Our study was devoted to increasing the efficiency of electrical discharge machining of high-quality parts with a composite electrode tool. We analyzed the chemical composition of the surface layer of the processed product, microhardness, the parameter of roughness of the treated surface, residual stresses, and mechanical properties under tension and durability with low-cycle fatigue of steel 15. Our objective was to study the effect of the process of copy-piercing electrical discharge machining on the performance of parts using composite electrode tools. The experiments were carried out on a copy-piercing electrical discharge machining machine Smart CNC using annular and rectangular electrodes; electrode tool materials included copper, graphite, and composite material of the copper–graphite system with a graphite content of 20%. The elemental composition of the surface layer of steel 15 after electrical discharge machining was determined. Measurements of microhardness (HV) and surface roughness were made. Residual stresses were determined using the method of X-ray diffractometry. Metallographic analysis was performed for the presence of microdefects. Tensile tests and low-cycle fatigue tests were carried out. The mechanical properties of steel 15 before and after electrical discharge machining under low-cycle fatigue were determined. We established that the use of a composite electrode tool for electrical discharge machining of steel 15 does not have negative consequences.

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The aim of the present study is to investigate the surface roughness of Electrical Discharged Machined (EDM) samples with Electrode Tool (ET) materials. For the experiments, three different types of ETs were considered which are made of different materials viz. composite, copper, and graphite. Aluminium, low alloy 35GS steel and OT4 titanium alloy were selected as the workpiece materials. Machining parameters used were: current (I) 8 A, voltage (U) 100 V, and pulse duration (Ton) as 150 μs. It was found that the ET made of composite material performs best in EDM of 35GS steel and OT4 titanium alloy. Specifically it was concluded that in the first case, the performance of composite ET is higher than graphite ET by 59 %. Similarly, in the second case, its productivity was found to be 74% and 95% higher when machined with graphite and copper ET respectively. Moreover, the surface roughness values of 35GS steel machined with composite ET was found to be 15% higher when machined with copper and graphite ET. While processing titanium alloy with composite ET, surface roughness values were observed as high as 44% and 25% when machined with copper and graphite ET respectively.

This study investigates the effect of electrolytic plasma processing on the degree of defective layer removal from a damaged layer obtained after manufacturing operations. Electrical discharge machining (EDM) is widely accepted in modern industries for product development. However, these products may have undesirable surface defects that may require secondary operations. This work aims to study the die-sinking EDM of steel components followed by the application of plasma electrolytic polishing (PeP) to enhance the surface properties. The results showed that the decrease in the roughness of the EDMed part after PeP was 80.97%. The combined process of EDM and subsequent PeP makes it possible to obtain the desired surface finish and mechanical properties. In the case of finishing EDM processing and turning, followed by PeP processing, the fatigue life is enhanced without failure up to 109 cycles. However, the application of this combined method (EDM + PeP) requires further research to ensure consistent removal of the unwanted defective layer.

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