【正文】 measurement of the relative screw length and the overall length of screw smaller, in the plastics materials unit at the time also bee shorter. Screw thread is similar to widening the materials can be avoided stay longer so that the screw and stable operation. Lo deep groove width than correspondingly smaller, which create a lot of engineering plastics parts of the small diameter screw particularly effective. Melt homogeneity and are not small pression ratio decreases, it is because from the very shallow groove Lo caused very strong result of the shear rate. Feeding the difficulty of the design, it must ensure that all aggregates can be fed into evenly. Considering the need to shorter cycles, plastics rate must also be big enough, in the design of the feed must be effectively resolved the contradiction between. In addition, if adopted by a twostage injection screw to achieve precise control injection error, which requires the measurement of the melt through spherical valve detected by injection to injection molding machine in the Detroit injection molding machine.Before microprocessor controlled by the injection molding process can not be obtained through injection precision voltage parator has been successfully resolved. Voltage parator allows Transmitter and other sensitive came with the very precise voltage signal passed, and when the set point appears to be following the true value of a timely signal immediately transmitted to the microprocessor control of the order, by order of the cycle of operational procedures Asynchronous from time to time through a direct transfer of the signal process to eliminate, greatly improving the control accuracy. 4, precision molding technology in the mold injectionpression molding applications (ICM) technologyICM technology is the means to open a certain distance die under the conditions of the beginning injection, injection to a certain amount, the mold cavity beginning of the closure of the melt pression, injection mold pletely closed at the termination, and then packing, cooling until the removal products. Through injectionpression molding of pression products to paction, making products on the surface of uniform pressure distribution, the paction products such size high accuracy and stability, small deformation. It is in the mould open circumstances melt into the cavity and, therefore, mobile channel, for the low pressure injection molding, and reduce or eliminate the pressure caused by the resinmolecular orientation of the stress and products, which improve products, dimensional stability. ICM technology and flexible control capability than the injection mould has greatly improved. Therefore use of this technology can produce more precision parts, especially the highprecision cylindricalshaped parts. highspeed injection moldingHighspeed injection molding method of filling melts faster rate than the traditional 10 to 100 times, melt in the mold cavity to produce high shear flow, decrease viscosity, injection speed, slow down plastic surface hardening, thus improving thin Forming products wallthickness limit, inhibit excessive molding pressure, as well as because of the lowvoltage mobile mode, the products reduce stress. The thinwall precision products, we can use the injection screw at the forward from the melt energy absorption in the screw after the cessation of movement through the expansion of highspeed melt full cavity to achieve. nopressure injection moldingNopressure injection molding technology refers to the plastic melt highspeed, highpressure filling into the mold, and then close in the nozzle needle to melt the plastic mold cavity products automatically pensate for different parts of the contract, such products can be greatly reduced warpage. However, this method requires prior estimate packing contraction added, hence the need for the injection of a higher cavity pressure value, and we need clamping force also high. Other Intelligent Control TechnologyPrecision injection molding processing conditions in the process of continuous monitoring and implementation of precise control is very important. With the development of puter technology, puterized injection molding has been widely used. Among them, statistical process control (SPC), P ID technology, fuzzy logic control (FCC), network control center (NNC) method and the processing model based on the reverse of the backbone network size control. 5. ConclusionOn the highprecision plastic products, and highperformance requirements of the growing precision injection molding technology is the impetus for moving forward, people on the principle of precision injection molding, the constant deepening of understanding of precision injection molding technology is the basis for progress. With new materials, new processes and new equipment has emerged, particularly in the plastics processing puter is the wide application of the precision injection technology to create good conditions. As long as a reasonable use of these technologies, we will be able to produce sophisticated products.