模具快速成型技术的应用

Rapid prototyping technology and its application in die and mold manufactureZhao JieThe 09 Material forming and control engineering (1) class 0910121103 Abstract: Introduction of rapid prototyping (RP) technology, and its application in die mould manufacturing.RP technology is a computer aided design (CAD) and computer aided manufacturing (CAM) synthesis, is a broad application of technology, in the development of new products, parts of the many varieties of small batch production and die manufacturing and other fields are playing an increasingly important role in. Key word: CAD/ CAM; rapid prototyping; mold manufacturing0 IntroductionRapid prototyping (Rapid Prototyping, referred to as RP) is the late nineteen eighties quickly developed a kind of advanced manufacturing technology. The technique is different from the traditional processing methods, is the technology of 60 time NC after manufacturing field is another major breakthrough, advanced manufacturing technology is an important part of the group. RP technology integrated use of CAD/CAM technology, laser technology and material technology, in the absence of the traditional mold and fixture case, fast to create any complex shape and has a certain function of 3D solid model or parts. Rapid prototyping technology application will shorten the time to market for new products, save the new product development and mold manufacturing costs, widely used in aerospace, automotive, medical, electronics, home appliances, communication, toys, military equipment, Industrial Arts (sculpture), building models, mechanical and other fields.1 Rapid prototyping technology1.1 The history and development of rapid prototyping manufacturingRapid prototyping is also known as rapid manufacturing technology. This is a completely different with the traditional processing technology of the new processing technology, is a computer technology and new material technology the rapid development of the product. Times of the industrialization after industrial processing technology is a typical example of.This technology is a comprehensive technology of multiple disciplines and specialties of the latest achievements, thus starting point is high, development is very rapid also. nineteen eighties, American 3M company, UVP company and Japan's Nagoya Industrial Research Institute respectively put forward the application of UV curing photosensitive resin, stratified by scanning stacking 3D rapid manufacturing new concept. On 1988, the first commercially available stereo lithography rapid prototyping equipment available.Soon get high-end market recognition, prompting new models and equipment development, a variety of rapid prototyping systems have produced. From the development trend, the rapid prototyping system requirements in improving further, this basically behaves in thefollowing respects:(1)Equipment with higher resolution, can make traditional crafts to make complex, sophisticated products, such as a camera, a head, can be produced by a minimum size less than 0.5mm;(2)Product manufacturing precision, more close to the actual product;(3)Making faster;(4)Equipment automation rate is higher, not only can the automatic production, and can automatically monitor the production status, production process optimization, automatic fault diagnosis, so that the equipment reliability, maintenance more convenient;(5)To further reduce the production cost, energy conservation;(6)To reduce or eliminate the production of raw materials on environment pollution;(7)Develop a better and more suitable material, so that its strength and toughness to further improve.1.2 The principle of rapid prototyping technology and classificationRapid prototyping is a method based on the discrete accumulation forming thought digital prototyping technology, the principle is: through discrete, the complex three-dimensional manufacturing into an ordered series of low dimensional stack of manufacturing, the whole parts of the manufacturing process into orderly, simple unit manufacturing and combination process.According to different classification methods, rapid prototyping is divided into material form rapid prototyping, rapid prototyping manufacturing unit mechanism, energy rapid prototyping. Rapid prototyping technology the basic working process is: first by 3D CAD software to design parts of the CAD "electronic model", and then according to the specific process requirements, according to certain rules, the model is divided into a series of ordered unit, usually along the Z direction is divided into a series of two-dimensional plane, traditionally known as hierarchical or slice then, according to these discrete input information, processing parameters, the NC code generation. The prototype is in the NC code under the control of the sequential processing to generate each unit and the combined with each other, thus obtained with "electronic model of the corresponding 3D entity.".2 Common rapid prototyping process2.1 Stereo Lithography Apparatus (Stereo Lithography Apparatus, SLA)The photosensitive resin as raw material, using a computer under the control of the ultraviolet laser, with a predetermined prototype each section contour for the locus of point by point scanning, so that the scanned region of the resin layer to produce light reaction after curing, thereby forming a thin section. When a layer after curing, up (or down) the mobile table, just in the curing of the resin surface cloth to put a new layerof liquid resin, and then a new layer scan curing.The new cured layer bonded securely in the previous layer, so to repeat to the prototype. SLA technology is characterized by high precision, good surface quality, high utilization rate of raw materials, can be used in the manufacture of complex shape, the appearance of fine parts.2.2 Fused Deposition Modeling (Fused Deposition Modeling, FDM)The technique uses hot melt applicators, make the semi flow state materials according to the stratification of CAD data control path extrusion and deposition at the specified location is solidified, the layer-by-layer deposition after solidification physical prototype, removing the support bracket can be obtained, such as prototype parts.2.3 Selected Laser Sintering (Selected Laser Sintering, SLS)SLS is a method of adopting drum powder is spread into a thin layer, infrared board will be preheated to a temperature below the melting point of the powder slightly, and then use the computer to control the laser beam according to the prototype or parts of the section shape of the powder on the scanning platform. Laser beam scanning path, powder is sintered to form part of the physical model.The lifting work table a layer thickness, roller in sintered layer on top and a layer of powder, using a laser beam scanning sintering, repeat until the formation of a complete prototype layer sintering.Sintered powder can be made of plastic, metal, ceramic, composite wax powder and its. The technical characteristics of SLS is available material, simple manufacturing process, high precision, low cost.2.4 Laminated Object Manufacturing (Laminated Object Manufacturing,LOM) The process will be the film according to the CAD layered model the obtained data, using laser beams to one side coated with thermosol film cut into inner and outer contour to system prototype, and then a new layer superimposed on top of it, through hot pressing device for heating and below has been cutting layer bonded together, layer-by-layer cutting, gluing, until complete spare parts.3 The application of RP technology in model manufacturingRapid prototyping technology in die and mould manufacturing field is mainly used in production of mold design and manufacturing process used in the female mold, sometimes with rapid prototyping technology of direct manufacture mold.According to their different process is divided into the following 3 categories:3.1 The RP prototype directly used for manufacturing moldWith the development of RP technology, can be used for manufacturing the prototype materials more and more, performance has also been improved, some non-metallic RP prototype has better mechanical strength and thermal stability, so it can be directly used for mold. Such as the use of LOM process forming paper based prototype, as hard as a hardwood, can bear the high temperature of 200 DEG C, and can be machined, the appropriate surface treatment (such as spraying varnish, polymermaterial or metal), can be used as a sand casting mold, low melting point alloy mold, injection mold and trial use in investment casting wax molding die. Used as a sand casting mold, can produce 50~100 pieces of sand, used as a wax mold, injection of more than 100 pieces of wax. The use of selective laser sintering of polymer coated metal powder, comprising metal entity, then the polymer in a certain temperature decomposition disappeared, and then sintered at high temperature, the number of low density of sintered porous structure, can penetrate into the low melting point metal directly from metal mold. The mold used for molding parts, also can be used for small injection mould and die-casting mould, produced by this method the steel and copper alloy injection mold, life is amounted to tens of thousands of pieces, which can be used for mass production.In addition, if you use the metal material as FDM modeling material can also direct the formation of metal mold.3.2 The RP prototype mold manufacturing soft moldIf a part of the smaller quantities (dozens to thousands of pieces), are available for non steel materials at relatively low cost soft mould. The process for the use of RP technology in the production of the prototype parts, and then to RP prototype as master mold, burning wax injection, silicone rubber, epoxy resin, polyurethane and other soft material, a soft mold.Wherein, wax pattern for investment casting, silicon rubber, epoxy resin, polyurethane, used for small batch production with mold or low melting point alloys (such as zinc alloy, aluminum alloy) die casting.These soft material has good elasticity, copy and certain strength, in the casting of complex mold, which can greatly simplify the mould structure design, and easy to release. As with silicon rubber mold can not consider adding to copy the draft, the basic will not affect the size precision.Room temperature vulcanized silicone rubber has good cutting performance, with a thin blade can easily be cut, and the section between very closely and, therefore, to use it to copy the mold, can't be divided into upper and lower mold, casting a soft mold, again by a predetermined parting surface will open, remove the parent die die, die, get on.3.3 The RP prototype mold manufacturing hardware mold3.3.1 Ceramic mould precision casting dieIn the production of metal injection mold can be used in this method.The process is: RP prototype to copy soft mode to remove mold in soft mould pouring or sprayed ceramic slurry, pouring the metal cavity surface polishing, join the gating system and the cooling system of injection mold, mass production.3.3.2 Metal spray coating moldIn the RP prototype or transition model for the mold surface, arc or plasma spraying mist metallic, forming a metal layer, remove the female mold, the metal shell cast metal matrix composite material back filling or epoxy resin, forming a hard backing,after processing metal surface, a hard backing mold.This method is simple to operate, production of the mold good mechanical properties, also easy to ensure precision, can make the work pressure high die, die service life can amount to 1000～30000 pieces.3.3.3 Chemically bonded ceramic moldTo the RP prototype mold making a soft mold, using soft mold rapid fabrication of ceramics die.The process is: rapid prototyping manufacturing paper mold, pouring silicone rubber, epoxy resin, polyurethane and other soft material to form the soft mode, remove the female die, in the soft mold casting chemically bonded ceramic cavity, in cured at 205 ℃ for CBS cavity, the cavity surface polishing, join the gating system and cooling system, small batch production of injection mold.The ceramic mold life of about 300.4 ConclusionRP technology is a rising near new and high production technology, after ten years of development, equipment and materials have made great progress, but at present because the technology is still relatively high cost, plus the parts precision, strength and durability can't meet the requirements of users, restrict the popularization of this technology promotion. With the development of technology, technology will be further perfect, development, in more and more applications.RP technology and application in die mould manufacturing a wide range of applications, it will greatly promote the mold manufacturing technology, to improve product quality, accelerate the development of new products as well as reducing tooling costs and have positive significance.Reference[1] Gao, Chen Xiangdong, Ren Xiaojian. Rapid prototyping manufacturing technology in industrial production in the use of [J]. Machine Mechanical process engineer, 1999,1: 12- 13.[2] He Youyi.CAD/ CAM technology and application [M]. Beijing: Mechanical Industry Press, 2002,7.[3] Andreas, Gebhard. Rapid prototyping technology [M]. Beijing: Chemical Industry Press, 2005: 237.[4] Liu Li paper mold and its application in casting process [J]. foundry technology, 1997,2:38- 39[5] Wang Shujie technique for rapid mould making new progress [J]. die and mould technology,1998,1: 40- 48.。