Dragon Boat Festival just finished, and today to the Children's Day, and you Dongguan Plastic mold factory big friends, you should not rub the festive of the festival it But the editor to tell you, from the next holiday holiday is the National Day, there is a good distance. Today for everyone to introduce plastic mold injection molding process parameters pressure.
Plastic pressure (back pressure): refers to the use of screw-type injection machine, the top of the screw melt in the screw rotation back when the pressure.
The plasticizing pressure increases, the melt temperature and its uniformity are improved, the colorant is mixed uniformly and the gas in the melt is discharged. But the plasticization rate is reduced to extend the molding cycle.
In general operation, in ensuring the quality of plastic under the premise of plasticization pressure should be as low as possible, generally about 6MPa, usually rarely more than 20MPa.
The pressure applied to the plastic melt at the top of the plunger or screw.
Role: injection to overcome the melt flow filling process in the flow resistance, so that the melt has a certain filling rate; packing pressure when the melt and to prevent backflow.
Size: depending on the type of injection machine, plastic variety, mold structure, mold temperature, plastic wall thickness and the structure and size of the casting system.
Under normal circumstances:
High viscosity plastic injection pressure> low viscosity plastic;
Thin wall, large area, the shape of complex plastic injection pressure is high;
Mold structure is simple, gate size larger, lower injection pressure;
Plunger injection machine injection pressure> screw injection machine;
Barrel temperature, mold temperature is high, the injection pressure is low.
Note: The above information from the Jiezheng mold on the Internet, welcome reproduced, indicate the source!