A novel method towards approximation of the temperature distribution in electric discharge machining of Ti-6Al-4V by up-scaling approach

作者：Shahri Hamid Reza Fazli; Mahdavinejad Ramez****i^*

来源：International Journal of Advanced Manufacturing Technology, 2018, 96(1-4): 503-520.

DOI：10.1007/s00170-018-1578-9

• Dry-EDM
• Up-scaling method
• Laser process
• Temperature distribution
• FEM
• HAZ

Measurement of the temperature in electric discharge machining (EDM) process is mostly accompanied with numerous difficulties. On the one hand, although both numerical and analytical methods estimate the temperature distribution of the workpiece, they usually are accompanied with simplifying assumptions resulting in errors. On the other hand, experimental tools like thermocouples are not able to measure the precise temperature. This study addressed this issue by introducing a new approach for estimating the temperature distribution of the Ti-6Al-4V. Two different cases were followed in this study. Firstly, an up-scaling method was applied to model the heat source on the workpiece for exploring the temperature distribution based on non-dimensionalized equations with constant thermal conductivity. Critical parameters of the EDM process, i.e., heat flux radius and time, were scaled up enough to facilitate measuring the temperature. Then, an equivalent laser beam with Gaussian heat source was particularized according to the prototype in terms of heat equation and boundary conditions. The temperature curves were then measured by IR thermography technique to estimate the boundaries of fusion zone and heat-affected zone. The obtained analytical results of up-scaled model were then compared with FEM results. Secondly, unlike the majority of theoretical models, the present study considered the variable thermal conductivity in up-scaling procedure to estimate temperature results more precisely. To this end, dimensional analysis and Buckingham's Pi theorem were used to scale up the single-spark dry-EDM. The comparison between the results revealed that a good agreement between the temperature results of proposed model and the experimental results was found, and the model could predict the crater profile of EDMed specimen precisely.

• 出版日期2018-4