Abstract
The deformation pattern and the thickness distribution of a product in a thermoforming process with blowing, stretching and vacuuming had been obtained by computer simulation and presented in former reports. Through the simulation it had been confirmed that the consideration of the distributed temperature in a specimen sheet and the variation of the temperature in successive stages of the process were most important factors. Only a small difference of the temperature in a specimen sheet influenced to the thickness distribution of the product. Then, to controll the temperature distribution of a specimen sheet was expected to be able to controll the thickness distribution of the product. For the forming of a square box from a rectangular sheet of acrylic-modified PVC, the above expectation was tried for the confirmation by computer simulation with non-linear elastic FEM and it was succeeded to optimize the thickness distribution of the product by the adjustment of the temperature distribution of the specimen sheet. Evaluations of the strengths of the products with some different thickness combinations were also done by linear FEM. The optimization procedure was proposed in this report.
