Study on the warpage of plastics vacuum-forming process

A series of experiments was carried out to comprehensively study the effect of technological parameters including mold geometry (depths of draw, the s hape of impression), initial forming temperature and material properties on the warpage of plastics vacuum-formed parts. During the process of plastic s vacuum-forming, the thermoelastic FEM model was adopted to analyze the wa rpage at the cooling stage and the rigid visco-plastic FEM model was adopte d to analyze the deformation at the deforming stage. The 3-D temperature fi elds are computated using Calerkin FEM code with proper selection of the pa rison's thermal properties and appropriate disposals of dynamic heat conclu sion boundary condition, latent heat and deformation heat. The simulation r esults of warpage match the experimental results of the sample part quite w ell.