Micro-injection molding with the infrared assisted mold heating system
Ming-Ching Yu a, Wen-Bin Young a，and Pe-Ming Hsu b
a Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan, ROC
b Department of Chemical Engineering, Far East University, Tainan, Taiwan, ROC
Received 26 October 2006; revised 12 January 2007; accepted 6 February 2007. Available online 17 February 2007.
Abstract
Mold temperature and packing pressure are the major factors that affect the process of micro-molding.The mold temperature was found to be the crucial factor that controls the success of the complete filling. In micro-injection molding,the mold temperature has to be close to the glass temperature to ensure a good replication of the micro-features. This study is to investigate the effect of infrared mold surface rapid heating system on the micro-injection molding.The micro-feature was defined by the UV lithography technology and transfer to the nickel mold insert by micro-electroforming. An infrared heating system is designed and built to heat the mold surface dynamically. The infrared heating system raises the mold cavity temperature locally to facilitate the replication of the micro-structure. The results show that mold cavity surface must be heated to above a critical temperature before molding.The critical temperature is close to the glass transition temperature and it decreases with the increase of the packing pressure. For mold temperature in 80 °C, heating more than 10 s can result in a complete filling of the micro-feature used in this study.
Keywords:Micro-injection molding; IR heating; Micro-features; Injection molding
Article Outline
1. Introduction
2. Infrared heating system
3. LIGA-Like process for mold insert
4. Molding experiment
5. Results and discussion
6. Conclusions
References
1. Introduction
In recent years, fabrication of micro-components has gained increasing attention in industry and academia. Micro-molding of polymer-based materials are favored because of low cost, good biocompatibility, high optical clarity, high impact strength, and ease of mass production. Most of the applications are concentrated on the fields of micro-optics and micro-fluidics. Micro-injection molding can be designated to the fabrication of components with micro-features or components with volumes in the range of milligrams.
In micro-molding of components with micro-features, the ability for the polymer melt to flow into the micro-channels is a crucial factor for successful molding. In this case, the molded volume is about the same as the conventional molding. The penetration distance of the polymer into the micro-structure depends on the flow rate and the cooling rate of the micro-features, which is function of the geometric dimension. In the range of 10–100 μm features, the cooling rate of the polymer melt is so quick that the flow length is limited to a very short distance under the usually mold temperature. For feature in the micron/submicron range or with a high aspect ratio, it is difficult to force the polymer to completely fill the geometry.
It has been reported that mold temperature and packing pressure were the major factors related to the micro-molding [1], [2], [3]and [4]. The mold temperature was also found to be the crucial factor that controls the success of the complete filling. In the micro-molding process, polymer does not fill in the micro-feature during the filling stage. As the polymer melt flows near the micro-feature, it tends to bridge over instead of flowing in since the pressure at the flow front is too low for it to enter the micro-feature. Most of the filling of the micro-feature is done in the packaging stage. Therefore, the mold must be kept at a high enough temperature to allow complete filling.
From the reported experimental results in literatures, the mold must be maintained near the glass transition temperature during the filling and packaging stages, and lower to below the deflection temperature in the cooling stage. This is not an easy task for managing the mold temperature without increasing much of the cycle time and energy consumption. Direct heating and cooling of the entire mold is not an economic option due to the large heat mass of the mold. Local heating of the key features or the mold surface was reported to be a better way. Yao and Kim [5] reported a rapid mold surface temperature variation by coating heat conducting and insulting layers on the mold surface. The heat conducting layer can conduct the electrical current to raise the mold temperature quickly while the insulting layer can keep the heat from the mold base. Chen et al. [6] uses induction heating of a mold plate to raise the mold temperature. Saito and Satoh [7] used the direct infrared heating on the polymer to control the polymer temperature. It results in molded product with low molecular orientation in the surface region. This study is to investigate the effect of infrared mold surface rapid heating system on the micro-injection molding. The micro-feature was defined by the UV lithography technology and transfer to the nickel mold by micro-electroforming.
2. Infrared heating system
As mentioned earlier, increase of the mold temperature can facilitate the filling of the micro-structure in micro-injection molding. In this study, an infrared heating system is designed and built to heat the mold surface dynamically. At each cycle, the infrared heating system is located between the two mold halves and heats the specific areas of the mold surface. As the mold surface reaching the desired temperature, the heating system is removed and the mold closes for injection. The entire mold temperature is controlled by the running fluid in the cooling system. The infrared only heats the local mold surface. After removing the infrared heating system, the locally heated area starts to cool down to the mold temperature. The temporary increase of temperature in local area will enhance the ability of polymer filling flow in the filling and packing stages.
A CAD design of infrared heating system is shown in Fig. 1. The system is mounted on the mold half that is fixed on the injection platen. As the mold is opened, compressed air will drive the cylinder to locate the infrared lamps between the mold halves to heat the mold surfaces. The infrared heating system has two units including heater and controller. The heater composes of four
1 kW halogens infrared lamps and two lamp covers. Each lamp cover contains two lamps to heat a mold half. The lamp cover is made by machining a semi-spherical cavity on an aluminum block (AL-7075). After hand polishing, the lamp cover is painted and electrical vapor deposition of aluminum to increase its reflectivity. The lamp cover and entire assembly of the heating system is shown in Fig. 2. The control unit is to set the motion of the air cylinder and the heating time. As the heating system is turned on, a magnetic air valve will open to allow the air cylinder to drive the heater to the position between the mold halves and start to heat the mod surfaces. At the same time, a timer is set to count the heating time. As the time is up, the air valve is switched to drive the air cylinder to retrace the heater. The mold halves are then close for injection.
Fig. 1. The CAD design of the infrared heating system installed on the mold.
Fig. 2. (a) The lamp cover installed with two infrared lamps (b) entire assembly of infrared heating system.
3. LIGA-Like process for mold insert
The mold insert has micro-features of two sets of parallel gratings that interleave together. The dense area has parall el gratings 6 μm in pitch while the coarse area has gratings 12 μm in pitch. The original micro-pattern was defined on a glass substrate and then transferred to a mold insert by electroforming. Photoresist is spun coating on a glass substrate, and then exposed through a patterned mask under the UV light. After developing, the region exposed will be washed out to form micro-structures in the photoresist. A seeding layer composed of chromium and gold is deposited on top of the photoresist by a PVD process before the electroforming. The opened pattern on the substrate is electroformed with nickel. After that, the mold insert with patterned
micro-structures is removed from the substrate.
A positive photoresist, AZ 5214E, was used in this study. Before spin coating, the substrate was washed first in an ultrasonic cleaner for 5 min followed by a rinse with DI water. After drying, it is spun with HMDS first and then AZ P4620 followed by the pre-bake, exposure, and post-exposure bake to image the pattern on the photoresist. The roughness of the glass substrate is about 0.016 μm. The spun thickness is about 2.65 μm with roughness in the range of 0.02 μm. The photoresist is pre-baked on a hot plate under 90 °C for 1.5 min. After that, UV exposure is performed with a mask aligner under 365 nm wavelength and 80 mJ/cm2exposure energy. After exposure, this positive photoresist can be developed by MIF300 for about 40 s. A post exposure bake is performed on a hot plate under 120 °C for 2 min to further cure the photoresist.
Electroforming on the substrate with patterned photoresist will cast nickel on the substrate to form the mold insert. A seeding layer composed of chromium in 300 ? and gold in 500 ? was deposited on top of the photoresist by an Electron Beam Gun Evaporation Deposition process. A commercial nickel sulfamic acid was used as the electrolyte. The forming process is performed under three stages of electrical density (shown in Table 1) with mechanical stirring, and the temperature is controlled in the range of 42–43 °C. After electroforming, the resulting mold insert with micro-structures is shown in Fig. 3.
Table 1.
The current densities used in different stages of the forming process
Current
(mA) Current density (A/dm2)
Thickness
(μm)
Time
(h)
First15.70.710011.6 Secon
d
96.7 4.35009.5 Third157.57.0100011.6
Total160032.7
Fig. 3. The electroformed mold insert and the micro-structures.
The electroformed micro-structure was inspected with a scanning probe microscope of AFM (Atomic Force Microscopy CP-II from Veeco Instruments) to check the dimensions. Fig. 4 shows the measured profile of the micro-feature of trenches at the dense and coarse areas on the mold insert. The micro-features have a negative draft angle at the sidewall in most of the profile. This will facilitate the demolding process after injection molding. The height of the micro-features is about 2.62 μm with about 0.10 μm variations.
Fig. 4. The surface profiles of the micro-structures on the mold insert.
4. Molding experiment
A two-plate mold with two rectangular mold inserts fabricated by the LIGA-Like process described previously was used in this study. Fig. 5(a) shows the mold with the mold inserts installed. The two mold cavities are in the same dimension of 20 mm ×20 mm ×0.65 mm. Material used in the molding experiments is polymethyl methacrylate (PMMA) CM-205 (from Chi Mei Corporation, Taiwan). Two thermal couples from Priamus were flush mounted in the mold cavity to measure the polymer temperature variation during the molding cycle. Notice that the thermal couple is mounted on the cavity side without micro-patterns. The measured temperature is not actually the temperature of micro-pattern area. The design of the infrared heating system is the same at both sides to ensure the same heating effects. Since the heating in intended to the surface region, the temperature in both sides is assumed to be close to each other. The base process conditions used in the molding experiments are as following: melting
temperature is 270 °C, packing pressure is 40 bar, packing time is 10 s, mold temperature is 70 °C, plunger speed is 50 mm/s, and cooling time is 20 s. Different process conditions and mold surface heating time were used in the molding experiments. Fig. 5(b) shows the molded product with the arrangement of sprue and runner system. Fig. 6shows the 3D microscope images of the micro-structure cross-section of the molding product. With the product, the center position was chosen for the replication accuracy check. The filling height and profile of the micro-structure at the dense area were measured by the AFM. In the molding experiments, several shots were run before samples could be selected for measurement in order to have stable injection parts. The corresponding measured position is also shown in Fig. 6. For the molded part, the filled micro-features in different positions are measured to check the molding uniformity. The variation is about 0.2 μm for filled part and does not show obvious trend in the studied cavity size.
Fig. 5. (a) Two-plate mold with mold insert installed (b) micro-feature of the molded component.
Fig. 6. AFM images of the molding replication micro-structure on the molding product.
5. Results and discussion
In order to study the effect of the mold surface infrared heating on the degree of micro-structure replication, different heating times from 10 to 40 s in 10 s increment are used in the experiments. The installed thermal couples can measure the temperature variation of the polymer during the entire molding cycle. A typical temperature profile during a cycle is shown in Fig. 7. As activating the infrared heating system, the mold temperature at the cavity is raised to a higher temperature depending on the heating time. In Fig. 7, the mold surface temperature is raised from 40.5 to 75 °C in 10 s using 4 kW infrared heating power. This method has a comparable heating rate as
the electromagnetic induction heating reported by Chen et al. [6]. However, the heating rate is lower than the method by heating the surface coating layer reported by Yao and Kim [5]. Since the cavity dimension is not large, only one point of temperature in the cavity can be measured. The infrared lamp is designed to be larger than the mold cavity to ensure a uniform heating of the cavity area. As reported by Chang and Hwang [8], the central area of the heating region can have quite uniform temperature distribution in the infrared heating.
Fig. 7. A typical temperature profile of the polymer during a molding cycle.
After cease of heating, the time it takes to remove the heating system and close the mold for injection is about 5 s in our system. During this period, the mold cavity temperature will drop slightly due to the natural cooling. The measured temperature will again rise as the injection polymer melt reaching the thermal couple. At the following packing and cooling stages, the cavity temperature will approach the mold temperature. The cycle completes as the cavity temperature falls below the deflection temperature and the mold is opened. It is the temperature before the filling, which affects the degree of replication in the molding process.
The mold temperature is set to 60 °C initially, and molding experiments are performed for different heating times. Fig. 8shows the temperature profile and the cross-section of replicated micro-structure under 10 s of infrared heating. Apparently, the replication is not complete since the height of the micro-structure is about 1 μm that is less than the feature on the mold insert. As the heating time is increased to 30 s, the replication turns out to be complete. The corresponding temperature profile and the cross-section of replicated micro-structure are shown in Fig. 9. Notice that, in this case the cavity temperature after mold closed is about 110 °C before the polymer filling. This temperature is higher than the glass transition temperature of PMMA. It is known that the replication of the micro-structure can be complete as the mold temperature is raised above the glass transition temperature of the molding material. The infrared heating system raises the mold
cavity temperature locally to fulfill the condition for the complete micro-structure replication.
Fig. 8. The temperature profile of the polymer during a molding cycle and a cross-section of the replicated micro-structure (mold temperature, 60 °C; heating time, 10 s).
Fig. 9. The temperature profile of the polymer during a molding cycle and a cross-section of the replicated micro-structure (mold temperature, 60 °C; heating time, 30 s).
As already shown previously, the local cavity temperature before mold filling must be raised above the glass transition temperature to ensure a complete replication. This is related to the time for the infrared heating with specified power. The mold temperature is another factor that affects the local cavity temperature after specific time of heating. Fig. 10shows the height o f the replicated micro-structure after molding under different mold temperatures and heating times. Under the 40 °C mold temperature, heating the mold surface up to 40 s is not able to bring the temperature to high enough for complete replication. The time required to raise the cavity temperature to a point for complete replication is less for higher mold temperature as expected. It only takes 10 s of infrared heating to achieve a complete replication in the molding under 80 °C mold temperature.
Fig. 10. Heights of the replicated micro-structure after molding under different mold temperatures.
(a) Mold temperature, 40 °C; (b) mold temperature, 60 °C; (c) mold temperature, 80 °C.
Table 2lists all the molding results in this study using different process parameters. For the studied cases, the replication can be divided into three phases, namely partially filled, partial shape, and completely filled. For the partial shape, the filled height of the micro-structure reaches the mold feature but the shape is not complete. It can be observed that the cavity temperature must be raised above a critical temperature, 108 °C (near the PMMA glass transition temperature), to ensure a complete replication of the micro-structure.
Table 2.
The molding results for different mold temperature and infrared heating time
Mold temperature (°C) Heating time
(s)
Cavity temperature before filling
(°C)
Filled height
(μm)
40No400.0576
1064.50.2286
20800.6226
3091 1.137
4096 1.261
50No500.1073
10750.3954
2090 1.002
3098 1.682
40108 2.518 ■
60No600.2373
1085 1.008
2098.5 2.460
30109 2.518 ■
40117 2.511 ■
70No700.4111
1095 1.661
20110 2.513 ■
80No800.763
10104 2.495 ●
20121 2.555 ■
() Partially filled, (●) partial shape (enough height, not complete shape), (■) completely filled.
In the previous cases, the molding is performed under a packing pressure, 40 bar. If the packing pressure is increased, the replication can be completed with a less infrared heating time. For the case of 60 °C mold temperature and 20 s heating time, the filled height with respect to the packing pressure is shown in Fig. 11. As the packing pressure is increased from 40 to 70 bars, the micro-structure can also be completely replicated under the 60 °C mold temperature and 20 s
heating time. In this case, the cavity temperature before mold filling is 98.5 °C that is lower than the critical temperature, 108 °C, concluded from the previous discussion. However, this temperature is still close the glass transition temperature. If the cavity temperature before mold filling is far lower than the glass transition temperature, the replication cannot be completed by increasing packing pressure. Therefore, it can be concluded that the critical temperature must be close to the glass transition temperature and it decreases with the increase of packing pressure.
Fig. 11. Heights of the replicated micro-structure after molding under different packing pressures (mold temperature, 60 °C; heating time, 20 s).
6. Conclusions
This study is to understand the effect of infrared mold surface rapid heating system on the micro-injection molding. The micro-feature was made with the UV lithography technology and the nickel mold insert was made by micro-electroforming. An infrared heating system is designed and constructed to heat the mold surface dynamically. At each cycle, the infrared heating system is located between the two mold halves and heats the specific areas of the mold surface. The infrared heating system raises the mold cavity temperature locally but is still able to replicate the micro-structure completely. The mold cavity surface must be heated to above a critical temperature before molding. The critical temperature is close to the glass transition temperature and it decreases with the increase of packing pressure. For mold temperature in 80 °C, heating more than 10 s can result in a complete filling of the micro-feature used in this study.
References
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小学英语总复习 小学英语介词总结 介词（Preposition） 一、概述 介词是英语中很活跃的词，一般置于名词之前。它常和名词或名词性词语构成介词短语。同一个介词常和不同的词语搭配形成固定搭配，表示不同意义。 二、常用介词的基本用法 at ①表示时间：I go to school at seven every day 我每天早上7点去上学。 ②表示在某一具体地点：He is standing at the bus stop 他站在公共汽车站。 ③表示动作的方向、目标：Let me have a look at the picture 让我看看这幅图。 ④用于某些固定搭配：at once 立刻、马上at last 最后 at the same time 同时at first 开始时 not at all 一点也不 about ①表示大约时间：It’s about six o'clock now. 现在大约6点钟了。 ②表示地点；在……周围：Everything about me is so beautiful 我周围的一切都那么美好。 ③关于，对于：We are talking about the news. 我们正在谈论新闻。 after ①在……之后：After dinner I watch TV. 晚饭后我看电视。 ②在……后面：He came into the room after me. 他在我后面进了房间。 behind ①在……之后：There is a bike behind the tree. 树后有一辆自行车 ②比……晚，迟于：The train is behind time. 火车晚点了 by ①在……旁：He is sitting by the bed. 他正坐在床边。 ②到……时候：We have learned three English songs by now. 到现在为止，我们已经学会了三首英文歌曲。 ③以……方式：I go to school by bus. 我乘公共汽车去上学。 ④用于某些固定搭配：one by one 一个接一个by the way 顺便说一句
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?小学常见介词： 1.on (1) 在------上面The book is on the desk. (2) 在------（哪一天/星期）What do you do on Wednesday? (3) 在------（月、日）My birthday is on August 2nd. 2. in （1）在------里面The pens are in the pencil-box. (2)在------（哪一年/月）His birthday is in October. He worked here in 1992. (3 ) 在------（地方）He works in Dongguan. (4 ) 在------之内What are you going to do in 20 years? (5 ) 在------（早上、下午、晚上） I do morning exercises in the morning every day. I usually play basketball in the afternoon. I often do my homework in the evening. 3. under 在------底下There is a ball under the bed. 4. near
在------附近There is a book shop near our school. 5. in front of 在------前面 A boy is standing in front of the house. 6. beside 在------旁边 A football is beside the door. 7. next to 紧挨着There is a bus station next to No. 13 Middle School. 8. over 在------正上方A bridge is over the river. 9. on the left 在------左边The bookstore is on the left. 10. on the right 在------右边The hospital is on the right. 11. before 在……之前Mike sits before me. 12. after 在------以后He went home after school. 13. in the middle
小学介词常用示例 表示时间的介词称为时间介词.表示时间的介词有：at, on, in, before, after 等. 一、at, on和in ① at 表示：（在（某时刻、时间、阶段）,在……岁时） My cousin joined the army at fifteen. 我表哥十五岁参的军. ② on 表示：在（某日）,在周末,在……节日 He was born on the 15th of August in 1769. 他出生于1769年8月15日. ③ in 表示：在……事后,在……期间,在……年/月 She went to America in 2000. 她2000年去了美国. at, on 和in 作时间介词的比较： ① at 表示具体时间点. ② on 后可以跟表日期、星期、节日的词,还可以指具体某一天的早、中、晚. ③ in 泛指一天的早、中、晚,还可以表示一段时间,如：周、年、月、季节等. 二、before和after ① before 表示：在……之前 before eight o’ clock 八点之前 Spring comes before summer. 夏天之前是春天. ② after 表示：表示……之后 after lunch 午饭之后 Come to my office after school. 放学后请来我办公室. 表示做某事的方法、手段的介词有by, with, in, at, on. 一、by by表示：用,以,靠,通过……方式.by表示手段时后接动作或制作方式.“by + 交通工具”表示交通方式. by bike 骑车 by bus 坐公车 by taxi 搭出租 by train 坐火车 by ship 乘船 by air 坐飞机 Linda usually goes to work by subway. 琳达通常做地铁上班. She makes a living by teaching. 她考教书谋生. 二、with with 表示：用,以.with表示手段时,后接工具、材料或具体内容. write with a pen 用钢笔写 eat with knife and fork 用刀叉吃 see with one’s eyes 用眼睛看 I killed the fly with a swatter. 我用苍蝇拍打死那只苍蝇. She cut the cake with a knife. 她用刀切开了蛋糕.
小学英语常用介词用法 摘要：英语介词并不很多，但其用法灵活多样。掌握常用介词的用法及常见的介词搭配，是学习英语的重点和难点。 关键词：英语介词用法 介词是英语中一个十分活跃的词类，在句子的构成中起着非常重要的作用。介词也是英语中的一个最少规则可循的词类，几乎每一个介词都可用来表达多种不同的含义；不同的介词往往又有十分相似的用法。因此，要学好介词，最好的方法就是在掌握常用介词的基本用法的基础上，通过广泛阅读去细心地揣摩，认真地比较，归纳不同的介词的用法，方能收到良好的效果。那么，什么是介词呢？小学常用的介词都有哪些以及它们的用法？ 一·介词 1 介词的含义 介词又叫前置词，是一种虚词，用来表明名词，代词（或相当于名词的其他词类，短语或从句）与句中其他词关系的词。介词不能重读，不能单独做句子成分，必须与它后面的名词或代词（或相当于名词的其他词类，短语或从句）构成介词短语，才能在句子中充当一个成分。介词后面的名词，代词或相当于名词的部分称为介词宾语，简称介宾。 2介词的分类 1）根据介词的构成形式，可将介词分为简单介词，合成介词，双重介词，短语介词四类。而小学英语中涉及到的介词仅为简单介词和一些短语介词，如：after（在……之后），against（反对），along（沿着），among（在……之中），at（在），behind（在……后面），near（在……附近），into（在……里），in（在……内，用，戴），from（从），for （为，给），except（除……之外），by（乘，在，由，到），on the left (在左边),on the right (在右边)······ 2）根据介词的意义，可将介词分为表示空间关系的介词，表示时间的介词，表示原因，目的的介词，表示手段的介词和其他介词。如：表示时间的介词in，on，at，表示方位的介词in，on，to······下文则主要是从介词的意义方面来讲介词的用法。 二·小学常用英语介词 1课文中常出现的介词 1）about（关于，大约）：a book about animals 一本关于动物的书。 2）above（在……上面）：a map above the blackboard 黑板上方的一张地图，above all 首要的是。 3）across（穿过，跨过）：a bridge across the river 跨过河的一座桥 4）after（在……之后）：after breakfast 早饭后，after school 放学后，after class 课后 5）against（反对）：play against them 跟他们比赛。 6）along（沿着）：plant trees along the lake 沿着湖边植树。 7）among（在……之中）：among the workers 在工人们中间，among the trees 在树丛中。 8）at（在）：at home在家，at school 在学校，at work 在工作。 9）before（在……之前）：before class 课前，before lunch 午饭前 10）behind（在……后面）：behind the house 在房子后面，behind the door 在门后。 11）near（在……附近）：near the river 在河边，stand near the door 站在门旁。 12）into（在……里）：come into the classroom 进入教室，fall into the water 掉进水里
常见介词及用法 (一)表示时间的介词 1.英语里最常见的时间介词有：at, in, on, before, after和from。 2.at , in和on这三个词都表示时间。 ?at主要指具体的钟点：at half past eight 在八点半 ?in一般指某一段时间：in January 在一月份 ?on指具体在某一天：on Monday 在星期一 3.before和after表示时间的先后顺序。 ?before表示“在……之前”。 You should wash your hands before eating. 吃饭前你应该洗手。 ?after表示“在……之后”。 They often play basketball after dinner. 他们放学后经常打篮球。 4.from作时间介词含有“从……开始”的意思，常和to连用，组成 “from…to…”的结构，表示“从……到……”的意思。 We go to school from Monday to Friday. 我们从周一到周五上学。 (二)表示方位的介词，也就是表示位置和地点的介词。 1.小学阶段常见的方位介词有：on, in, at, under, over, above, below, about, around, between等。 2.on, over和above 这三个词都有“在……上面”的意思，但它们所表示的方位还是有些不同。 ?on表示两个物体的表面相互接触。如： There is a book on the desk. 桌上有一本书。 The boy is sleeping on the desk. 那个孩子睡在地上。 ?over表示“在……的正上方”,两个物体表面没有接触。如： There is a light bulb over my head. 在我头顶上有一个灯泡。 ?above表示两个物体中一个在另一个的上方，如： The plane is flying above the clouds. 飞机上云层上飞行。
常用介词的基本用法 1、at ①表示时间：I go to school at seven every day 我每天早上7点去上学。 ②表示在某一具体地点：He is standing at the bus stop 他站在公共汽车站。 ③表示动作的方向、目标：Let me have a look at the picture 让我看看这幅图。 ④用于某些固定搭配：at once 立刻、马上at last 最后 at the same time 同时at first 开始时 not at all 一点也不 ; 2、about ①表示大约时间：I's about six o'clock now. 现在大约6点钟了。 ②表示地点；在……周围：Everthing about me is so beautiful 我周围的一切都那么美好 ③关于，对于：We are talking about the news. 我们正在谈论新闻。 3、after ①在……之后：After dinner I watch TV. 晚饭后我看电视。 ②在……后面：He came into the room after me. 他在我后面进了房间。 4、behind ; ①在……之后：There is a bike behind the tree. 树后有一辆自行车 ②比……晚，迟于：The train is behind time. 火车晚点了 5、by ①在……旁：He is sitting by the bed. 他正坐在床边。 ②到……时候：We have learned three English songs by now. 到现在为止，我们已经学会了三首英文歌曲。 ③以……方式：I go to school by bus. 我乘公共汽车去上学。 ④用于某些固定搭配：one by one 一个接一个by the way 顺便说一句 6、for ] ①为，给，替：I'll make a card for my teacher. 我要给老师做张卡片。 ②由于：Thank you for helping me. 谢谢你帮我。 ③表示给（某人）用的：There is letter for you. 这儿有你一封信。 7、in ①在……里面：The pencil is in the desk. 铅笔在课桌里。 ②在一段时间里：We have four classes in the morning. 我们上午有四节课。 ③用，以：What's this in English 这用英语怎么说 ④在某一年份，季节，月份：in 2002, in spring, in January 【 ⑤表示状态，服饰：Helen is in yellow. 海伦身穿黄色衣服。 ⑥在……方面：He is weak in English. 他的英语不行。 ⑦用于某些固定搭配：in front of 在……前面 in the end 最后
小学常见介词: ⑴在-——上面The book is on the desk. (2) 在 --- (哪一天/ 星期)What do you do on Wedn esday (3) 在 --- (月、日) My birthday is on August 2nd. 2. in (1) 在--- 里面The pens are in the pen cil-box. ⑵在——(哪一年/ 月)His birthday is in October. He worked here in 1992. (3 ) 在----- (地方) He works in Don ggua n. (4 )在 ----- 之内What are you going to do in 20 years (5 ) 在------ (早上、下午、晚上) I do morning exercises in the morning every day. I usually play basketball in the afternoon. I ofte n do my homework in the eve ning. 3. un der
在-- 底下There is a ball under the bed. 4. near 在-- 附近There is a book shop near our school. 5. in front of 在-- 前面A boy is standing in front of the house. 6. beside 在-- 旁边A football is beside the door. 7. next to 紧挨着There is a bus station next to No. 13 Middle School. 8. over 在-- 正上方A bridge is over the river. 9. on the left 在-- 左边The bookstore is on the left. 10. on the right 在-- 右边The hospital is on the right. 11. before 在... 之前Mike sits before me. 12. after 以后He went home after school. 13. in the middle
系表+介词 Be angry about /at/ with 对.....感到生气Be sorry about to 对.....感到抱歉Be pleased with /at...... 对.....感到高兴 Is famous as... 以.....身份/职业而闻名Is famous for... 以........而闻名 Be Interested in... 对.....感兴趣 Be poor / Weak in... 在......方面薄弱Be afraid of....... 害怕........ Be sure of 对........有把握 Be sure about对........有把握 Be polite to... 对........有礼貌 Be Friendly /kint to... 对.....友好 Be good for 对.....有益Be Strict in... 对......严格（对事）Be Strict with ....... 对..........严格（对人）Be Good at..... 擅长于....... Be surprised at... 对........感到惊讶 Get ready for... 为.........做好准备 Be rich in... 在.........方面富有 be different from...与..........不同 Be fond of 喜欢.......... Be proud of...... 为..........而自豪 Be rude to....... 对..........粗鲁 Be kind to.../be good with善待.......... Be busy with.......... 忙于.......... 介词+名词 At night 在夜间 at once 立刻 At home在家 After school 放学后 All in all / In general 总的来说 by the lake 在湖边 By oneself / alone 独自 for example 例如 At class 在上课 On time按时 To one's surprise 令某人惊讶的是On foot 步行 On business / A business travel出差 At noon 在中午at first当初、起先 At work 在上班 after all 毕竟 By the way 随便问一下 By the way 到现在为止 By day在白天 For fun / To make fun of 开玩笑地 In time 及时 In Surprise 惊讶地 In tinge及时 In town 在城里 By train / car / bu s 乘火车/小汽车/公交 名词+介词 .Answer (key) to ... .......的答案（钥匙）Note to.... .....注释 Visit to 对.........访问 Love for... 对.........的热爱Difficulty with .......的困难 Way to / The road to... 通向.........的道路question with ... / the question of............的问题Trouble with. ..........的麻烦 动词+介词 Worry about... 为.........而担忧 talk about 谈论 Speak about 谈论、谈到 Hear bout 听说 Laugh at 嘲笑 Shout at... 对.........吼叫 Look for 找 Ask for / Get request 要求得到 Hear from.. / Receive a letter from..收到.......来信Come from 来自 Listen to 听 Arrive at / in 到达Help oneself to 随便吃、随便用Think about考虑、认为Have a look /look at 看一看 Smile at... 对.........微笑Knock at the ...... 敲 Take care of /care for 照料 wait for等待 Learn from..... 向.........学习die from 死于 Arrive / get to 到达Write... To... 给.........写信Say hello to...... 向.........问好
常用介词练习 ( )1.___ the afternoon of May, we visited the old man. A. On B. At C. In ( )2.Many people work ___ the day and sleep ___ night. A. on ; at B. in ; in C. in ; at ( )3.He speaks Japanese best ____ the boy students. A. between B. with C. among ( )4.A wolf ___ a sheep skin is our dangerous enemy. A. with B. in C. on ( )5.Joan hopes to come back ___ three days. A. after B. for C. in ( )6.They sent the letter to me ___ mistake. A. by B. for C. with ( )7.He left home ___ a cold winter evening. A. at B. on C. in ( )8.Shanghai is ____ the east of China. A. in B. on C. to ( )9.____ my father’s help, I hav e finished my composition. A. Under B. On C. with ( )10.He’s very strict ____ himself and he’s very strict ___ his work. A. with ; in B. in ; with C. with ; with
小学常用介词的基本 用法 -CAL-FENGHAI-(2020YEAR-YICAI)_JINGBIAN
常用介词的基本用法 1、at ①表示时间： I go to school at seven every day 我每天早上7点去上学。 ②表示在某一具体地点： He is standing at the bus stop 他站在公共汽车站。 ③表示动作的方向、目标： Let me have a look at the picture 让我看看这幅图。 ④用于某些固定搭配： at once 立刻、马上 at last 最后 at the same time 同时 at first 开始时 not at all 一点也不 2、about ①表示大约时间： I's about six o'clock now. 现在大约6点钟了。 ②表示地点；在……周围： Everthing about me is so beautiful 我周围的一切都那么美好 ③关于，对于： We are talking about the news. 我们正在谈论新闻。 3、after ①在……之后： After dinner I watch TV. 晚饭后我看电视。 ②在……后面： He came into the room after me. 他在我后面进了房间。 4、behind ①在……之后： There is a bike behind the tree. 树后有一辆自行车 ②比……晚，迟于： The train is behind time. 火车晚点了 5、by ①在……旁： He is sitting by the bed. 他正坐在床边。 ②到……时候： We have learned three English songs by now. 到现在为止，我们已经学会了三首英文歌曲。 ③以……方式： I go to school by bus. 我乘公共汽车去上学。 ④用于某些固定搭配： one by one 一个接一个 by the way 顺便说一句 6、for ①为，给，替： I'll make a card for my teacher. 我要给老师做张卡片。 ②由于： Thank you for helping me. 谢谢你帮我。 ③表示给（某人）用的： There is letter for you. 这儿有你一封信。 7、in ①在……里面： The pencil is in the desk. 铅笔在课桌里。 ②在一段时间里： We have four classes in the morning. 我们上午有四节课。 ③用，以： What's this in English 这用英语怎么说 ④在某一年份，季节，月份： in 2002, in spring, in January ⑤表示状态，服饰： Helen is in yellow. 海伦身穿黄色衣服。 ⑥在……方面： He is weak in English. 他的英语不行。 ⑦用于某些固定搭配： in front of 在……前面 in the end 最后 in time 及时 8、like ①像……样： He looks like his father. 他像他的父亲。 ②这样，那样： Don't look at me like that. 别那样看着我。
小学常见介词和介词短语 一、含义: 介词是表示两词之间的关系的词。我们在小学学过的英语介词有： 1. on (1) 在------上面The book is on the desk. (2) 在------（哪一天/星期）What do you do on Wednesday? (3) 在------（月、日）My birthday is on August 2nd. 2. in （1）在------里面The pens are in the pencil-box. ( 2 )在------（哪一年/月）His birthday is in October. He worked here in 1992. (3 ) 在------（地方）He works in Dongguan. (4 ) 在------之内What are you going to do in 20 years? (5 ) 在------（早上、下午、晚上）I do morning exercises in the morning every day. I usually play basketball in the afternoon. I often do my homework in the evening. 3. under 在------底下There is a ball under the bed. 4. near 在------附近There is a book shop near our school. 5. in front of 在------前面A boy is standing in front of the house. 6. beside 在------旁边A football is beside thedoor. 7. next to 紧挨着There is a bus station next to No. 13 Middle School. 8. over 在------正上方A bridge is over the river. 9. on the left 在------左边The bookstore is on the left. 10. on the right 在------右边The hospital is on the right. 11. before 在……之前Mike sits before me. 12. after 在------以后He went home after school. 13. in the middle 在------中间The road is in the middle. 14. at (1 ) 在------（小地方）I am at school today. I was at home yesterday. (2 ) 在------（点钟）I usually go to school at 8:00 am. （3）看一看Look at the blackboard. (4) 在中午at noon 15. behind 在------后面There is a broom behind the door. 16．For (1) 给This present is for you. (2) 为了Thank you for telling me the way to the zoo. (3) 作为We have some chips and hamburgers for lunch. 17．To (1) 到Take your sportshoes to the P.E class. (2) 致Happy birthday to you. Give it to your friend. 18. from 来自I am from China. = I come from China. 19. from --- to 从------到------ Line up from shorter to taller. We have class from Monday to Friday. 20. of ------的He is a student of Kama School. 21. by （1）在------之前We must be at home by 6 o’clock. （2）乘------交通工具People can go to the moon by spaceship. I go to school by bus.
小学常见介词用法辨析 一、介词的定义及分类 介词是一种用来表示词与词、词与句之间的关系的虚词,，在句中不能单独作句子成分。介词后面一般有名词、代词或相当于名词的其他词类，短语或从句作它的宾语。按构成分为简单介词（in、on、at等）、合成介词（into、within等）、重叠介词（at about等）、短语介词（in front of等）。 二、小学常用介词用法释义 （一）表时间 1、常用词in、on、at。 In： ①+年份/世纪。in 2019（在2019年）；In the1990s（在19世纪90年代）. ①+月份。In May（在五月）. ①+季节。In spring/summer/autumn/winter（在春/夏/秋/冬季）. ①+一天的某个时间段（上午、下午、晚上等）。In the morning/afternoon/evening at ： ①+时刻、几点。at six（在6点）/~half past ten（在10点半） ①+年龄。at thirteen/~the age of thirteen（在13岁时） ①+某个时段at noon（在中午）,at night（在晚上）, at midnight（在午夜），at dawn（在黎明） on ： ①+星期几。on Wednesday/Sunday（在星期三/在星期日）
①+日期。On June 4th =on the fourth of June （在六月4日） ①+有day的节日。On Christmas Day/Teacher’s Day（在圣诞节/教师节）①+具体某一天。On a cold day（在一个寒冷的一天）、on Sunday afternoon（在星期日下午） 2、其他常用词 Before：在...之前after：在...之后since：自从...开始for +一段时间until：直到...时候from...to：从...到...（二）表方位 1、常用词in、on、at。 In： ①在...里面：In the classroom（在教室里） ①+大地点：In China（在中国）；in Nanjing（在南京） On： ①在上面（表面）：On the desk（在桌子上） ①在左右边：On your right（在你右边） At： ①+小地点（大、小是相对而言）：at home（在家）；at the party（在宴会上）。 ①向，朝向：laugh at/shout at/point at 2、其他常见方位词