth stage of the production system; the 80-90's is a stage of rapid development. Among them, the hydraulic industry began in the early 1950s with thedevelopment of hydraulic machines such as Grinding Machines, broaching machines, and profiling lathes, which were produced by the machine tool industry. The hydraulic components were produced by the hydraulic workshop in the machine tool factory, and were produced for self use. After entering the 1960s, the application of hydraulic technology was gradually promoted from the machine tool to the agricultural machinery and engineering machinery. The original hydraulic workshop attached to the main engine plant was independent and became a professional manufacturer of hydraulic components. In the late 1960s and early 1970s, with the continuous development of mechanization of production, particularly in the provision of highly efficient and automated equipment for the second automobile manufacturing plant, the hydraulic component manufacturing industry witnessed rapid development. The batch of small and medium-sized enterprises also began to become specialized manufacturers of hydraulic parts. In 1968, the annual output of hydraulic components in China was close to 200,000 pieces. In 1973, in the fields of machine tools, agricultural machinery, construction machinery and other industries, the professional factory for the production of hydraulic parts has grown to over 100, and its annual output exceeds 1 million pieces. Such an independent hydraulic component manufacturing industry has taken shape. At this time, the hydraulic product has evolved from the original imitation Su product intoa combination of imported technology and self-designed products. The pressure has been developed towards medium and high pressures, and electro-hydraulic servo valves and systems have been developed. The application of hydraulics has been further expanded. The pneumatic industry started a few years later than hydraulics, and it was only in 1967 that it began to establish a professional pneumatic components factory. Pneumatic components began to be manufactured and sold as commodities. Its sealing industry including rubber seals, flexible graphite seals, and mechanical seals started from the production of common O-rings, oil seals, and other extruded rubber seals and asbestos seal products in the early 1950s. In the early 1960s, it began to develop and produce flexible products. Graphite seals and mechanical seals and other products. In the 1970s, a batch of batches of professional production plants began to be established one after another in the systems of the former Ministry of Combustion, the Ministry of Agriculture, and the Ministry of Agricultural Machinery, formally forming the industry, which laid the foundation for the development of the seal industry.In the 1980s, under the guidance of the national policy of reform and opening up, with the continuous development of the machinery industry, the contradiction between the basic components lags behind the host computer has become increasingly prominent and caused the attention of all relevant departments. To this end, the former Ministry of Machinesestablished the General Infrastructure Industry Bureau in 1982, and unified the original pneumatic, hydraulic, and seal specialties that were scattered in the industries of machine tools, agricultural machinery, and construction machinery, etc. The management of a piece of office, so that the industry in the planning, investment, the introduction of technology and scientific research and development and other aspects of the basic parts of the bureau's guidance and support. This has entered a period of rapid development, it has introduced more than 60 foreign advanced technology, of which more than 40 hydraulic, pneumatic 7, after digestion and absorption and technological transformation, are now mass production, and has become the industry's leading products . In recent years, the industry has intensified its technological transformation. From 1991 to 1998, the total investment of national, local, and corporate self-raised funds totaled about 2 billion yuan, of which more than 1.6 billion were hydraulic. After continuous technological transformation and technological breakthroughs, the technical level of a group of major enterprises has been further improved, and technological equipment has also been greatly improved, laying a good foundation for forming a high starting point, specialization, and mass production. In recent years, under the guidance of the principle of common development of multiple ownership systems in the country, various small and medium-sized enterprises with different ownership have rapidly emerged and haveshown great vitality. With the further opening up of the country, foreign-funded enterprises have developed rapidly, which plays an important role in raising industry standards and expanding exports. So far China has established joint ventures with famous manufacturers in the United States, Germany, Japan and other countries or directly established piston pumps/motors, planetary speed reducers, hydraulic control valves, steering gears, hydraulic systems, hydrostatic transmissions, and hydraulic components. The company has more than 50 manufacturing enterprises such as castings, pneumatic control valves, cylinders, gas processing triplets, rubber seals, and mechanical seals, and has attracted more than 200 million U.S. dollars in foreign capital.(2) Current statusBasic profileAfter more than 40 years of hard work, China's hydraulics, pneumatics and seals industry has formed a complete industrial system with a certain level of production capacity and technical level. According to the statistics of the third n ational industrial census in 1995, China’s state-owned, privately-owned, cooperative, village-run, individual, and “funded enterprises” have annual sales income of more than 1 million yuan in hydraulic, pneumatic, and seal industrial townships and above. There are a total of more than 1,300 companies, including about 700 hydraulics, and about 300 pneumatic and sealing parts. According to thestatistics of the international industry in 1996, the total output value of the hydraulic industry in China was about 2.448 billion yuan, accounting for the 6th in the world; the total output value of the pneumatic industry was about 419 million yuan, accounting for the world’s10 people.2. Current supply and demand profileWith the introduction of technology, independent development and technological transformation, the technical level of the first batch of high-pressure plunger pumps, vane pumps, gear pumps, general hydraulic valves, oil cylinders, oil-free pneumatic components and various types of seals has become remarkable. Improve, and can be stable mass production, provide guarantees for all types of host to improve product quality. In addition, certain achievements have also been made in the aspects of CAD, pollution control, and proportional servo technology for hydraulic pneumatic components and systems, and have been used for production. So far, the hydraulic, pneumatic and seal products have a total of about 3,000 varieties and more than 23,000 specifications. Among them, there are about 1,200 types of hydraulic pressure, more than 10,000 specifications (including 60 types of hydrodynamic products, 500 specifications); about 1350 types of pneumatic, more than 8,000 specifications; there are also 350 types of rubber seals, more than 5000 The specifications are now basically able to adapt to the general needs ofvarious types of mainframe products. The matching rate for major equipment sets can reach more than 60%, and a small amount of exports has started.In 1998, the domestic production of hydraulic components was 4.8 million pieces, with sales of about 2.8 billion yuan (of which mechanical systems accounted for 70%); output of pneumatic components was 3.6 million pieces, and sales were about 550 million yuan (including mechanical systems accounting for about 60%) The production of seals is about 800 million pieces, and the sales volume is about 1 billion yuan (including about 50% of mechanical systems). According to the statistics of the annual report of the China Hydraulic and Pneumatic Sealing Industry Association in 1998, the production and sales rate of hydraulic products was 97.5% (101% of hydraulic power), 95.9% of air pressure, and 98.7% of seal. This fully reflects the basic convergence of production and sales.Although China's hydraulic, pneumatic and sealing industries have made great progress, there are still many gaps compared with the development needs of the mainframe and the world's advanced level, which are mainly reflected in the variety, performance and reliability of products. . Take hydraulic products as an example, the product varieties are only 1/3 of the foreign country, and the life expectancy is 1/2 of that of foreign countries. In order to meet the needs of key hosts, imported hosts, and majortechnical equipment, China has a large number of imported hydraulic, pneumatic, and sealing products every year. According to customs statistics and relevant data analysis, in 1998, the import volume of hydraulic, pneumatic and seal products was about 200 million U.S. dollars, of which the hydraulic pressure was about 140 million U.S. dollars, the pneumatics were 30 million U.S. dollars, and the seal was about 0.3 billion U.S. dollars. The year is slightly lower. In terms of amount, the current domestic market share of imported products is about 30%. In 1998, the total demand for hydraulic parts in the domestic market was about 6 million pieces, and the total sales volume was 4 billion yuan; the total demand for pneumatic parts was about 5 million pieces, and the total sales volume was over 700 million yuan; the total demand for seals was about 1.1 billion yuan. Pieces, total sales of about 1.3 billion yuan. (3) Future developments1. The main factors affecting development(1) The company's product development capability is not strong, and the level and speed of technology development can not fully meet the current needs for advanced mainframe products, major technical equipment and imported equipment and maintenance;(2) Many companies have lagged behind in manufacturing process, equipment level and management level, and their sense of quality is not strong, resulting in low level of product performance, unstable quality,poor reliability, and insufficiency of service, and lack of user satisfaction. And trusted branded products;(3) The degree of professional specialization in the industry is low, the power is scattered, the duplication of the low level is serious, the product convergence between the region and the enterprise leads to blind competition, and the prices are reduced each other, thus the efficiency of the enterprise is reduced, the funds are lacking, and the turnover is difficult. Insufficient investment in development and technological transformation has severely restricted the overall level of the industry and its competitive strength.(4) When the degree of internationalization of the domestic market is increasing, foreign companies have gradually entered the Chinese market to participate in competition, coupled with the rise of domestic private, cooperative, foreign-funded, and individual enterprises, resulting in increasing impact on state-owned enterprises. .2. Development trendWith the continuous deepening of the socialist market economy, the relationship between supply and demand in the hydraulic, pneumatic and sealed products has undergone major changes. The seller market characterized by “shortage” has basically become a buyer’s market characterized by “structured surplus”. Replaced by. From the perspective of overall capacity, it is already in a trend of oversupply, and in particular,general low-grade hydraulic, pneumatic and seals are generally oversupply; and like high-tech products with high technological content and high value and high value-added products that are urgently needed by the host, Can not meet the needs of the market, can only rely on imports. After China's entry into the WTO, its impact may be greater. Therefore, during the “10th Five-Y ear Plan” period, the growth of the industry’s output value must not only rely on the growth of quantity. Instead, it should focus on the structural contradiction of the industry and intensify efforts to adjust the industrial structure and product structure. It should be based on the improvement of quality. Product technology upgrades in order to adapt to and stimulate market demand, and seek greater development.2. Hydraulic application on power slide(1) Introduction of Power Sliding TableUsing the binding force curve diagram and the state space analysis method to analyze and study the sliding effect and the smoothness of the sliding table of the combined machine tool, the dynamics of the hydraulic drive system of the sliding table—the self-regulating back pressure regulating system are established. mathematical model. Through the digital simulation system of the computer, the causes and main influencing factors of the slide impact and the motion instability are analyzed. What kind of conclusions can be drawn from those, if we canreasonably design the structural dimensions of hydraulic cylinders and self-regulating back pressure regulators ——The symbols used in the text are as follows:s 1 - flow source, that is, the flow rate of the governor valve outlet;S el —— sliding friction of the sliding table;R - the equivalent viscous friction coefficient of the slide;I 1 - quality of slides and cylinders;12 - self-adjusting back pressure valve core quality;C 1, c 2 - liquid volume without cylinder chamber and rod chamber;C 2 - Self-adjusting back pressure valve spring compliance;R 1, R2 - Self-adjusting back pressure valve damping orifice fluid resistance;R 9 - Self-adjusting back pressure valve valve fluid resistance;S e2——initial pre-tightening force of self-adjusting back pressure valve spring;I 4, I5 - Equivalent liquid sense of the pipeline;C 5, C 6 - equivalent liquid capacity of the pipeline;R 5, R7 - Equivalent liquid resistance of the pipeline;V 3, V4 - cylinder rodless cavity and rod cavity volume;P 3, P4—pressure of the rodless cavity and rod cavity of the cylinder;F - the slide bears the load;V - speed of slide motion;In this paper, the power bond diagram and the state space splitting method are used to establish the system's motion mathematical model, and the dynamic characteristics of the slide table can be significantly improved.In the normal operation of the combined machine tool, the magnitude of the speed of the slide, its direction and the load changes it undergoes will affect its performance in varying degrees. Especially in the process of work-in-process, the unsteady movement caused by the advancing of the load on the slide table and the cyclical change of the load will affect the surface quality of the workpiece to be machined. In severe cases, the tool will break. According to the requirements of the Dalian Machine Tool Plant, the author used the binding force curve diagram and the state space analysis method to establish a dynamic mathematical model of a self-adjusting back pressure and speed adjustment system for the new hydraulic drive system of the combined machine tool slide. In order to improve the dynamic characteristics of the sliding table, it is necessary to analyze the causes and main influencing factors of the impetus and movement of the sliding table. However, it must pass the computer's digital simulation and the final results obtained from the research.(2) Dynamic Mathematical ModelThe working principle diagram of the self-adjusting back pressure speedregulation system of the combined machine tool slide hydraulic drive system is shown in the figure. This system is used to complete the work-cycle-stop-rewind. When the sliding table is working, the three-position four-way reversing valve is in the illustrated position. The oil supply pressure of the oil pump will remain approximately constant under the effective action of the overflow valve, and the oil flow passes through the reversing valve and adjusts the speed. The valve enters the rodless chamber of the cylinder to push the slide forward. At the same time, the pressurized oil discharged from the rod chamber of the cylinder will flow back to the tank through the self-regulating back pressure valve and the reversing valve. During this process, there was no change in the operating status of both the one-way valve and the relief valve. The complex and nonlinear system of the hydraulic drive system of the self-adjusting back pressure governor system is a kind of self-adjusting back-pressure governor system. To facilitate the study of its dynamic characteristics, a simple and reasonable dynamic mathematical model that only considers the main influencing factors is established. Especially important [1][2]. From the theoretical analysis and the experimental study, we can see that the system process time is much longer than the process time of the speed control valve. When the effective pressure bearing area of the rodless cavity of the fuel tank is large, the flow rate at the outlet of the speed control valve is instantaneous. The overshoot is reflected in thesmall change in speed of the slide motion [2]. In order to further broaden and deeply study the dynamic characteristics of the system so that the research work can be effectively performed on a miniature computer, this article will further simplify the original model [2], assuming that the speed control valve is output during the entire system pass. When the flow is constant, this is considered to be the source of the flow. The schematic diagram of the dynamic model structure of this system is shown in Fig. 2. It consists of a cylinder, a sliding table, a self-adjusting back pressure valve, and a connecting pipe.The power bond graph is a power flow graph. It is based on the transmission mode of the system energy, based on the actual structure, and uses the centralized parameters to represent the role of the subsystems abstractly as a resistive element R, a perceptual element I, and a capacitive element. Three kinds of role of C. Using this method, the physical concept of modeling is clear, and combined with the state-space analysis method, the linear system can be described and analyzed more accurately. This method is an effective method to study the dynamic characteristics of complex nonlinear systems in the time domain. According to the main characteristics of each component of the self-adjusting back pressure control system and the modeling rules [1], the power bond diagram of the system is obtained. The upper half of each key in the figure represents the power flow. The two variables that makeup the power are the force variables (oil pressure P and force F) and the flow variables (flow q and velocity v). The O node indicates that the system is connected in parallel, and the force variables on each key are equal and the sum of the flow variables is zero; 1 The nodes represent the series connection in the system, the flow variables on each key are equal and the sum of the force variables is Zero. TF denotes a transformer between different energy forms. The TF subscripted letter represents the conversion ratio of the flow variable or the force variable. The short bar on the key indicates the causal relationship between the two variables on the key. The full arrow indicates the control relationship. There are integral or differential relationships between the force and flow variables of the capacitive and perceptual elements in the three types of action elements. Therefore, a complex nonlinear equation of state with nine state variables can be derived from Fig. 3 . In this paper, the research on the dynamic characteristics of the sliding table starts from the two aspects of the slide's hedging and the smoothness of the motion. The fourth-order fixed-length Runge-Kutta is used for digital simulation on the IBM-PC microcomputer.(3) Slide advanceThe swaying phenomenon of the slide table is caused by the sudden disappearance of the load acting on the slide table (such as drilling work conditions). In this process, the table load F, the moving speed V, and thepressure in the two chambers of the cylinder P3 and P4 can be seen from the simulation results in Fig. 4. When the sliding table moves at a uniform speed under the load, the oil pressure in the rodless cavity of the oil cylinder is high, and a large amount of energy is accumulated in the oil. When the load suddenly disappears, the oil pressure of the cavity is rapidly reduced, and the oil is rapidly reduced. When the high-pressure state is transferred to the low-pressure state, a lot of energy is released to the system, resulting in a high-speed forward impact of the slide. However, the front slide of the sliding table causes the pressure in the rod cavity of the oil cylinder to cause the back pressure to rise, thereby consuming part of the energy in the system, which has a certain effect on the kicking of the slide table. We should see that in the studied system, the inlet pressure of the self-adjusting back pressure valve is subject to the comprehensive effect of the two-chamber oil pressure of the oil cylinder. When the load suddenly disappears, the pressure of the self-adjusting back pressure valve rapidly rises and stably exceeds the initial back pressure value. It can be seen from the figure that self-adjusting back pressure in the speed control system when the load disappears, the back pressure of the cylinder rises more than the traditional speed control system, so the oil in the rod cavity of the cylinder absorbs more energy, resulting in the amount of forward momentum of the slide It will be about 20% smaller than traditionalspeed control systems. It can be seen from this that the use of self-adjusting back-gear speed control system as a drive system slider has good characteristics in suppressing the forward punch, in which the self-adjusting back pressure valve plays a very large role.(4) The smoothness of the slideWhen the load acting on the slide changes periodically (such as in the case of milling), the speed of the slide will have to fluctuate. In order to ensure the processing quality requirements, it must reduce its speed fluctuation range as much as possible. From the perspective of the convenience of the discussion of the problem, assume that the load changes according to a sine wave law, and the resulting digital simulation results are shown in Figure 5. From this we can see that this system has the same variation rules and very close numerical values as the conventional speed control system. The reason is that when the change of the load is not large, the pressure in the two chambers of the fuel tank will not have a large change, which will eventually lead to the self-regulating back pressure valve not showing its effect clearly.(5) Improvement measuresThe results of the research show that the dynamic performance of a sliding table with self-regulating back pressure control system as a drive system is better than that of a traditional speed control system. To reduce the amount of kick in the slide, it is necessary to rapidly increase the backpressure of the rod cavity when the load disappears. To increase the smoothness of the sliding table, it is necessary to increase the rigidity of the system. The main measure is to reduce the volume of oil. From the system structure, it is known that the cylinder has a large volume between the rod cavity and the oil discharge pipe, as shown in Fig. 6a. Its existence in terms of delay and attenuation of the self-regulating back pressure valve function, on the other hand, also reduces the rigidity of the system, it will limit the further improvement of the propulsion characteristics and the smoothness of the motion. Thus, improving the dynamic characteristics of the sliding table can be handled by two methods: changing the cylinder volume or changing the size of the self-regulating back pressure valve. Through the simulation calculation of the structural parameters of the system and the comparison of the results, it can be concluded that the ratio of the volume V4 between the rod cavity and the oil discharge pipe to the volume V3 between the rodless cavity and the oil inlet pipe is changed from 5.5 to 5.5. At 1 oclock, as shown in the figure, the diameter of the bottom end of the self-adjusting back pressure valve is increased from the original 10mm to 13mm, and the length of the damper triangle groove is reduced from the original lmm to 0.7mm, which will enable the front of the slide table. The impulse is reduced by 30%, the transition time is obviously shortened, and the smoothness of the slide motion will also be greatly improved.中文译文液压系统W Arnold1. 绪论液压站称液压泵站,是独立的液压装置。

中文6236字出处：Journal of Materials Processing Technology, 2005, 164: 1294-1300注射成型模具温度调节系统的设计和优化D.E. Dimla a, ∗, M. Camilotto b, F. Miani b伯恩茅斯工程和计算设计大学，英国，多塞特，伯恩茅斯，基督城摘要随着消费寿命越来越短，诸如手机的电子产品在人群中变的越来越时尚，注塑成型依然是成型此类相关塑料零件产品的最热门方法。

成型过程中熔融聚合物被注入模具型腔内，经过冷却，最后脱模塑料零件产品。

在一个完整的注塑成型的过程主要有三个阶段，冲模，冷却和脱模。

成型周期决定生产的成本效益。

相应地，其中三个阶段中，冷却阶段是最重要的一步，它决定零件的生产速率。

这项研究的主要目的在于使用的有限元分析和传热分析在注塑成型工具中配置一个最优的和最有效的冷却/加热的水道。

一个适合注塑成型典型的组件3D CAD 模型的最佳的形状的设计完成之后，用来成型塑料零件的型芯和型腔的设计才得以实现。

这些也用在有限元分析和热分析，首先确定注射入口的最佳位置，然后确定冷却渠道。

这两个因素对成型周期影响最大，如果要减少的成型周期时间，那么，首先必须对这些因素进行优化并使其减至最低。

分析虚拟模型表明，与传统冷却模具相比，这样设计的冷却水道将大大减少循环时间，以及明显的改善制品质量和表面光洁度。

关键字模具设计优化，注塑成型1 引言：注射成型是塑料部件工业生产中其一个利用最多的生产过程。

它的成功在于，与其它成型方式相比，如吹塑成型，有高的三维形状塑造造能力，能带来更高的效益。

注塑成型的基本原则是一种固体聚合物经加热熔融后注入一模具型腔;然后经冷却后从模具脱模，获得与型腔结构相似的制品。

因此一个注塑成型的过程的主要阶段，涉及充模，冷却和制品脱模。

成型过程的成本效益，由成型所花的时间即成型周期决定。

相应地，其中三个阶段中，冷却阶段是最重要的一步，它决定零件的生产速率。

(文档含英文原文和中文翻译)中英文资料对照外文翻译The hydraulic system constitutionhydraulic system composition department wind and the function, widely is applying on each kind of mechanical device the hydraulic system, the use has the continual fluid fat liquor now, actuates through the hydraulic pump the hydraulic pump the electric motor or the engine mechanical energy transforms the fat liquor the pressure energy, passes through each kind of control valve, delivers took the actuator in the hydraulic cylinder motor, transforms again while the mechanical power actuates the load. Constitutes such hydraulic system each constituent and the function. The hydraulic system characteristic and the use hydraulic pressure took one transmission technology, has its prominent merit:Can produce the very big power, moreover controls easily; May use the pump to obtain very the high pressure (20-30MPa) hydraulic fluid very easily, sends in this pressure oil the hydraulic cylinder then to produce the very big strength; Can in the very wide scope the limitless speed change; To altogether gives the oil motor or the hydraulic cylinder current capacity with the control valve carries on the stepless adjustment, then at will controls its revolving or the translation speed; Very easy to prevent the overload, the security is big; The size slightly strives in a big way, installs the position to be possible the free choice; Output strength adjustment simple accurate, but long-distance control.Hydraulic system use and service, in order to guarantee the mechanical device non-breakdown the work, must follow the factory the use service request.The hydraulic system is infinitely varied, took the different machinery a constituent, its use matters needing attentionalso differ from naturally.The hydraulic system uses and services the duty including the debugging, the inspection, the service and the repair. How debugs? The debugging is causes the new equipment to put the operation or to cause the original equipment to put the operation a series of activities, including the installment, the oil injection, the flushing, the adjustment, runs gathers. The inspection is examined system active status and function is whether correct, including the observation, the survey and tries to move.The maintenance is refers to the guarantee system the normal function, the few attrition and the replacement wearing parts, including the cleaning up and the replacement components, namely trades the oil, trades ponders the core, trades the seal.The repair is system reply function a series of activities which causes to crash.First must according to the breakdown phenomenon determine expires the spot and verifies the expiration reason, this is the so-called breakdown diagnosis. Then the replacement expiration part, makes the mechanical device to restore the work, this named repair.The expiration part should return the plant to repair.Time use service matters needing attention: When security, use and service hydraulic system, when most important question pays attention to the security, for guarantees the security, has the pressure when the system does not have to loosen the pipe connection, the screw joint or the part.Certainly must put first down the load, causes the pump engine off and releases the accumulator the pressure oil, then opens the thing again, does not have the oil used to work. Although many practical security taboo into general knowledge, but the attention often concentrates in the breakdown phenomenon, but neglects the latent danger.Therefore, in starts to repair the system reason this implementation standardization the engine off procedure, after the repair draws up invests the movement, should implement standardized the again start procedure:Engine off procedure it including following several aspects:1. Puts the low suspension the load or carries on the machinery supports and protections to it.2. Release system3. In release accumulator pressure oil4. Release pressure intensifier both sides pressure oil5. Cut-off electricity control system6.DumpStarts the procedure including following several aspects:1. Elimination expiration root2. If the component failure or the replacement period pollutant enters the system, then according to needs to clean up or the flushing system3. Confirms the part correctly unmistakable4. Confirms the hydraulic pressure connection correctly unmistakable5. Confirms the electrical connection correctly unmistakable6. Adjustable part to secure state7. Fills the oil for the pump and the motor shell8. According to needs to refuel to the system and to deflate9. Relieves the secure interconnection to protect10. Calls the alarm bell and the notice all presents the personnel soon to restart11.Starting systemThe item which this is carries on when service must pay attention, in regarding its sanitary, when service also must pay attention, when service hydraulic system, must do utmost the attention absolutely clean Arab League condition, because the pollutant is the hydraulic system most dangerous enemy.Does not have to carry on the polish and the welding work in the service hydraulic system scene. Loosens in front of the thread must its outside clean first cleanly.With clean returns to protects changes passes over the system the interior to use to open the mouth to seal, guards against the pollutant to enter thesystem.Cleans up when the fuel tank does not permit the use cotton and kapok silk and the rags.Must pass through the filter to the system oil injection.In the tubing, refuels with the flushing is the maintenance clean important link, its matters needing attention are as follows:1. The tubing pipe or the hose damage when must replace immediately.When chooses the pipe, the hose, the screw connector or the flange, must guarantee the pressure rated value (i.e. wall thickness, material quality and so on) satisfy the operation requirements.The hard tube must use the seamless steel pipe.The steel pipe and the metal pipe connection must clean absolutely before the installment, does not have the oil dirt, to scale, the welding, the scrap and so on.May use the steel wire brush, the tube cleaner to clean up or the acid pickling.In front of the acid pickling pipe must carry on degreasing processing, after the acid pickling must clean thoroughly. After cutting in the pipe bank or ridge between fields should the articulation awl hole, remove the burr which possibly has, but cannot ream excessively in order to avoid sells the weak connection.After assembly the pipe does not have again to weld or the gas welding, because is unable to clean up.The hose should the curved several times in order to release any detention the dirty thing.In front of the elbow piece the tubing wants the annealing, prevented when elbow piece the corrugation or changes flat.Wants the accurate elbow piece, enable the pipe then not to arrive after the elastic deformation. The flange must in the fitting surface coordinate smoothly before, and with the length suitable bolt fastening, whether there is the screw connector does install should inspect in the thread the metal burr, in the straight thread does not permit the use seal bandage.If the drive pipe must deposit period of time, should stop up the orifice to prevent the foreign matter enters.But does not have to use the rags or other moves the capital to stop up the orifice, because this only can bring the contamination concern, should use the size appropriate seal cap.2. Refuels the oil drum to want horizontal-type depositing, as far as possible deposits in the room or the awning, opens in front of the oil tung, cleans the barrel to go against and the bung thoroughly, prevented the soil and other outside pollutant enter the fat liquor.Only with the clean vessel, the hose and so on transports the fat liquor from the oil drum to the fuel tank.The recommendation with has at least in the 25um filter feeding pump. Provides 200 goals in the fuel tank oiling tube to ponder the net.The filter is actually specially for the system need oil fluid variety use.Sometimes also discovers the pollutant in the new fat liquor, therefore should for work through the portable purifier the hydraulic system tops up. When portable purifier hose involvement fuel tank, should use cloth attachment cleaning which clean does not shed hair to be clean, prevented the soil and other impurities enter the system.3.Before flushing flushing should take down the precise system part, but installs the pipe nipple in its position or hollow.From the main pipeline which flushes is dismantled the system to ponder the core.The flushing current capacity should for the system anticipated current capacity 2-2.5 times.If possible, use heat flush fluid (85℃).Each time only flushes a leg, from most approaches the wash out pump the return route start, to the downstream advancement, this possibly must additionally build in turn in the system up to the valve, realizes this kind of plan. Cannot use the system pump to take the wash out pump.Generally speaking, the power type pump like centrifugal pump and so on may provide the enough flood peak and the great current capacity, the movement quite is economical, and to flushes the period circulation the pollutant to have the good es the capacity in the flushing system with to use the flushing filter which the current capacity matches, the filtration precision to be as far as possible high, does not have to be lower than the recommendation system filtration precision. If has the possibility, uses the assistance to flush the fuel tank to avoid the pollutant being detained in the system fuel tank.The establishment fat liquor sample plan inspects dustiness, thus determined when finished the flushing procedure.After flushing, takes all measures to prevent when rewiring work part leads the pollutant.4.The replacement part part model must correct unmistakable.When if cannot find the similar model the part to have to use the similar part substitutes, must pay attention to the function, the parameter, the connection size is whether consistent, but also must pay attention installs the position, the ambient temperature, the working voltage and so on.The old seal packing collar must replace, does not permit two uses.The bolt and the screw connector must even screw tight the big stipulation the torque, prevents the part distortion influence work. The adjustable part like delivery valve, the flow valve, the variable displacement pump and so on must establish.5.When accumulator accumulator pressure vessel, Asia locality related safety rule compulsory control.In is loaded with on the accumulator hydraulic system carries on in front of any work, must first download the system pressure.The accumulator shell does not permit the welding and the processing, does not repair when possibly causes the serious accident, therefore must have to repair the accumulator returns delivers the plant to carry on the repair.Hydraulic pump selection: The hydraulic pump is the hydraulic system power supply.Must select can adapt the pressure which the actuator requests to have the return route pump, simultaneously must consider fully the reliability, the life Maintainability one side and so on elect the pump can plant the long-term movement in the system.The hydraulic pump type are extremely many, its characteristic also has the very big difference. Chooses when the hydraulic pump must consider the factor has working pressure, current capacity, rotational speed, quota or variable, variable way, volumetric efficiency, overall effectiveness index, the prime mover type, the noise, the pressure oscillation rate, self-absorption ability and so on, but also must consider and the hydraulic fluid compatibility, the size, the weight, the economy, Maintainability, these factors.The hydraulic pump discharge pressure should be the actuator needs the pressure, the tubing pressure loses, the control valve sum of pressure loss, it does not have to surpass in the sample the rated pressure, when the emphasis security, the reliability.Also should leave leeway the big leeway.In when sample highest working pressure when short-term impact permits pressure.If each circulation plants all has the impact pressure, the pump life can reduce obviously, even the pump can damage.Hydraulic pump life: The hydraulic pump is the hydraulic system power part, its function is transforms the prime mover mechanical energy the liquid the pressure energy, refers to in the hydraulic system the oil pump, it provides the power to the entire hydraulic system.Hydraulic pump structural style common toothed wheel pump, vane pump and ram pump. Affects the hydraulic pump the service life factor to be very many, except outside pump own design, manufacture factor and some with pump use Guanyuan (for example shaft coupling, oil filter and so on) selects, in the test run movement process operation and so on also concerns.1.The air compressorselects the air compressor the basis is the working pressure and the current capacity which the pneumatic system needs.At present, the pneumatic system commonly used working pressure is 0.5~0.8MPa, may select the rated pressure is directly the 0.7~1MPa low-pressure air compressor, the special need fluid may select, high-pressured or the ultrahigh voltage air compressor. When determination air compressor air displacement, should satisfy the biggest gas consumption which each air operated equipment needs (to be supposed to transform into free air gas consumption) the sum.(1) was mad the source refining equipmentgeneral use the air compressor all uses the oil lubrication, the air is compressed in the air compressor, the temperature may elevate 140~170℃, by now were partial the lubricating oil to turn the gas, mixed in the compressed air, in addition in the air water and the dust, formed included mix impurity and so on the water vapor, oil gas, dust compressed air.Ifprovides this kind of compressed air to the air operated equipment use, will be able to have following adverse consequences:Gathers in the compressed air the oil gas to gather in the gas storage fills forms the combustible, even has the detonation danger; Simultaneously the oil vaporizes after the high temperature forms the organic acid, causes the hardware to corrode, affects the equipment the life.(2)The mix impurity deposition in the pipeline and the air operated part, causes to pass flows the area to reduce, circulation drag increment, the overall system work is unstable, when serious, system knock off.(3)In the compressed air water vapor can congeal the waterdrop under certain pressure and the temperature, can cause the pipeline and the assistance part in the cold season because of freezes destroys.(4)In the compressed air dust has the abrasive action to the air operated part movement part, causes it attrition to be serious, affects their life.Thus it can be seen, establishes in the pneumatic system eliminates the water, eliminates the oil, the dust removal and dry and so on was mad the source refining equipment is extremely essential.Second, the air operated assistance partair operated part interior has many relative slippers, somewhat relative slipper depends on the seal packing collar to seal.In order to reduce transports the moving parts relatively the friction force, guaranteed the part movement is normal; In order to reduce the packing material the attrition, prevents divulging; In order to prevent the pipeline and the metal part corrosion, lengthens the part service life, guaranteed the good lubrication is extremely important.The lubrication may not divide into and spurts the mist lubrication for the oil lubrication.Some many air operated application domain does not allow to spurt the mist lubrication.If food and the drugs packing, in the transportation process, the oil granule returns to pollution food and the drugs; The oil granule can affect certain raw material for industry, the chemicals nature; The oil mist can affect the high-level spray coating surface and the electronic component surface quality; The oil mist can affect the measuring instrument true the survey; The oil mist can harm the human body health and so on.Therefore at present uses the mist lubrication to reduce gradually, does not give the oil lubrication already very popularly.Still did not use the rubber material for the oil lubrication to take the glide spot the seal, but sealed has the detention tank special structure, in order to memory lubricant.Other components should use not the easy rusty metal material or the nonmetallic material.For the oil lubrication part also may not to the oil use, once but gives the oil, does not have the midway to stop feed.At the same time, must prevent the condensed water enters in the part, in order to avoid flushes the lubricant.Not only has not saved the lubricating utensils and the lubricating oil for the oil lubrication part, improved the working conditions, moreover reduced the maintenance work load, reduced the cost.Moreover, also improved the lubrication condition.Its lubrication effect with the transit discharge, the pressure height, the tubing condition and so on all has nothing to do with.Also does not exist forgot refuels creates the breakdown the matter.The mist lubrication part has the oil mist and the centralism lubrication part two kinds.In (1) pneumatic system each kind of air valve, the air cylinder, the gas motor and so on, its movable part all needs to lubricate, but take the compressed air all seals the air chamber as the power air operated part, cannot use the general method oil injection, only can mix in by some method the oil in the air current, the belt to the place which needs to lubricate.The oil mist is this kind of kind of special oil injection installment.After it causes the lubrication oilatomization to pour into in the air current, enters the part along with the air which needs to lubricate. Refuels with this method, has the lubrication to be even, to be stable, the oil consumption few and does not need characteristics and so on big oil storage equipment.(2) air strainer is in the pneumatic system important link, is further filters the dust compressed air the impurity.The filter form are very many, the commonly used type includes: The disposable filter and two filter, have been requesting the high special occasion, may use the highly effective filter.99. In the pneumatic actuator system, called generally the filter, the oil mist, the pressure relief valve for air operated three association (or three big-ticket items), are in the pneumatic system the essential auxiliary unit.(3) silencerpneumatic circuit and the hydraulic pressure return route are different, it does not suppose the exhaust pipeline generally, after the compressed air use the direct platoon person atmosphere, because the gas rapidly inflation and forms the turbulent flow phenomenon, will have the intense exhaust noise.The exhaust speed and the power are bigger, the exhaust noise is bigger, may generally big 100~200dB.The noise harms people's physical and moral integrity directly, must eliminate or weaken.For the noise reduction, generally often installs the silencer in the pneumatic system air vent.The air operated functional elementair operated functional element is transforms in the pneumatic system the compressed air pressure energy the mechanical energy the part.It including air cylinder friendly motor.The air cylinder uses in realizing the straight reciprocating motion or swinging, was mad the motor uses in realizing the continual gyroscopic motion.First, The air cylinderair cylinder is in the pneumatic system the most commonly used one kind of functional element, compares with the hydraulic cylinder, it has the structure simply, pollutes, the movement few keen, responded quick, easy to make, easily to service, the cost low status merit, but because the thrust force is small, widely uses in the underloading system.(1) The air cylinder classifiedbasis air cylinder exploitation conditions are different, its structure, the shape, the type are very many, below introduces several kind of classifications.May divide into according to the compressed air function in the piston end surface direction: List function air cylinder and double-acting air cylinder.(2)Different may divide into according to the structure characteristic: Plunger-type air cylinder, plunger air cylinder, film air cylinder, leaf blade type oscillating cylinder, gear strip type oscillating cylinder and so on.(3) May divide into according to the air cylinder function: Ordinary air cylinder and special air cylinder.The ordinary air cylinder refers to the general plunger-type air cylinder, uses in the not special request the situation.The special air cylinder uses in having the special request situation, like was mad - - the fluid damping cylinder, the film air cylinder, flush are mad the air cylinder, the expansion and contraction air cylinder and so on.(4) According to installs the way differently to be possible to divide into: The ear place type, the flange type, sell the shaft type and the flange type and so on.(二)Common air cylinder principle of work and applicationThe ordinary air cylinder principle of work and the use are similar to the hydraulic cylinder, here no longer give unnecessary detail, below only introduces the special air cylinder.1. Is mad - - the fluid damping cylinderbecause the ordinary air cylinder works time, the compressed gas condensibility is big, when the outside work load change is big, the air cylinder appears “crawling” or “self-propelled” the phenomenon, the stability When therefore the equip ment precision is high, the air cylinder work stable request is also high, often uses was mad - - the fluiddamping cylinder is becomes by the air cylinder and the hydraulic cylinder combination, take the compressed air as an energy, by the hydraulic fluid took the control adjustment air cylinder velocity of movement the medium, the use liquid incompressibility control liquid displacement, adjusts the piston the velocity of movement, obtains the piston the steady motion.2. The film air cylinderfilm type air cylinder is replaces the piston by the thin film the air cylinder.It mainly by the cylinder body, the diaphragm, the diaphragm capsule and the connecting rod and so on the major parts is composed.Has the list to affect the type and the double-acting type.液压系统的构成液压系统的组成部风及其作用，如今在各种机械设备上广泛应用着的液压系统,使用具有连续流动性的油液,通过液压泵把驱动液压泵的电动机或发动机的机械能转换成油液的压力能,经过各种控制阀,送到作为执行器的液压缸马达中,再转换乘机械动力去驱动负载.构成这样的液压系统的各个组成部分及其作用.液压系统的特点和用途液压作为一种传动技术,有其突出的优点:能产生很大的动力,而且控制容易；可以用泵很容易地得到很高压力(20-30MPa)的液压油,把此压力油送入液压缸即可产生很大的力；能在很宽范围内无极变速；用控制阀对共给液压马达或液压缸的流量进行无级调整,即可随意控制其旋转或直线运动的速度；很容易防止过载,安全性大；尺寸小出力大,安装位置可自由选择；输出力的调整简单准确,可远程控制.液压系统的使用与维修，为了保证机械设备无故障的工作，必须遵循制造厂的使用维修要求。

外文原文Injection Molding ApplicationsIntroductionThe use of plastic tooling in injection molding occurs within the field of Rapid Tooling (RT), which provides processes that are capable of producing injection mold tooling for low volume manufacturing at reduced costs and lead times. Such tooling allows the injection molding of parts in the end-use materials for functional prototype evaluation, short series production, and the validation of designs prior to hard tooling commitment. The term Rapid Tooling is somewhat ambiguous – its name suggests a tooling method that is simply produced quickly. However, the term is generically associated with a tooling method that in some form involves rapid prototyping technologies.Investigation and application of Stereo lithography (SL) to produce mold cavities for plastic injection molding primarily began in the 1990s. Initially the process was promoted as a quick route to soft tooling for injection molding (a tool to produce a relative low number of parts). The advantages of this have been somewhat diluted as other mold production technologies, such as high speed machining, have progressed,but other unique capabilities of the process have also been demonstrated.Stereo lithography has several process capabilities that are particularly advantageous for injection mold tooling, but we should also appreciate that is accompanied by some significant restrictions. This chapter introduces several aspects of the process accompanied by a discussion of its pros and cons, along with examples of work by different parties (Fig. 1).Fig. 1 Injection molding insert generated by stereo lithography, shown with part1. Mold ProductionIn order to discuss the main topic; the direct production of mold cavities, it is first necessary to differentiate this from the indirect route. This is not a significant topic since SL merely provides the master pattern which, irrespective of the process used to produce this, has little influence on the subsequent injection molding.1.1 Indirect Mold ProductionThe indirect methods involve the use of an initial geometry that has been produced by SL. This geometry is utilized as a pattern in a sequence of process steps that translate into a tool which may be made of a material different to that of the pattern.Cast epoxy tooling represents a common indirect plastic RT method for injection molding. The process begins with a 3D model (i.e. CAD) of the part to be molded.Subsequently this model is produced by SL to provide a master pattern around which the mold will be formed. Traditionally, the part is produced solely without provision for parting lines, gating, etc. Such ancillaries are generated by manual methods (i.e. by fixing additional features to the part). However, the advent of easier CAD manipulation allows the model to be produced including such features.Once the complete master pattern has been produced, the mold halves are created by casting epoxy around the pattern, thus recreating a negative profile of the pattern.The epoxy may include fillers in attempts to improve strength and thermal properties of the mold. Such fillers include metal and ceramic particles in various forms.1.2 Direct Mold ProductionThe direct methods involve a SL system directly generating the tooling cavityinserts in its native material. The accuracy of the SL RP process results in insertsthat require few further operations prior to their use in injection molding. Like allRP related techniques the process is dependent on a 3D CAD model of the intended geometry. Unlike indirect techniques, the whole tool insert is generated by SL and so a 3D CAD representation of the whole tool insert is required. This involves creating negatives of the part to form the mold insert bodies, plus the provisions for gating, part ejection, etc. Previously, this extra CAD work would have represented more work required in the preparation. Such input is now minimized as modern CAD manipulation packages (e.g. Materialise’s Magics software) allow the automation of such activities. Once generated, the cavity inserts need to be secured in a bolster to withstand clamping forces and to provide alignment to the mold halves.It should also be mentioned that direct SL tooling for injection molding has also been referred to as Direct AIM. This term was given to the process by 3D Systems(SL system manufacturers) and refers to Direct ACES Injection Molding. (ACES stands for “Accurate Clear Epoxy Solid,” which is a SL build style).2. The Requirement of the ProcessThe introduction of rapid prototyping has allowed engineers and designers togenerate physical models of parts very early in the design and developmentphase. However, the requirements of such prototypes have now progressed beyond the validation of geometry and onto the physical testing and proving of the parts.For such tests to be conducted, the part must be produced in the material and manner (process) that the production intent part will be. For injection molding, this situation highlights the requirement of a rapid mold-making system that can deliver these parts within time and cost boundaries.Stereo lithography provides a possible solution to this by providing the rapid creation of a mold. A negative of the part required plus gating and ejection arrangements are generated in 3D CAD to create a tool that is fabricated by SL.This provides an epoxy mold from which it is possible to produce plastic parts by injection molding.Both Luck et al. and Roberts and Ilston evaluated SL in comparison with other direct RP mold-generating techniques for producing a typical development quantity of moldings. The SLmolding process was found to be a superior alternative for producing design-intent prototypes.It has also been noted that other alternative techniques involve additional steps to the process, therefore becoming less direct and not really RT. Other advantages of the process have been highlighted beyond the prototype validation phase. Since the tool design has been verified, the lead-time and cost involved in the manufacture of production tooling is also often reduced as the tool design has already beenproven.During the early years of SL it was never envisaged that such a RT method would be possible. At first glance the application of SL for injection mold tooling seems unfeasible due to the low thermal conductivity and limited mechanical properties of epoxy, especially at high temperatures. The glass transition temperature of SL materials available was only ~60_C, while the typical temperature of an injected polymer is over 200_C. Despite these supposed limits, successful results were achieved by SL users worldwide, including the Danish Technological Institute, Ciba Geigy, Fraunhofer Institute, the Queensland Manufacturing Institute, and Xerox Corporation.3. Mold Design ConsiderationsIn terms of the mold’s actual cavity design, relatively little information exists on the specific requirements of SL tooling. The early white paper issued by 3DSystems suggests the incorporation of a generous draft angle, but does not statethe amount and recommends the use of a silicone based release agent (every shot) in an attempt to prevent the parts sticking to the inserts. Work has been conducted that quantifies the effects of draft angle on the force exerted on SL tools upon ejection of a molding. It has been shown that an increase in tooling draft angle results in a lower force required to remove a part from the tool. However, the effect of draft angle variation on ejection force is minimal and little compensation for the deviation from intended part geometry caused by the addition or removal of material required to form the draft.Work has been conducted to establish the cause of core damage during molding.This found that damage was not related to pressure, but to the size of the core features. Smaller core features were broken due to a shearing action caused by polymer melt movement.Experimentation has revealed two modes of wear during the material flow within the cavity. These modes were abrasive at medium flow points (i.e. sharp corners),and ablative at highflow points (i.e. injection points). Other work has also emphasized the importance of the material flow influenced by mold design, identifying gating, and parting line shut off areas as points of potentially high wear.Fig. 2 Parts requiring different gating arrangements according to molding material4. injectionlaser system’s degree of curing is dependent upon the pulse frequency and the hatch spacing. Generally a continuous mode laser system allows for greater energy exposure.With respect to post-curing operations it should be noted that the amount of curing is not greatly affected by UV environment exposure. If thermal post curing is tobe used it should also be noted that a large majority of warpage occurs during this stage, which may be a concern if thin walled sections are in existence.The layer thickness of each build slice dictates the SL part’s roughness on surfaces parallel to the build direction. When this surface roughness is parallel to a mo lded part’s direction of ejection it has a resultant effect on the force required to remove the part from the mold which in turn applies a force to the insert which could result in damage. This surface roughness and the ejection forces experienced,correspond linearly to the build layer thickness. The solution is to re-orientate the SL build direction or employ a lesser layer thickness.4.1 Injection MoldingDuring molding, a release agent should be frequently used to lower the force experienced by the too l due to part ejection. In the author’s experience, a siliconelike agent is the most successful. Low-injection pressures and speeds should be used whenever feasible. Much lower settings are feasible in comparison to some forms of metal tooling due to SL heat transfer characteristics as discussed within this section.Early recommendations for SL injection molding stated that since damage occurs during part ejection it was appropriate to allow as much cooling prior to mold opening as possible. This reduced the tendency of the parts to stick to the inserts . The author has trialled this approach, which often leads to greater success, but the part-to-part cycle times are extremely long.More recent work has demonstrated that it is advantageous to eject the part as soon as possible (when part strength allows) before the bulk mass of cavity features have exceeded their glass transition point, when their physical strength is greatly reduced. This greatly reduces the heat transmitted into the tool and the cycle time for each part. Subsequently, it is also critical to monitor the mold temperature throughout the molding cycle to avoid exceeding the glass transition temperature (Tg) of epoxy, where tool strength is reduced. This entails each molding cycle beginning with the epoxy insert at ambient temperature and the part being ejected prior to Tg of the majority of the inserts volume being reached. This has been achieved in practice by inserting thermocouples from the rear of the cavity insert into the most vulnerable mold features such that the probe lies shortly beneath the cavity surface. Allowing the polymer to remain for sufficient time within the mold, while also avoiding critical Tg, is possible due to the very low thermal conductivity of SL materials.In addition, the low thermal conductivity of SL materials has been demonstrated to be advantageous in this application for injection mold tooling. It has been shown that the low thermal conductivity of SL tooling allows the use of low injection speeds and temperatures which are required due to the limited mechanical properties of SL materials. Traditional metal tooling needs these high pressures and speeds to prevent the injected polymer freezing prior to the mold completely filling.This is due to the rapid cooling of the injection melt when it comes into contact with the high thermal conductivity mold surface. Also, the SL tooling process has shown itself to be capable of producing parts that would not be possible under the same conditions using a metalmold. The thermal characteristics of SL tooling have made it possible to completely mold crystalline polyether ether ketone (PEEK), which has an injection temperature of 400_C (752_F).An equivalent steel mold would require a premolding temperature of about 200_C(392_F). An impeller geometry was successfully molded with vastly lower injection speeds and pressures were utilized, as shown in the Table 1 and Fig. 3.Table 10.1 Polyether ether ketone molding variables in SL mold vs. steel moldFig. 3 PEEK impeller molded by stereo lithography toolsA particularly illustrative account of the cooling conditions is shown in the above image. It can be seen that the polymer is primarily gray in color where it contacts SL surfaces indicating crystalline formation. Whereas where it comes into contact with the steel ejector pins it is brown, indicating localized amorphous areas. This is due to the difference in heat transfer of the two materials and hence the cooling rate experienced by the contacting polymer.5. Process ConsiderationsVarious polymers have been successfully molded by SL injection molding. These include polyester, polypropylene (PP), polystyrene (PS), polyamide (PA), polycarbonate,PEEK, acrylonitrile styrene acrylate, and acrylonitrile butadiene styrene.The greatest material limitation encountered has been the use of glass filled materials. All evidence indicates that the SL molding technique does not cope well with glass filled materials due to severe problems of abrasion to the SL cavity surface. This leads to poor quality, inaccurate parts, and undercuts in the cavity, which eventually result in the destruction of the SL insert. This abrasive nature has been quantified with a comparative SL molding study of PA 66 and PA 66 with 30% glass fiber content. The PA 66 enabled 19 shots prior to damage, while the glass filled variant allowed only 6 shots before the same level of damage was incurred . These findings are supported by work conducted by the author, with PA 66 with a 30% glass fiber content inducing high mold wear. However, it has been demonstrated that appropriate choices in mold design and process variables reduced the rate of wear. The use of appropriate settings has allowed the successful molding of a low number of partsas large as 165 _ 400 _ 48 mm (6.5 _ 16 _ 2 in.) with high geometrical complexity in PA66 with 30% glass content. The tool and parts are shown in Figs. 4 and 5.6 .Molded Part PropertiesDuring the course of my work with SL tooling, I have endeavored to investigate and pursue the most important aspect of tooling and molding; it is a means to an end.The end is the molded parts themselves. These are the products and if they are unsuitable, then tool performance is entirely irrelevant. Early work examining the resultant parts produced by the SL injection process described them only as being of a poor quality, effected by warping, and requiring a longer time to solidify due to the mold’s poor heat transfer producing a nonuniform temperature distribution. Other work also noted that using diffe ring materials in a mold’s construction (i.e. a steel core and a SL cavity) led to warping of the part due to the different thermal conductivities of the mold materials .Fig. 4 Large stereolithography molding toolFig. 5 Subsequent parts produced in polyamide 66 (30% glass fiber) The low thermal conductivity, and hence the low cooling rate, of the mold has a significant influence on the material properties of the molded parts. It was shown that parts from an epoxy mold exhibit a higher strength, but a lower elongation;around 20% in both cases .The differing mechanical properties of parts produced from SL molds as compared to thosefrom metal tools is also demonstrated in other work . This showed that the parts manufactured by SL molding had a lesser value of Young’s Modulus compared to those produced in a steel mold but possessed a greater maximum tensile strength and percentage elongation at break. These different part properties were attributed to a slow rate of heat transfer of the tool. This slow rate of heat transfer produces longer part cooling times giving a greater strength but less toughness.Research performed at Georgia Institute of Technology further investigated the mechanical properties of parts produced by the SL molding process. This work showed that noncrystalline and crystalline thermoplastic parts produced by the SL molding technique displayed differing mechanical characteristics than parts from traditional molds. Noncrystalline material parts possessed similar all-round mechanical properties compared to those produced in identical steel molds. However, crystalline thermoplastic parts demonstrated higher tensile strength, higher flexural strength, and lower impact properties compared to those manufactured in identical steel molds. More so with crystalline polymers than with amorphous materials, the mechanical properties of the plastic parts are influenced by the cooling conditions. These differing effects on mechanical properties have been demonstrated with PS (amorphous) and PP (crystal line). When the respective part’s mechanical properties were compared when produced by steel and by SL molds, the PS parts showed very little change while the PP parts demonstrated a great difference . In addition to differences in mechanical properties it has also been identified that some polymers exhibit different shrinkage according to the cooling conditions of the part during molding. These works indicate that crystalline polymers are susceptible to greater shrinkage when subjected to a slow cooling time.These differences in part properties have been attributed to the degree of crystallinity developed in the molded parts. This has been demonstrated by microscopic comparisons of parts produced by SL and metal alloy tooling. This revealed the spherulites (a crystal structure consisting of a round mass of radiating crystals) to be considerably larger from the SL tooling parts due to the higher temperatures and slower cooling involved during molding.In the wider field of general injection molding and plastics research, work has been conducted to identify and assess the variables that influence parts properties. These papers report a common theme, they identify the thermal history of the part to be a critical variable responsible for the parts resulting attributes. Recent work has shown that the slower molded part cooling imposed by SL tooling provides an opportunity to make some variations in the molding parameters for crystallinepolymers which allow the control of critical morphological factors (level of crystallinity). The subsequent level of crystallinity dictates many of the resultant part properties. The process modifications in this work were realized without changes to the machine, tool, or molded material (i.e. external cooling control, different polym er etc). This demonstrates a possible “tailoring” of molded part properties that would allow certain desirable part properties to be altered.These revelations demonstrate an advantage of SL tooling that was shown to not be possible in metal tooling. In summary, we must consider that the thermal characteristics of SL molds have an influence on the morphological structure of some parts. This may lead to a difference in the morphology of parts from SL tools as compared to those from metal tools. Such morphological differences can affect the shrinkage and mechanical properties of the molded part. When using SL tooling, one must decide if these differences are critical to the functionality of the part.7. ConclusionIn conclusion, SL molding is a viable process for some, but by no means all,injection molding tooling applications. Most important, is that the user should beinformed of the alternate design and processing requirements compared to conventional tooling, and be aware of the difference in resultant part characteristics, thus enabling realistic expectations and a more assured project outcome.注射成型应用摘要在快速成型领域中塑料模具在注塑成型时的应用，它在生产过程中可以制造出小批量生产降低成本和缩短时间的注塑模具。