With the application of plastic products in the automobile industry, automobile plastic mould has also been rapidly developed. Most of the materials used for automobile plastic moulds are engineering grade plastics. So, what are the engineering-grade plastics commonly used in automobile plastic moulds?
Glass fiber reinforced plastics
The glass fiber reinforced plastic is based on the original pure plastic, glass fiber and other additives and then added into to increase the using range of the material. In general, most of the glass fiber reinforced materials are usedin automobile structural parts, such as: PP, ABS, PA66, PA6, PC, POM.
Advantages of the glass fiber reinforced plastics:
1. It an extremely high-temperature resistant material after glass fiber is reinforced, which is much better than before without glass fiber, especially nylon plastic raw materials.
2. It restricts the mutual movement between the polymer chains of the plastic, resulting in a decrease in shrinkage and also a greatly improved product rigidity.
3. The glass fiber reinforced plastic will not be subjected to stress and cracking, it improves its impact resistance performance.
4. Glass fiber is a high-strength material, which improves the strength of plastic.
5. The combustion performance of reinforced plastics is greatly reduced due to the addition of glass fiber and other additives.
Disadvantages of glass fiber reinforced plastics:
1. It will change the opacity of plastic materials.
2. It reduces the toughness of the plastic and increases the brittleness of the product.
3. It makes the viscosity increase, the fluidity becomes worse, and the injection pressure must be increased.
4. It has poor liquidity. In order to have a normal injection, the injection temperature of all reinforced plastics should be increased by 10℃-30℃ compared with that without fiber glass.
5. It enhances the hygroscopicity of the plastic, and it must be dried during injection moulding.
6. In the injection moulding process, glass fiber can enter the surface of the plastic product, making the surface of products very rough.
7. Glass fiber is a material with high hardness. A very corrosive gas occurs after the additives are volatilized at high temperature, it has great wear and corrosion on the screw of the injection moulding machine and the plastic mould of the automobile. Therefore, it is necessary to pay attention to the surface anti-corrosion treatment and surface hardness treatment of the equipment when producing the automobile plastic mold and injection molding machine with typical materials.