Has good tensile strength, impact strength, rigidity, wear resistance, chemical resistance, surface hardness and other properties.
Melting spots, silver lines, cracked polystyrene, transparent nylon parts of plexiglass, sometimes through the light can see some shiny silk-like silver lines, these silver lines, also known as bright spots or cracks. This is due to the stress in the vertical direction of the tensile stress, and the difference in the rate of collapse of the right-to-weight polymer molecules with respect to the non-oriented portion is manifested.
Solution:
(1) To eliminate the interference of gas and other impurities, and to fully dry the plastic.
(2) Reduce the temperature of the material, adjust the temperature of the barrel in sections, and appropriately increase the mold temperature.
(3) Increase injection pressure and reduce injection speed.
(4) Increase or decrease pre-plastic back pressure to reduce screw speed.
(5) Improve the flow path and cavity exhaust conditions.
(6) Clear up possible blockages in the nozzles, runners, and gates.
(7) Shortening the molding cycle, after annealing, the annealing method can be used to eliminate the silver streaks: For polystyrene at 78°C for 15 minutes, or 50°C for 1 hour, for polycarbonate, heat up to 160°C for several minutes .
