Critical review on sustainable techniques in electrical discharge machining

Abstract Electric discharge machining (EDM) can be used to cut complex parts and hard materials, making it one of the most popular machining processes today. However, the energy efficiency of EDM is low compared with conventional methods such as turning, milling and grinding. In addition, the gas and noise emissions of the EDM process affect the environment and the health of operators. This paper reviews the research trends in the latest sustainable techniques in EDM. First, a detailed review of existing EDM techniques for enhancing energy efficiency conducted. The review considers three aspects: energy distribution, the relationship between process parameters and specific discharge energy, and the effects of external field assistance. Second, the dry-EDM process-a clean manufacturing technique is introduced and its environmental impact is discussed. The machining performance indicators of dry-EDM, such as the material removal rate, tool wear ratio, surface topography, and microstructures, are compared with those of conventional EDM. Next, the indicators of gas and noise emissions in EDM are proposed to evaluate the sustainable manufacturing process. The relationship between the process parameters and emission indicators is reviewed, and multi-optimization considering machining noise is discussed. Finally, the impact of sustainable techniques in EDM on the environment, society, and economy are discussed, as well as the application costs of these techniques. Some directions for future research are also proposed.