six conditions of plastic injection molding

- Mar 15, 2018-

         In order to make plastic molds appear damaged or abnormal after injection molding, we need to carry out certain specifications and conditions for mold injection molding. Its main requirements meet the following six conditions: 

         1. Closing mold pressure: In principle, it should be greater than the total pressure injected into the mold by the plastic, so that no burrs are used as a benchmark.                                                               

          2, pressure and speed have the same part of the role in the mold. The purpose of the raw materials into the mold can be uniform, thorough, adequate amount of full of all corners. Too short to shoot, shrink, too high hair, overfull, sticky Die, burnt, vulnerable molds and high internal stress.                     

           3, speed: the speed of the decision on the speed of raw materials in the mold runners and finished products in the state, there are fast edges, oversaturated, charred, slow short shot, shrink, combined with easy to break and so on. 

            4, temperature: different raw materials, different temperatures, too low color of the solution adhesive, the internal stress of the finished product is increased. Because the temperature is too low and the pressure is too high, it may cause the screw to break, is too high, the product has flash, and because of the cooling The temperature difference causes shrinkage. The raw material will decompose, turn yellow, change color and break easily. The cooling time becomes longer, the gas is not easily discharged, and there is gas.

           5. Back pressure: The resistance that the screw retreats when it rotates and feeds is called back pressure. Its role is to make the raw material more compact in conveying and compressing. It can make the air and water of the raw material discharge from the screw. It will not affect the surface of the finished product in the sol. The gas composition. There will be low air bubbles, surface silver lines. High overheating, agglomeration, plastic overflow, long cycle, the screw does not retreat. At the same time, the application of loose retraction is very important: when the back pressure is low, some raw materials must be retreated. It is not necessary to adjust the back pressure according to the raw materials of various natures. When the back pressure is high, it is necessary to use a loose and pay attention to the distance from the air or the glue.            6, the level of mold temperature and cooling time, affecting the finished mold, shrink, dimensional tolerances, surface brightness, cycle, etc., should be adjusted according to the actual situation in due course. Another acrylic, PC, such as finished meat when thick Mold temperature will not produce bubbles and stress.