Multiscale Modeling of Sinking-EDM with Gaussian Heat Flux via user Subroutine

The EDM gap phenomena in the microscale time and space domains are very complex and challenging to analyze experimentally. However, the gap phenomena are critical to produce optimal surface integrity for superior performance of EDMed components. Nevertheless, the highly nonlinear transient dynamic process involving time/space-dependent plasma and heat flux has not been well understood. This work presents a multiscale finite element modeling for single discharging of ASP2023 tool steel to incorporate the plasma-induced time/space-dependent Gaussian heat flux via a user subroutine. The long-standing numerical singularity of heat flux in EDM modeling is solved using the innovative functions of discharge current. The effects of discharge duration and current on temperature profiles, crater formation, and dimensions are investigated. The basic mechanisms of superheating and melting can be successfully predicted. In addition, melting front recedes at long discharge duration, while melting front advances at high discharge current.