A study on thermal characteristics of non-contact hot-tool for rapid feature detailing (RFD) process

The rapid feature detailing (RFD) process utilizing the non-contact hot-tool has been developed to create detailed shapes on the surfaces of VLM-ST parts. The dimensional accuracy of the detailed shape is significantly dependent on process parameters such as heat input, shaping speed, and the gap between the hot-tool and EPS foam. The objective of this study is to investigate the influence of process parameters on thermal characteristics such as kerfwidth, depth of cut and temperature distribution in the EPS foam in order to obtain controllable conditions for feature detailing and to improve dimensional accuracy of the process. Several experiments were carried out to find the relationships between process parameters and kerfwidth, and between process parameters and depth of cut. Numerical analyses were performed to investigate the influence of process parameters on temperature distribution in the EPS foam sheet and to estimate the amount of the sheet melted away. In order to develop a numerical model of the RFD process, a radiation heat source model utilizing view factors and an anisotropic thermal conductivity are introduced. In terms of kerfwidth and depth of cut, the results of the numerical analysis were in agreement with the experimental results. From this, it has been confirmed that the proposed numerical model is an effective tool to predict the influence of process parameters. Based on these results, the controllable operating conditions for the RFD process are described.