Heat ABS injection molding depends on the key?

Heat ABS resin molding process is more complex, due to the heat resistance of ordinary ABS is not good enough, now by adding ɑ-methyl styrene copolymer and N-phenyl maleimide copolymer and other heat-resistant agents developed A series of heat-resisting ABS resins with a heat distortion temperature (HDT) of 90-120 ° C. Due to the high rigidity of the benzene rings and N-phenyl groups in the molecular structure of the heat-resistant ABS, heat resistance is also increased while molecules The steric hindrance of the chain reduces the relaxation rate of the molecular chain and makes it easy for the product to have a large internal stress, resulting in defects such as stress cracking, stress whitening and brittleness of the product, etc. Therefore, The key to injection molding.

For the design of the product mold, the wall thickness of the product should be uniform, the difference of the wall thickness of the ABS product should be controlled within 25%, and the local stress concentration should be prevented to prevent the difference of the wall thickness from being too large, the R angle or additional stiffener , To prevent the column from breaking Testing Center Expert analysis, usually, ABS heat-resistant resin in the storage process will absorb moisture in the air, water absorption with the air humidity changes, generally less than 0.4%, so the material must be fully dried.

Dwell time is set according to the gate with the cooling to complete its curing, the screw is no longer re-push the molded product pressure is applied to the time. Dwell time is too long, easy to fill too much material, the molecular gap smaller, within The stress becomes larger, the dwell time is too short, the product tends to shrink, the size is unstable, and the dwell time should be set as the best dwell time with the shortest time when the product weight no longer changes.

The mold temperature should be noted that if the mold temperature is lower than the recommended, it will lead to excessive stress within the product will reduce the performance of products, products may appear brittle, screw hole cracking or paint cracking and other undesirable phenomena. Testing Center specializes in a variety of plastic material composition, Formulation analysis And material testing, testing department of technical personnel to remind, for heat-resistant ABS, packing pressure and time setting is reasonable, a direct impact on the size of the workpiece stress in the molding heat ABS using mold temperature control Mold temperature, the proposed mold temperature is 60-80 ° C. Higher mold temperature, tend to produce good flow, higher weld line strength, smaller product stress, but the molding cycle will be extended.

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