First, in the selection of materials to consider:
1. Physical and mechanical properties of plastics such as strength, rigidity, toughness, elasticity, water absorption and sensitivity to stress;
2, plastic molding process, such as fluidity, crystallization rate, sensitivity to molding temperature, pressure, etc.;
3. The shrinkage of plastic products after molding and the difference in shrinkage ratios.
Second, in the shape of the product: can meet the requirements of use, is conducive to filling, exhausting, feeding, and can be adapted to high-efficiency cooling hardening (thermoplastic products) or rapid heat curing (thermosetting plastic products).
Third, in the mold: should consider its overall structure, especially the complexity of the core and the product. At the same time, the shape of the mold part and its manufacturing process should be fully considered in order to make the product more economical.
Fourth, in terms of cost: we must consider the profit rate, annual output, raw material price, service life and replacement period of injection products, and reduce costs as much as possible.