Operating conditions for injection molding of rubber and plastic molds
1. Off mold pressure: In principle, it should be greater than the total pressure of the plastic injection mold, based on no flash.
2. Pressure and speed have some of the same contact effects in the mold. It is intended to make the material into the mold evenly, completely, and properly filled in all corners. Too low will result in short shots, shrinkage, too high hair, oversaturation, sticking, charring, vulnerable molds and high internal stress.
3. Speed: The speed of the resolution material in the mold runner and the product in the condition, there are flashing, full, burning, slow, short shot, shrinking, poor combination and easy to break.
4. Temperature: The materials are different, the temperature is different, the color of the solution is too low, and the internal stress of the product increases. If the temperature is too low, the supercharging is too high, which may cause the screw to crack, which is too high, the product has burrs, and the temperature difference due to cooling causes shortening. The material will differentiate, turn yellow, discolor, and easily crack. The cooling time becomes longer, the gas is not easily discharged, and there is gas.
5. Back pressure: The resistance of the screw to retreat when rotating the feed is called back pressure. The effect is to make the material tighter in the conveying contraction. The air and moisture of the material can be discharged from the screw. The sol contains no gas components that affect the appearance of the article. There will be bubbles at low, and the appearance is silver. High will overheat, agglomerate, overflow, long cycle, the screw does not retreat. The use of loosening together is very important: when the back pressure is low, some materials need to be retracted, while others do not need to be adjusted according to various materials. When the back pressure is high, it is necessary to use the principle of retracting and paying attention to whether the air is not involved or not.
6. The temperature of the mold temperature and the length of the cooling time, affecting the product's sticking, shrinkage, dimensional tolerance, appearance brightness, cycle, etc., should be adjusted according to the actual situation. Another acrylic, PC, if the product is thick, there must be mold temperature, so that bubbles and stress will not occur.
Article from: Deyibao Hardware Rubber Factory /