Đang chuẩn bị liên kết để tải về tài liệu:
A numerical model of the EDM process considering the effect of multiple discharges

(BQ)In this paper a new contribution to the simulation and modelling of the EDM process is presented. Temperature fields within the workpiece generated by the superposition of multiple discharges, as it happens during an actual EDM operation, are numerically calculated using a finite difference schema. The characteristics of the discharge for a given operation, namely energy transferred onto the workpiece, diameter of the discharge channel and material removal efficiency can be estimated using inverse identification from the results of the numerical model. The model has been validated through industrial EDM tests, showing that it can efficiently predict material removal rate and surface roughness with errors below 6%. | ARTICLE IN PRESS International Journal of Machine Tools & Manufacture 49 (2009) 220–229 Contents lists available at ScienceDirect International Journal of Machine Tools & Manufacture journal homepage: www.elsevier.com/locate/ijmactool A numerical model of the EDM process considering the effect of multiple discharges ´ B. Izquierdo Ã, J.A. Sanchez, S. Plaza, I. Pombo, N. Ortega Faculty of Engineering of Bilbao, Alameda de Urkijo s/n, 48013 Bilbao, Spain a r t i c l e in f o a b s t r a c t Article history: Received 18 February 2008 Received in revised form 17 November 2008 Accepted 18 November 2008 Available online 3 December 2008 The electrical discharge machining (EDM) process is, by far, the most popular amongst the nonconventional machining processes. The technology is optimum for accurate machining of complex geometries in hard materials, as those required in the tooling industry. However, although a large number of EDM machines are sold every year, scientific knowledge of the process is still limited. The complex nature of the process involves simultaneous interaction of thermal, mechanical, chemical and electrical phenomena, which makes process modelling very difficult. In this paper a new contribution to the simulation and modelling of the EDM process is presented. Temperature fields within the workpiece generated by the superposition of multiple discharges, as it happens during an actual EDM operation, are numerically calculated using a finite difference schema. The characteristics of the discharge for a given operation, namely energy transferred onto the workpiece, diameter of the discharge channel and material removal efficiency can be estimated using inverse identification from the results of the numerical model. The model has been validated through industrial EDM tests, showing that it can efficiently predict material removal rate and surface roughness with errors below 6%. & 2008 Elsevier Ltd. All rights reserved. Keywords: EDM Thermal model Roughness