defects of injection transparent parts
defects of injection transparent parts
Transparent parts of molten spots, crazes, cracks, polystyrene and plexiglass can sometimes see some glittering filamentous crazes through the light. These crazes are also called bright spots or cracks.
This is due to the stress generated in the vertical direction of the tensile stress, and the difference between the completion rate of the non oriented part and the heavy flow orientation of the right polymer molecules.resolvent:
Eliminate the interference of gas and other impurities and fully dry the plastic.
Reduce the material temperature, adjust the material barrel temperature in sections, and appropriately increase the mold temperature.
Increase the injection pressure and reduce the injection speed.
Increase or decrease the pre plastic back pressure and reduce the screw speed.
Improve the exhaust condition of runner and cavity.
Clean the nozzle, runner and gate for possible blockage.
Shorten the molding cycle and eliminate crazing by annealing after demoulding: keep polystyrene at 78 ℃ for 15 minutes or 50 ℃ for 1 hour, and heat polycarbonate above 160 ℃ for several minutes.
