There are two factors affecting the whole transparency, thus causing coarse surface of the injection molded products. One is the poor polishing of mold surface, and the other is the early cooling of melting material. The specific solutions are as follows:
(1) Increase temperature of material, injecting pressure and speed, especially mold temperature. The mold temperature has great effect on surface gloss.
(2) Improve gate location and pay attention to the smooth flowing of material.
(3) Prevent material degradation and uncompleted plasticization.
(4) Extend cooling time and prolong packing time as well.
(5) Prevent gas interference
Analysis on causes of Swelling and Bubbling of Injection Molded Products
After shaping up and de-molding, some plastic products will soon swell or bubble on the back of metal insert or some thick parts, which is because the uncompleted cooling and hardening plastic emits gas and then swells under the effect of internal pressure.
1, Effective cooling: Reduce mold temperature; prolong mold sinking time and lower dryness of materials and processing temperature.
2, Reduce mold filling speed, decrease cycle of period and cut down flow resistance.
3, Increase packing pressure and time.
4, Improve the condition that wall surface is too thick or its thickness changes greatly.