Flash Defect

Flash is an injection molding defect that occurs when molten plastic escapes from the mold cavity and solidifies along the parting line, ejector pins or other mold openings. The excess material creates a thin layer or protrusion of plastic on the finished part.

Flash is one of the most common injection molding defects and is typically caused by excessive injection pressure, worn tooling, insufficient clamp force or improper mold fit. While flash can often be removed through secondary operations, it increases production costs and may affect part appearance, dimensional accuracy and assembly performance.

M. Holland helps customers identify material and processing solutions that improve molding consistency and reduce common manufacturing defects.