1.The temperature of injection molding machine barrel controlled by the microcomputer, select the appropriate algorithm to control the heating band outside the barrel of the injection machine. Ensure that the working temperature of each section of the barrel can be kept within the set range according to the technical requirements. For precise plastic injection molding, accurate temperature control is beneficial to improve the quality of the product and the utilization rate of raw materials. It is a very important indicator.
3.The injection molding machine producing different products, the pre-plasticization is different, the ambient temperature is different, and the parameters of the barrel temperature are different when the production cycle is different. There is a strong coupling phenomenon between the temperature control of each section, to achieve complete decoupling control is very difficult. In addition, the object is still a large lag system, and conventional control methods will inevitably have large overshoot and oscillating phenomena. Therefore, it is necessary to study adaptive temperature control strategies to achieve high-precision temperature control.
5.The nozzle temperature directly affects the shear flow when the melt passes, which has a great influence on the quality of the product, so the control accuracy requirement of the nozzle temperature is higher. Mold temperature refers to the temperature of the cavity surface that touches with the product, which can significantly affect the filling, cooling, and holding pressure process.
2.The temperature control of injection molding machine barrel is a nonlinear, uncertain, strong coupling and large lag system, which is one of the control difficulties. For such objects, there is currently no uniform and effective control method, and the conventional PID control method cannot meet the requirements of high precision injection.
4.In plastic processing, temperature control mainly includes temperature control of the barrel, nozzle and mold. The barrel temperature is the heating temperature of the barrel surface. Because the wall of the barrel is relatively thick, the selection of the thermocouple detection point is very critical, and the temperature curves at different detection points are quite different. Therefore, the two-point parallel detection, that is, the simultaneous setting of the thermocouple on the surface and the depth of the cylinder, will obtain a relatively stable temperature curve, which is favorable for the accuracy of temperature control.