Modeling of material removal morphology and prediction of surface roughness based on WEDM successive discharges

Abstract

In this paper, a successive discharges material removal model is proposed to predict the surface roughness of the EN-GJL-250 (Grey Cast Iron) under different discharge parameters of Wire-cut electrical discharge machining (WEDM). Firstly, the finite element method (FEM) was used to analogue simulation the distribution of material surface temperature and flow field in the WEDM single pulse discharge machining process. According to the principle of energy conservation, the surface morphology and characteristic parameter size of a single pulse crater under different discharge parameters are simulated. Secondly, the discharge position is determined by the minimum gap width between the initial surface of the workpiece and the electrode wire during the establishment of the material removal model. Simulation results show: The magnitude of the single pulse discharge energy has an important influence on the morphology and characteristic size of the crater. Due to the different discharge energy, the increasing trend of crater radius, depth and flanging height is not synchronized, and the increase of crater radius is more obvious and rapid. Meanwhile, the final morphology of the WEDM machined surface is determined by the morphology size of a single pulse crater and the location distribution of discharge points. Finally, the same discharge parameters are used to verify the surface quality of machined materials. Experimental results show: The surface morphology of the WEDM workpiece is in good agreement with the material removal model, and the average relative error of surface roughness between the simulation results and the experimental results is 8.26%.

Parametric Optimization and Influence of Near-Dry WEDM Variables on Nitinol Shape Memory Alloy

“…Enhancement in current further improved the discharge energy. It is further converted into thermal energy which enhances the sparking frequency during NDWEDM [ 81 ]. The formation of recurring spark leads to the melting and vaporization of work material thereby, erosion rate during machining [ 82 ].…”

Progress in Simulation Modeling Based on the Finite Element Method for Electrical Discharge Machining

“…It also shows the temperature distributions across the entire top surface (indicated by a white dashed line) and the interface between the melting material and the substrate (also marked by a white dashed line) [52]. Li et al [56] developed a thermal-fluid coupling model for the single pulse discharge process, utilizing Gaussian heat sources. Their findings indicated that the continuous discharge EDM material removal model exhibited a SR prediction error of 8.26%.…”

Recent Trends and Developments in the Electrical Discharge Machining Industry: A Review

“…Figure 11(b) shows the development of numerical models based on the literature data reviewed. Most modern works are taking into account the wear of the workpiece within the framework of the technological process [10,41,54,58,62,76,79,83,84,86,91,110,115,135,187,188,191,197,[201][202][203][204][205]. The main technology used in modeling surface changes is the "killing" of elements when a certain material melt temperature is reached with the formation of a new surface type [54,133,135,191,201].…”

“…It can be noted that a fairly large number of studies consider the formation of a single crater from a single discharge [41,62,76,79,82,133,135,184,185,197,202,[210][211][212]. Construction of more complex models of shaping is impossible without understanding mathematical description and modeling of the process of crater formation as a whole [202]. There are digital solutions associated with the modeling of multi-pulse processing [62,203,213].…”