Generally, molding defects are either part design, mold design, or process related. This lesson focuses on processing-related short shots, a condition where portions of a part remain unfilled. The next lesson will cover part and mold design-related short shots. Injection molding is a complex scientific manufacturing process. By following a methodical set-up process, molders aim to minimize or eliminate common molding defects that affect part quality.
Topics in this lesson include: the potential reasons for short shots; how to run various sensitivity analyses to evaluate process parameters affecting short shot conditions; and how melt and mold temperature, cavity fill time, injection velocity profiling, switch-over set-point from filling to packing, and the initial packing pressure affect short shots.