Study Of The Residual Stresses Measurement In Injection Molding Products By Layer Removal Method

Injection products are applied more and more widely for their high cost performance. But the complex heat history lead to the formation of residual stress in the injection molding process. The existence of residual stress will result in the craze, making the optical performance and impact strength of products decrease and affecting their application. The residual stress are generally caused by uneven flow and colling, called flow residual stress and thermal residual stress. Due to the thermal residual stress is one order of magnitude bigger than the flow residual stress, the thermal residual stress was studied in this paper.Based on the amorphous polycarbonate (PC) as the research object, main work is as follows:1. The PC splines were prepared by injection molding with different processing parameters, firstly. Then Layer removal method was carried out and the deformation was measured for all samples.With the mechanics analysis, the collected data of deformation were converted to curvature, then the values of residual stress along the thickness direction of PC samples were estimated using the derived residual stress formula. The effects of injection pressure, holding pressure and mold temperature on the residual stress were discussed respectively.2. The residual stresses under different processing parameters were calculated using Moldflow technology. The mean value of residual stress of each layer were estimated. Then the experimental results and simulation results were compared in the paper.3. The chain segment will rearrange during annealing and releasing part of residual stress. Annealing treatment was carried out on part of PC samples, and the effects of annealing on the residual stress were studied.