Sufficient surface hardness and wear resistance: the hardness of the plastic mold is usually below 50~60 HRC, and the heat-treated mold should have enough surface hardness to ensure that the mold has enough stiffness. In the work of the mold, due to the filling and flow of plastics, it is required to maintain the stability of the shape accuracy and dimensional accuracy of the mold, and ensure that the mold has enough service life. The wear resistance of the die depends on the chemical composition of the steel and the hardness of the heat treatment, so increasing the hardness of the die is conducive to improving its wear resistance.

Different plastic materials have different physical and chemical properties, such as strength, heat resistance, chemical resistance and so on. Therefore, when choosing materials, it is necessary to decide according to the needs of the product. For example, if the product needs high temperature resistance, it should choose high temperature resistant plastics; If the product requires high strength, high strength plastics should be selected.

Fluidity is a measure of the ability of plastic materials to flow and fill molds during injection molding. Materials with good fluidity are easier to injection, but may also require higher injection pressures. Therefore, when selecting materials, it is necessary to balance the fluidity of the material with the mold design and equipment capabilities

Cost is an important factor when choosing materials. The price of different plastic materials varies greatly, so it is necessary to choose the right material according to the cost budget of the product

In some cases, it may be necessary to use two or more different plastic materials to make a product. In this case, it is necessary to ensure that the selected materials are compatible with each other and that no chemical reactions or undesirable physical interactions occur

With increasing consumer concern for environmental protection, the choice of sustainable and environmentally friendly plastic materials has also become an important consideration. For example, using recycled or bio-based plastics can reduce the impact on the environment

To sum up, choosing the right material for injection molding is a multi-faceted decision-making process that takes into account the performance needs of the product, the fluidity of the material, the cost, compatibility and sustainability.