Experimental Study On Residual Stress And Properties Of Polycarbonate Auto Windshield In Injection Compression Molding

Polycarbonate (PC) is an odorless, tasteless and transparent thermoplasticmaterial. And it is widely used in automotive, building materials and other fields.PC windshield appeared in foreign counties first, and there are already manyforeign car companies use PC windshield currently. But in our country, theapplication of the PC windshield in the automobile field is less.Injection compression molding is an advanced form of the conventionalinjection molding method. The products processed by injection compressionmolding have some advantages, like the higher dimensional accuracy and thesmaller residual stress and warping deformation. Until the end of twentieth century,foreign countries began to process the automobile windshield with the injectioncompression molding. But the research on how to apply the injection compressionmolding to the PC windshield is very little in china.Residual stress is a kind of internal stress results from the process of themolding, and is the key factor that influences the properties of products. But theinjection compression molding of PC windshield is a complex physical process, andthe any change of the process parameters will change the residual stress and theninfluence the properties of PC windshield. So, it is necessary to study the influenceof process parameters on the residual stress and properties of the PC windshield and theinfluence of the residual stress on the PC windshield’s properties.The experiment scheme of the injection compression molding was made byusing the method of single factor. And in order to get the specimens needed in thefollow-up experiments, this paper processed the products of the PC windshieldaccording to the scheme of the injection compression molding.The flow induced residual stresses in thickness direction of PC windshield wasmeasured to study the influence of the process parameters on the flow inducedresidual stresses through the experiment. The paper got the influence rules of theprocess parameters on the flow induced residual stresses, and analyzed the reasonof the flow induced residual stresses affected by the the process parameters. Inaddition, the paper processed the tensile specimens in the parallel and perpendicularto the flow direction of the melt and studied the influence of the flow induced residual stresses on the mechanical properties of these two directions byexperiments. The paper found that the yield strength and elongation of the specimenin the parallel were bigger than the specimen in the perpendicular. And the paperanalyzed the reason of the phenomenon.In order to study the influence of the process parameters on the thermal-induced residual stresses, the paper studied the thermal-induced residual stresses ofPC windshield in injection compression molding by numerical simulation softwareMoldflow and verified the validity of the simulation results by the solvent ofCarbon tetrachloride. The paper got the influence rules of the process parameters onthe thermal-induced residual stresses, and analyzed the reason of the thermal-induced residual stresses affected by the the process parameters.The paper tested the mechanical and optical properties of PC windshield byexperiments to get the influence rules of the process parameters and the residualstress on the thermal-induced residual stresses and analyzed the reason of thethermal-induced residual stresses affected by the the process parameters.