In the process of injection molding, dimensional deviations in plastic parts are a common issue. The size of plastic parts is typically influenced by factors such as the type of plastic material (including additives), the mold shrinkage index, and the injection molding conditions.

Given that the injection mold and plastic material are often predetermined, injection molding operators usually rely on adjusting the molding conditions to correct the dimensions of the plastic parts. Dimensional deviations in plastic parts can stem from various factors, including unreasonable overall shrinkage of the part, differences in dimensional changes along the length and width, internal dimensional variations within the part, and size discrepancies between the mold cavities.