The injection molding process is a complex 3-dimensional polymer flow and transient heat exchange manufacturing process. Part design, mold design, and the molding process are all intrinsic to a successful outcome. This lesson focuses on gas and air entrapments, a common molding defect that can create numerous issues including burn marks, short shots, and blemishes in molded parts. Optimizing part geometry and mold design is essential for avoiding entrapments.
Topics in this lesson include: the causes and possible solutions for entrapment during the filling process; how race tracking and hesitations can cause entrapments; how internal venting may be a solution for entrapment conditions; and how wall thickness variations can cause entrapments.