OBRABOTKAMETALLOV technology Vol. 27 No. 2 2025 Introduction Advanced non-conventional electrical discharge machining (EDM) is an electro-thermal process where material is removed from a workpiece by means of electrical discharges (sparks). EDM is widely used in the manufacturing of shape memory alloy (SMA) components, ceramics, and composite materials due to its ability to provide high precision and geometric complexity [1]. EDM is considered one of the most effective methods for processing difficult-to-machine materials such as high-strength, brittle, and hard alloys, as it does not require the application of mechanical force [2]. During the EDM process, thermal energy required for material removal is generated by electrical sparks occurring in a dielectric fluid. Localized, intense heating caused by continuous electrical breakdowns leads to melting and vaporization of the workpiece material. The dielectric fluid performs several important functions: removing erosion products, cooling the workpiece, and preventing arc discharges [3]. Two types of EDM machines are distinguished: sinker EDM and wire EDM (WEDM). The selection of a specific type of EDM is determined by the application requirements, as well as the material properties and geometric parameters of the part being manufactured [4]. EDM enables the machining of electrically conductive materials with a wide range of mechanical properties. Due to its high precision and ability to meet specified surface quality requirements, EDM technology is in demand in the aerospace, automotive, biomedical industries, and in the manufacture of tools and dies [5]. EDM efficiency is determinedbynumerous process parameters, includingdischarge energycharacteristics (pulse-on time and pulse-off time, current, gap voltage, spark gap), the type of electrode and dielectric fluid, flushing pressure, and cycle duration. Optimizing these parameters is a key factor in achieving maximum productivity (material removal rate), minimum surface roughness, and increased tool life [6]. Research in the field of EDM machining of advanced materials often includes parametric studies aimed at studying the influence of process parameters on material removal rate (MRR, Q), surface roughness (SR, Ra), and tool wear rate (TWR, υh). These studies typically include an assessment of the underlying physical processes accompanied by parameter optimization methods. The results of such studies enable the development of EDM technologies suitable for high-performance applications requiring precise processing of difficult-to-machine materials [7]. Due to their improved mechanical and thermal properties, shape memory alloys (NiTi), Monel alloy (NiCu), and beryllium bronze (BeCu) are finding increasingly wide application, which increases the demand for EDM as an effective method for their processing. NiTi shape memory alloys exhibit both the shape memory effect and superelasticity, making them in demand in biomedical devices, the aerospace industry, and robotic systems [8]. Important properties of NiTi alloys include high corrosion resistance, biocompatibility, and the ability to elastically recover after deformation. EDM is the preferred method for processing such materials, as conventional machining methods are often ineffective due to the high strength and toughness of these alloys. The NiCu material known as Monel alloy is characterized by excellent corrosion resistance combined with high mechanical strength and thermal stability. These properties make Monel alloy suitable for applications in marine environments, the chemical industry, and the aerospace sector. The difficulty in machining Monel alloy is related to the effect of strain hardening and high toughness, which makes EDM an optimal solution. Beryllium bronze (BeCu) combines high strength, thermal conductivity, and corrosion resistance. The primary application areas of this alloy include electronic connectors, aerospace components, and tooling elements for injection casting. Hardening of beryllium bronze increases its strength, but the material becomes difficult to machine due to heat generation and tool wear [9]. To enhance the efficiency of the EDM process and reduce machining time, it is necessary to increase the material removal rate (MRR, Q). Surface roughness (SR, Ra) is an important quality indicator that determines the smoothness of the machined surface. SR is influenced by factors such as discharge energy, spark gap size, and dielectric fluid flushing conditions. When used in areas requiring precision machining, high surface quality requirements are imposed, which are achieved by minimizing SR values.
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