Free Thermal Deformation Of Injection Molded Parts After Ejection

As an important defect of injection molded parts, warpage has been received awidely attention. Currently, researchers have conducted in-depth studies on warpagehappened during the injection molding process, and the mature commercial software asa support to optimize the design has been developed. However, in practice, the freecooling process in demolding state will generate seriously secondary shrinkagedeformation due to the high demolding temperature, which lead to a decrease of thequality of the plastic parts. But such a warpage is usually ignored and rarely studied.This paper studied the factors that impact the warpage of injection molded parts atdemolding state using physical experiments and numerical simulation. Combined withspecific parts and by taking into account the warpage of injection molded parts atdemolding state and warping deformation in the injection molding process, the moldingprocess were optimized and the quality of the part were improved.①The causes of residual thermal stress in the injection molding of plastic partsafter ejection were analyzed. Its influence on the warpage was also discussed. Theinfluencing factors of the warpage of injection molded part at demolding state weresummarized.②Through the plastic pieces of plate buckling experiment and numericalsimulation, the temperature, thickness, structural components, as well as externalenvironmental factors on the impact of the warpage of plastic parts after ejection wereanalysised. The results of numerical simulation and experimental were comparison andanalysis. Which is verifies the feasibility that the numerical simulation technology insimulated warpage of plastic parts after ejection.③For a specific parts of motorcycle seat bottom plate, this paper analyzes bucklingdeformation of the parts in different materials, ejection temperature, thickness and theexternal environment. Combined with the injection molding process, the warpage ondemolding temperature in different process conditions ejection was analyzed. Throughnumerical simulation, taking the injection process warpage and demolding warpage asan index, the method of orthogonal experiment was used to analyze the impact ofvarious factors on the warpage and optimize the molding process.