Plastic Fruit Bowl Injection Mould

Performance of plastic injection mold materials

Many plastic products we see in our life need molds for manufacturing. Plastic molds have some performance requirements for mold materials in order to adapt to various mold working conditions. What performance requirements should plastic injection mold materials have?

1. High-temperature performance

When the working temperature of the mold is higher, hardness and strength are lowered, resulting in early wear or plastic deformation of mold and failure. Because mold material should have high anti-tempering stability to ensure that mold has high hardness and strength at working temperature.

2. Resistance to hot and cold fatigue

Some molds are in a state of repeated heating and cooling during the working process, causing the surface of the cavity to be subjected to tensile and pressure-induced stresses, causing surface cracking and spalling, increasing friction, impeding plastic deformation, and reducing dimensional accuracy, thereby resulting in mold failed. Hot and cold fatigue is one of the main forms of hot work die failure. It should have high resistance to cold and heat fatigue.

3. Corrosion resistance

Some molds, such as plastic molds, when plastic mold is working, due to the presence of chlorine, fluorine, and other elements in plastic, after heat is resolved to analyze strong corrosive gas, eroding the surface of the mold cavity, increase its surface roughness, and aggravate the wear and tear.

4. Wear resistance

When blank is plastically denatured in the mold cavity, it flows and slides along the cavity surface, causing severe friction between the surface of the cavity and the blank, which causes mold to fail due to wear. Therefore, the wear resistance of the material is one of the most basic and important properties of mold. Hardness is a major factor affecting wear resistance. In general, the higher hardness of the mold part, the smaller the wear amount, and the better the wear resistance. In addition, wear resistance is also related to the type, quantity, shape, size, and distribution of carbides in the material.

5. Strong toughness

Most of the working conditions of mold are very bad, and some often suffer from a large impact load, resulting in brittle fracture. In order to prevent mold parts from suddenly breaking during work, the mold must have high strength and toughness. The toughness of mold depends mainly on carbon content, grain size, and the microstructure of the material.

During the working process of mold, under the long-term effect of cyclic stress, fatigue fracture is often caused. Its’ form has small energy multiple impact fatigue fracture, tensile fatigue fracture contact fatigue fracture, and bending fatigue fracture. Fatigue fracture properties of a mold depend mainly on its strength, toughness, hardness, and amount of inclusions in the material.