After the plastic parts are molded, some defects may occur, which will affect the assembly efficiency or the performance of the whole machine, and there will be certain differences from the predetermined quality standards (inspection standards), which cannot meet the company's quality requirements. In addition to strengthening the quality awareness training of employees and timely handling of defective accessories (such as selection, processing, etc.); these defects may be caused by the following aspects: molds, raw materials, process parameters, equipment, environment, and personnel. The defects are summarized following article -1.