Sink marks appear when thermal shrinkage of plastics material is not compensated. A sink mark usually appear at rib, boss position, or thickness of product is changed. This post I will explain about cause and sink mark troubleshooting. I. Sink mark causes. + Thickness of product is not equal, samples usually have sink marks at transfer […]
molding defect
injection molding troubleshooting flash defect
Injection molding troubleshooting flash defect usually appears near parting line, gas vent, slide core, or ejector pin. Burr looks like a develop film like a plastic edge. I. Causes of flash injection molding. + Material effect. For example, GF resin always have flash. It is difficult to improve flash. + Mold has gap between the […]
injection molding short shot troubleshooting
In injection molding short shot defect cause by molten plastic does not fill the cavity, product marking is incomplete. I. Cause of short shot. + Molten plastics are stick or cold in runner system. + Mold structure is not good so molten plastics can not fill in the cavity. + In injection molding process, air […]
ejector marks injection molding cause and troubleshooting
In injection molding process, ejector marks is a concave or a convex on the surface. Samples are stick in the mold under force of ejector system, it will create holes on products. Cause of ejector mark. + Sample doesn’t have a draft angle at boss, rib. It is difficult to push sample out of the […]