1、 Precision injection molding technology of progress Author : Masaki Mikell Chen Chun Abstract : Introduction about precision injection molding technology of the polymer materials, and discussion about factors which impact the precision injection molding, including the precision of the mold， the cont
2、rol accuracy of the injection molding machine, the process control of precision injection and other computer control technology. Discussed to each of these factors, and given the relevant solutions, finally, introduce a number of advanced molding technology. Keywords : Precision Injection, Injection
3、 Machine， Precision Injection Mold In recent years, with the rapid development of the electronics, telecommunications, health care, automotive, and other industries， the demand to high-precision and high performance of plastic products is increasing day by day, prompted precision molding technology
4、continues to progress, new technologies continue to emerge. Precision injection molding products not only require high dimensional accuracy, low warpage， good to write, but also require excellent optical properties 1. Injection molding is the most important method of the plastic molding, including p
5、lastics plastics， injection, and packing, several basic cooling process, so there are many factors which can impact precision injection molding. 1 Precision Mold To create sophisticated products, precision mold is essential. Generally the accuracy of the Mold controlled by the mold temperature, the
6、precision manufacturing mold and the selection of plastic shrinkage rate when mold design . 1.1 The Control Precision of The Mold Temperature General precision parts in the injection molding, temperature control of mold is to increase productivity. However， the impact of temperature control of mold
7、for precision injection molding is great 2, it affects component of contraction, shape, crystallization, stress and so on, therefore mold design temperature loop temperature distribution at the request reasonable, control accuracy is precise. Wen preferred mode control and a cool-water machine. Mold
8、 temperature control and cooling time on product performance and the impact is as follows 3 : (1)Melt plastic injection and the cycle time of mold cavity can make fluctuations of the temperature difference ， therefore be to minimize the volatility worse peaks. (2)Heat transfer of mold is through the
9、 concrete and mold die within the media around the world. Mold is unchanged and therefore control of the media is the key, the general import and export of its cooling water temperature is less than 1 , application of the theory to the average temperature calculated 4, this can guarantee the stabili
10、ty of heat transfer. (3)Stable state of mold to maintain a balance between absorption and distribution of heat, injection molding machine should strictly maintain a stable temperature. 1.2 The Design And Manufacture of Precision Mold The premise to guarant precision component size of plastic is mold
11、 design in order to improve the precision of precision injection mold, using computer-aided analysis is necessary in the design process， especially on the gating system and the behavior of mold temperature control system heat distribution analysis. 1.3 The Use of Precision Mold Design Shrinkage Rate
12、 Precision injection molding machine generally has larger injection of power, make difficulties to mold design, size and cavity size precision control products 5. Precision plastic parts of the design prior to manufacture simple mold to measure the molding part of the actual shrinkage, this will gre
13、atly improve the accuracy of component size. 2 Best Precision Iinjection Molding Process Parameters Settings To the best molding process parameters to reduce plastic products, the shrinkage rate. Parts of the wall thickness difference is generally considered by the two factors :. （ 1） Melt hypertens
14、ion caused by mold cavity minor deformation； （ 2） When the mold cavity flexibility of the material after expansion. 3 Precision Injection Molding Machine Used to Replace Conventional Injection Molding Machine Precision injection molding machine generally larger injection of power, Besides meet injec
15、tion pressure and injection rate of requirements, Power will be injecting itself on the accuracy of a certain role in the improvement. 3.1 The consistency of molding cycle time General typical injection molding machine with three modes： manual, semi-automatic and fully automatic. Due to the influenc
16、e of various factors, in the former two models under each molding cycle time vary, this will affect the mold temperature and melt materials in the residence time, thereby affecting the precision of the parts made, so in Precision molding should maximize the use of fully automatic mode 14. 3.2 The Te
17、mperature Control of Precision Injection Molding Machine, And A New Design of Screw. Injection barrel automatic thermostat on the cycle of sexual relations and the opening of the stove to melt density and viscosity changes. Products thus affecting the quality and accuracy of the cyclical fluctuation
18、s； injection molding machine nozzle close to the mold cavity. Therefore, the nozzle temperature of molding component will have an important impact. 4 Precision Molding Technology 4.1 Application of The Mold Injection Compression Molding (ICM) Technology ICM Technology is the means to open a certain
19、distance from the mold under the conditions of the beginning injection, injection of a certain amount, close to the beginning die cavity melt implementation of the compression, Die completely closed at the termination of injection, and then packing, cooling until the removal products. 4.2 The High-s
20、peed Injection Molding High-speed injection molding method of filling melts faster than traditional fast 10 100 times, so that melt in a mold cavity to produce high shear flow and viscosity, mold filling fast, plastic surface hardening slowed, will be enhanced thin-wall molding thickness limit, inhi
21、bit excessive molding pressure and low-pressure die as mobile, products, the lower the stress. 4.3 No Guarantee Pressure Injection Molding Without packing injection molding technology is referred to the plastic melt in high-speed, high pressure filling into the mold, then close to the nozzle needle,
22、 a plastic mold cavity melt automatically cover all parts of the product contraction Such products can greatly reduce the warpage. 4.4 Other Intelligent Control Technology Precision injection molding process on the processing conditions for continued monitoring and accurate control is very important. With the development of computer technology, computerized injection molding has been widely used .
