When the surface raw materials at the wall thickness of Dalian injection molding are pulled in, there are concave marks on the surface of the finished product. Shrinkage is the most undesirable phenomenon on the surface of finished products, mostly at the wall thickness. Generally, if the pressure decreases, the shrinkage probability will be greater. The raw material of the part that is difficult to cool will move there.

Try to control shrinkage in a place that does not affect the quality of finished products. General injection molding machines can be operated manually, semi-automatic and fully automatic. Manual operation is in a production cycle, each action is realized by the operator turning the operation switch. Generally, it is only selected when commissioning and mold adjustment.

During semi-automatic operation, the machine can automatically complete the action of a work cycle. During normal production, semi-automatic or full-automatic operation is generally selected. At the beginning of operation, the operation mode (manual, semi-automatic or full-automatic) shall be selected according to the production needs, and the manual, semi-automatic or full-automatic switches shall be toggled accordingly.

The semi-automatic and full-automatic working procedures have been determined by the line itself, which also avoids the solidification of molten material in the nozzle hole. After the injection is completed and the cooling timer is timed, the pre molding action starts. The screw rotates to melt and squeeze the plastic in front of the screw head. When the screw retreats to a predetermined position (this position is determined by the travel switch to control the backward distance of the screw and realize quantitative feeding), the pre molding stops and the screw stops rotating.