What is the injection molding machine back pressure, back pressure role is what?
The formation of the plastic melting and plasticizing process in the plastic processing of back pressure, melt moving to the front end of the barrel (measurement and indoor), more and more, and gradually formed a pressure driven screw back. In order to prevent the screw from retreating too fast and to ensure uniform compaction of the melt, it is necessary to provide an opposite direction of pressure to the screw, which is the reverse pressure that prevents the screw from retreating.Back pressure is also known as plasticizing pressure, and its control is achieved by adjusting the oil return valve of the injection cylinder. Pre injection plasticizing screw injection molding machine is equipped with the rear end of the oil cylinder back pressure valve, regulating screw back when the injection cylinder oil cylinder speed, to maintain a certain pressure, shift speed screw motor after (resistance) is composed of AC servo valve control.
Adjustment of back pressureThe adjustment of the injection back pressure shall be determined according to the raw material performance, drying conditions, product structure and quality, and the back pressure should be adjusted at 3-15kg/cm 3. When the surface of the product has little Qihua, mixed color, shrink and product size and weight changes, may be appropriate to increase the back pressure. When the nozzle leakage glue, salivation, Melt Overheating product decomposition, discoloration and feeding back too slow may be considered appropriate to reduce the back pressure.Back pressure is one of the important parameters to control melt quality and product quality in injection molding process. Proper back pressure plays an important role in improving product quality, and can not be ignored!
When the screw is in the process of feeding, as the amount of material inside the barrel increases, forcing the screw back, and the control of its back speed is called back pressure, back pressure can increase the density of plastics, melting better
