The reason why the precision injection molding machine must be high pressure is:

1) 提高精密制品的精度和质量，注射压力对制品成型收缩率有最明显的影响。当注射压力达到392MPa时，制品成型收缩率几乎为零。而这时制品的精度只受模具控制或环境的影响。实验证明：注射压力从98MPa提高到392MPa后，机械强度提高3%～33%。    

1) improve the precision and quality of precision products, and injection pressure has the most obvious effect on product shrinkage. When the injection pressure reaches 392MPa, the shrinkage rate of the product is almost zero. At this time, the accuracy of products is only affected by mold control or environment. The experiment proved that the mechanical strength increased by 3% to 33% after the injection pressure increased from 98MPa to 392MPa. Such

    

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2) 可减小精密制品的壁厚、提高成型长度。以PC为例，普通机注射压力177MPa，可成型0.2～0.8mm壁厚的制品，而精密机注射压力在392MPa时可成型厚度在0.15～0.6mm 之间的制品。超高压注射机可获得流长比更大的制品。    

2) it can reduce the wall thickness and improve the molding length of precision products. Taking PC as an example, the injection pressure of 177MPa can be used to form products with 0.2 ~ 0.8mm wall thickness, and the injection pressure of precision machine can be molded between 0.15 and 0.6mm when the injection pressure is 392MPa. The ultra-high pressure injection machine can obtain products with larger flow length ratio. Such

3) 提高注射压力可充分发浑注射速率的功效。欲达到额定注射速率，只有两个办法：一是提高系统最高注射压力；二是改造螺杆参数，提高长径比。精密注射机的注射速率要求高。以德国制造的DEMAG精密注塑机(60～420吨)为例，它的注射速度能达到1000mm/s，螺杆能获得12m/s2的加速度。

3) increasing the injection pressure can give full play to the effect of injection rate. To achieve the rated injection rate, there are only two ways: first, to increase the maximum injection pressure of the system; the two is to improve the screw parameters and increase the ratio of length to diameter. The injection rate of the precision injection machine is high. Take the German DEMAG precision injection molding machine (60~420 tons) as an example, its injection speed can reach 1000mm/s, and the screw can get the acceleration of 12m/s2.