1) The impact of shrinkage rate of raw materials The larger the shrinkage rate of the raw material, the lower the accuracy of the product. After strengthening or inorganic filling modification of plastic materials, their shrinkage rate will be greatly reduced by 1-4 times. The shrinkage processing conditions of plastics (cooling rate, injection pressure, processing method, etc.) are related to factors such as product design and Mold design. The order of molding accuracy from large to small for different molding methods: Injection Molding>extrusion>injection blow molding>extrusion blow molding>compression molding>rolling molding>vacuum suction molding 
2) The effect of raw material creep (creep refers to the deformation of the product under stress). General: Plastic materials with good creep resistance include PPO, ABS, PC, and reinforced or filled modified plastics. After strengthening or inorganic filling modification of plastic materials, their creep resistance will be greatly improved.
3) The effect of linear expansion of raw materials: linear expansion coefficient (thermal expansion coefficient) 4) The impact of raw material water absorption: After water absorption, the volume expands, leading to an increase in size and seriously affecting the dimensional accuracy of the product. The water absorption of raw materials can also seriously affect the physical and mechanical properties of the processed parts Plastics with high water absorption capacity, such as PA, PES, PVA, PC, POM, ABS, AS, PET, PMMA, PS, MPPO, PEAK, should pay attention to the storage and packaging conditions of these plastics. 5) Attention to the impact of raw material swelling!! The solvent resistance of raw materials can seriously affect the dimensional accuracy and physical and mechanical properties of products. For plastic products in contact with chemical media, plastic materials that cannot cause swelling should be selected. 6) Filler effect: After strengthening or inorganic filling modification of plastic materials, the dimensional accuracy of plastic products can be improved.
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