Abstract

Electric discharge machining (EDM) is a nontraditional machining process based on the thermal erosion of the electrically conductive workpiece and tool electrodes. The product cost manufactured by the EDM process mainly depends on the tooling cost, which comprises the cost of tool material, tool fabrication, and tool maintenance. The properties of tool material affect the machining performance parameters like material removal rate (MRR), tool wear rate (TWR), and surface roughness. The performance parameters are also influenced by the tool geometry, tool fabrication method, and the way by which both tools and workpiece interact with each other. In the EDM process, tool wear is difficult to avoid and high TWR decreases the accuracy of the machined parts. Therefore, to obtain the desired accuracy it is necessary to calculate TWR and provide wear compensation. The tool electrode fabrication method also decides the TWR. Tool electrodes are generally manufactured by metal forming techniques like forging and drawing, other than that, powder metallurgy, additive manufacturing are also being used. The process performance of the tool can be improved by cryogenic treatment and coating of the tool electrodes. This review provides the literature survey about the different types of tools used in the EDM process, methods of fabrication, tool wear types; measurement and compensation techniques.

摘要

放电加工 (EDM) 是一种基于导电工件和工具电极的热腐蚀的非传统加工工艺。EDM 工艺制造的产品成本主要取决于模具成本，包括模具材料、模具制造和模具维护成本。刀具材料的特性会影响加工性能参数，如材料去除率 (MRR)、刀具磨损率 (TWR) 和表面粗糙度。性能参数还受到刀具几何形状、刀具制造方法以及刀具和工件相互作用方式的影响。在电火花加工过程中，刀具磨损难以避免，高TWR降低了加工零件的精度。所以，为了获得所需的精度，必须计算 TWR 并提供磨损补偿。工具电极的制造方法也决定了 TWR。工具电极通常通过锻造和拉拔等金属成型技术制造，除此之外，还使用粉末冶金、增材制造。工具的工艺性能可以通过工具电极的低温处理和涂层来提高。本综述提供了有关 EDM 工艺中使用的不同类型刀具、制造方法、刀具磨损类型的文献调查；测量和补偿技术。增材制造也被使用。工具的工艺性能可以通过工具电极的低温处理和涂层来提高。本综述提供了有关 EDM 工艺中使用的不同类型刀具、制造方法、刀具磨损类型的文献调查；测量和补偿技术。增材制造也被使用。工具的工艺性能可以通过工具电极的低温处理和涂层来提高。本综述提供了有关 EDM 工艺中使用的不同类型刀具、制造方法、刀具磨损类型的文献调查；测量和补偿技术。