Molding process pressure: Pre-plastic back pressure: injection pressure, mold clamping pressure, pressure holding, mold and neutron pressure, shooting table pressure, etc.
Pre-plastic back pressure: high back pressure and high storage density, and a large amount of storage in an equal storage volume. Low back pressure, low storage density and low storage. After setting the storage position, and then making a large adjustment of the back pressure, you must pay attention to reset the storage position, otherwise it will easily cause the product to fluff or insufficient.
Injection pressure: different varieties of plastics have different melt viscosities, and amorphous plastics have a large viscosity change with plasticizing temperature. Injection pressure is set based on the weld viscosity of the plastic and the plastic flow ratio. If the injection pressure is set too low, the product is undershot, dents, weld lines and dimensional instability. The injection pressure is too high, and the product is flashed, and the discoloration and sticking are difficult to eject.
Clamping pressure: depending on the projected area of the mold cavity and the injection pressure. The mold clamping pressure is insufficient, and the product is easy to fly and the weight is increased. If the clamping force is too large, it is difficult to open the mold. Generally, the clamping pressure is set to not exceed 120 par/cm2.
Holding pressure: When the injection is over, continue to give the screw a pressure to hold the pressure. At this time, the product in the mold cavity has not been frozen. The pressure can continue to refill the mold cavity to ensure that the product is full. The pressure holding and pressure setting are too high, which brings great resistance to the mold and the ferrule. The product is easy to be white and the top is warped. In addition, the mold runner gate is easily filled with plastic, and the gate is broken in the flow channel. Under-pressure products have dents and dimensional instability.
The mold and neutron pressure, set the mold and neutron pressure principle is to set the pressure according to the size of the mold cavity area and the core projection area of the ferrule, and the geometric complexity of the molded product. size. Generally, the pressure of the mold and the neutron cylinder should be set to push the product.
