Splay Marking and Staining Splay marking and staining look unrelated, but both print the melt’s history onto the part surface. Splay is a process fault. Silver streaks fan from the gate where the melt front lost pressure. Staining is a…
Splash Marks, Mica Marks, Silvering Silver streaks radiating from the gate, like mica flakes frozen in the plastic — that is splash marking, also called silvering. The streaks are volatiles that vaporized at the melt front and condensed on the…
Short mouldings The causes of short mouldings are many and varied and are sometimes difficult to diagnose. It is,for example, perfectly easy to flash a mould and still obtain a short moulding. On the basis that the same property,too low…
Flow Marks and Poor Surface Finish Flow marks are wavy lines frozen into the part surface where the melt front hesitated or turned turbulent. They do not weaken the part. They ruin its appearance, which is enough to scrap a…
Flash in Injection Molding: Causes and Fixes Flash is plastic escaping where the mold should seal. You see it as a thin fin along the parting line, around ejector pins, or at slider shut-offs. The cause is always one of…
Cracking, delamination, and distortion look like three unrelated defects. They share one root family: stress the molding cannot carry. Cracking needs stress plus an aggressive environment. Delamination needs stress plus a weak layer. Distortion needs stress plus premature handling. Remove…
Burn marks What is Burn Marks If an area of a moulding becomes the oxidized, discolored, or blackened, the first thing to do is to examine the venting of the mould. Air trapped in the mould is heated to a…
