H.D.Plastics is a premier ABS extrusion manufacturer and exporter with high standard quality with Color ABS Profile, Co-Extruded ABS Profile, ABS channels, and other shapes as well.
Here we will analyze several problems that may occur during the ABS extrusion process.
Now a series of heat-resistant ABS resins have been developed which can reach a heat distortion temperature (HDT) of 90-120°C. Because the molecular structure of heat-resistant ABS contains high-rigidity benzene ring and N-phenyl group, the heat resistance, as well as the steric hindrance effect of the molecular chain also increased. It results in the reduction of the relaxation speed of the molecular chain. But there is too much internal stress increased at the same time, which leads to defects such as stress cracking, stress whitening, and product brittleness of ABS profile products. Therefore, reducing the internal stress of the product is the key to the heat-resistant ABS extrusion process.
We should pay special attention to the ABS extrusion temperature during the heat-resistant ABS extruding process. Its setting mold is based on heat-resistant ABS is fully plasticized. The increase in extruding temperature will significantly reduce the viscosity of heat-resistant ABS but increase the fluidity of the resin. In this wya it will make the flow distance longer to ensure that the material has sufficient filling capacity.
Holding pressure and time range: For heat-resistant ABS profiles, whether the setting of holding pressure and time is reasonable or not directly affects the internal stress of the part. The increase of the holding pressure will reduce the molecular gap as well as the range of motion of the chain segment. and the volume of the melt. In this way to increase the density and the force between the molecules, it can improve the shrinkage and internal quality of the product, so as to much more internal stress. So under the premise of ensuring the appearance quality of the product, try to choose a lower holding pressure.
If the holding time is too long, it is easy to overfill the material, the molecular gap becomes smaller, and the internal stress becomes larger; if the holding time is too short, the product is prone to shrinkage and the size is unstable. The holding time should be set based on the shortest time when the product weight does not change as the best holding time.
ABS profile extrusion dies temperature: The recommended mold temperature is 60-80°C. Higher mold temperature tends to produce good flow, higher weld line strength, and smaller product internal stress, but the molding cycle will be appropriately extended.
If the mold temperature is lower than the recommended temperature, the internal stress of the product will be too high, which will reduce the performance of the product, and may cause product embrittlement, screw hole cracking, or spray paint cracking.