(1) Number and arrangement of cavities. When the plastic part is designed and selected, it is necessary to consider whether to use a single cavity mold or a multi-cavity mold. The number of cavities should be determined: 1 Batch and lead time of plastic parts. 2 Plastic mold quality control requirements. 3 Shapes and dimensions of molded plastics and plastic parts. 4 The cost of plastic parts. 5 cavity layout.
(2) Selection of parting surface. The parting surface should be selected at the maximum contour of the plastic part; determine the favorable retention mode to facilitate the smooth release of the plastic parts; ensure the precision requirements of the parts; meet the appearance requirements of the plastic parts; facilitate the processing and manufacturing of the mold; Effect; favorable for lateral core pulling.
The design of the gating system and the drainage system is generally composed of four parts: the main channel, the runner, the gate and the cold hole. Whether the design of the pouring system is reasonable not only has great influence on the performance, structure, size, internal and external quality of the plastic parts, but also related to the utilization rate of the plastic used for the plastic parts and the molding production efficiency. The overflow system mainly excludes the low-molecular volatile gas generated by the air or plastic in the cavity heated or solidified. There are usually four ways: 1 Use the clearance gap to exhaust. 2 Open the exhaust vent on the parting surface. 3 Exhaust with the vent plug. 4 Mandatory exhaust.