The causes and solutions of transparent defects in injection molded products
Melting spots, silver lines, cracks polystyrene, plexiglass transparent parts, sometimes through the light can be seen some shiny filament-like silver lines. These silver lines are also called scintillation spots or cracks. This is due to the stress in the vertical direction of the tensile stress, the use of the right polymer molecules heavy flow orientation and the unoriented part of the folding rate differences show up.
Solution.
(1) Eliminate the interference of gas and other impurities, the plastic is fully dry.
(2) reduce the material temperature, segmentation adjustment of the barrel temperature, appropriate to increase the mold temperature.
(3) Increase the injection pressure and reduce the injection speed.
(4) Increase or reduce the pre-molding back pressure and reduce the screw speed.
(5) Improve the flow channel and cavity exhaust condition.
(6) Clean up possible clogging of injection nozzles, runners and gates.
(7) Shorten the molding cycle, and use annealing methods to eliminate silver patterns after demolding: for polystyrene hold at 78ยฐC for 15 minutes, or 50ยฐC for 1 hour, and for polycarbonate, heat to 160ยฐC or more for several minutes.
