Time-dependent Optimal Heater Control Using NURBS and RSM

Thermoforming is one of the most versatile and economical processes available for shaping polymer products. To improve the competitive power of the products, the manufacturing fee should be continuously reduced. But, the required heat can not be freely reduced because of the temperature difference between surface and center of the sheets. In this paper, an optimal design using NURBS and RSM was carried out for decreasing the required heat. NURBS were used to design shapes for the time-dependent variation of heater power inputs, and D-optimal method was used to select experimental points to construct the response surfaces. The optimal results show that the developed method in this study can be used to reduce the required heat in the forming temperature range by the end of the heating process.