The characteristics of the precision injection machine in control

    

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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. multistage speed control;

c.多级保压控制；

C. multistage pressure protection control;

d.多级背压控制；

D. multistage back pressure 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 the displacement sensor is required to reach 0.1mm, which can strictly control the metering stroke, the injection stroke and the thickness of the residual cushion (shooting out the monitoring point), so as to ensure the accuracy of each injection and improve the molding precision 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. Such

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) the quality of plasticizing is required. The uniformity of plastic plasticization not only affects the molding quality of the plastic parts, but also affects the resistance of the molten plastic through the gate. In order to get the uniform plasticization, the design of special screw and the use of special plasticizing technology is essential. In addition, the temperature of the cylinder should be controlled accurately. Now the temperature of the screw and barrel is mostly controlled by PID (proportion, differential and integral). The precision can be controlled within + L C, and it can basically meet the requirements of precision injection molding. If 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) the temperature of the working oil is controlled by the change of the high oil temperature, which leads to the fluctuation of the injection pressure. It is necessary to use the closed loop device of heating and cooling the working oil, which is suitable to stabilize the oil temperature at 50~55. Such

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 pressure retaining pressure on the precision plastic parts is greatly influenced by the pressure protection. To be accurate, the pressure retention can be well compensated, the deformation of the plastic parts is reduced, the precision of the plastic parts is controlled, the stability of the pressure holding pressure determines the molding precision of the plastic parts, and the constant position of the screw is the decisive factor to determine the effect of the pressure protection. Such

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) for mould temperature control, if the cooling time is the same, the thickness of products with low mold cavity temperature is larger than that of products with high temperature. For example, POM, PA materials, when the mold temperature is 50 degrees, the thickness of the product is 50~100 micron m, the thickness decreases to 20~40 m at 80 degrees, and decreases to 100 m at 10 degrees. Room temperature also affects the dimensional tolerance of precision products.