What are the characteristics of plastic mold ABS injection molding process


ABS, commonly known as acrylonitrile butadiene styrene, […]

ABS, commonly known as acrylonitrile butadiene styrene, is made by copolymerizing three monomers of acrylonitrile-butadiene-styrene. Due to the different ratios of the three monomers, they can have different properties and melting temperatures. If ABS with fluidity is blended with other plastics or additives, it can be expanded to ABS with different uses and properties, such as impact resistance and heat resistance. , Flame retardant, transparent, reinforced, electroplating, etc.
The fluidity of ABS is between PS and PC, and its fluidity is related to injection temperature and pressure. The influence of injection pressure is slightly greater. Therefore, higher injection pressure is often used in molding to reduce melt viscosity and increase mold filling. performance.
1. Plastic processing
The water absorption rate of ABS is about 0.2%-0.8%. For general grade ABS, use an oven to bake at 80-85°C for 2-4 hours or use a drying hopper at 80°C for 1-2 hours before processing. For heat-resistant ABS containing PC components, the drying temperature should be appropriately increased to 100°C, and the specific drying time can be determined by air extrusion. The use ratio of recycled materials cannot exceed 30%, and electroplating grade ABS cannot use recycled materials.

2. Injection speed
Use slow speed for fireproof grade and fast speed for heat resistant grade. If the surface requirements of the product are high, high-speed and multi-stage injection rate control should be used.
3. Post-processing of products
Generally, ABS products do not need post-treatment, only electroplating products need to be baked (70-80℃, 2-4 hours) to passivate the surface traces, and the products that need electroplating cannot use mold release agents, and the products should be packaged immediately after being taken out. .
4. Retention time
At a temperature of 265°C, the retention time of ABS in the melt cylinder cannot exceed 5-6 minutes at most. The flame-retardant time is shorter. If the machine needs to be shut down, the set temperature should be lowered to 100℃ first, and then the general-purpose ABS should be used to clean the plastic melt cylinder. The cleaned mixture should be put into cold water to prevent further decomposition. If you need to change from other plastics to ABS, you must first use PS, PMMA or PE to clean the melt cylinder. Some ABS products have no problems when they are just demolded, and they will only change color after a period of time. This may be caused by overheating or the plastic staying in the melt cylinder for too long.