诚信橡胶注射机厂

精密注射机在控制方面的特点

Characteristics of precision injection molding machine in control

    

    

1) 对注塑成型参数的重复精度(再现性)要求高，宜采用多级注射反馈控制：

1) high accuracy (reproducibility) requirement for injection molding parameters. Multi stage injection feedback control should be adopted.

a.多级位置控制；

A. multilevel position control;

b.多级速度控制；

B. multilevel speed control;

c.多级保压控制；

C. multi stage pressure keeping control;

d.多级背压控制；

D. multi stage backpressure control;

e.多级螺杆转速控制。

E. multistage screw speed control.

位移传感器的精度要求达到0.1mm，这样可以严格控制计量行程、注射行程以及余料垫的厚度(射出监控点)，保证每次注射量准确，提高制品成型精度。料筒及喷嘴温度控制要精确，升温时超调量要小，温度的波动要小。精密注塑应采用PID控制，使温度精确度在±0.5℃之间为宜。    

The precision of displacement sensor should reach 0.1mm, which can strictly control the measuring stroke, injection stroke and the thickness of residual material pad (injection monitoring point), ensure the accuracy of each injection and improve the molding accuracy of the products. The temperature control of the barrel and nozzle should be precise. When the temperature rises, the overshoot is small and the temperature fluctuation is small. Precision injection molding should be controlled by PID, so that the accuracy of temperature should be between 0.5 and C.    

2) 塑化质量要求，塑料塑化的均匀性不仅影响到注塑件的成型质量，还会影响到熔融塑料通过浇口时所受阻力的大小，为了得到均匀的塑化，设计专用的螺杆和使用专用的增塑技术必不可少。另外，机筒的温度也应精确控制，现在螺杆、机筒温度多采用PID控制(比例、微分、积分)，精度可控制在±l℃内，基本可满足精密注塑的要求，如果采用FUZZY控制方法，就更适合于精密注塑了。

2) Plasticization quality requirements, plasticization uniformity not only affects the quality of injection molding parts, but also affects the resistance of molten plastics through the gate size, in order to get uniform plasticization, the design of dedicated screw and the use of dedicated plasticization technology is essential. In addition, the barrel temperature should also be precisely controlled. Now the screw and barrel temperature are mostly controlled by PID (proportional, differential and integral). The precision can be controlled within L, which can basically meet the requirements of precision injection molding. If the FUZZY control method is adopted, it is more suitable for precision injection molding.

3) 工作油的温度控制要高油温的变化导致注射压力的波动，必须对工作油采用加热、冷却的闭环装置，把油温稳定在50～55℃为宜。    

3) In order to control the temperature of working oil and cause the fluctuation of injection pressure due to the change of high oil temperature, it is necessary to adopt a closed-loop heating and cooling device for working oil, so that the oil temperature should be stabilized at 50-55 C.    

4) 保压压力的影响，保压对精度塑件的影响极大，准确地说，保压能较好地补缩，减小塑件变形，控制塑件精度，保压压力的稳定决定了塑件的成型精度，螺杆的终止位置不变是决定保压效果的决定因素。    

4) The influence of packing pressure and the influence of packing pressure on precision plastic parts are very great. To be exact, the packing pressure can feed well, reduce the deformation of plastic parts, control the precision of plastic parts, and the stability of packing pressure determines the molding precision of plastic parts. The constant termination position of screw is the decisive factor to determine the packing effect.    

5) 对模具温度控制要求若冷却时间相同，模具型腔温度低的制品厚度要比温度高的制品厚度尺寸大。如POM、PA类材料，模温50℃时厚度为50～100μm的制品，在80℃时厚度减小到20～40μm，100℃时减小到只有10μm。室温也对精密制品尺寸公差有影响。

5) If the cooling time is the same, the thickness of the product with low cavity temperature is bigger than that with high temperature. For example, POM and PA materials, the thickness of the products with 50-100 micron thickness at mold temperature of 50 C, 20-40 micron thickness at 80 C, and 10 micron thickness at 100 C. Room temperature also affects the dimensional tolerances of precision products.