Study of surface integrity and machining performance during main/rough cut and trim/finish cut mode of WEDM on Ti–6Al–4V: effects of wire material

Abstract

Due to increased demand of dimensional accuracy and high precision of manufactured parts, wire electrical discharge machining (WEDM) became very popular, especially for 'difficult-to-cut' materials like titanium alloys. Grade 5 Ti alloy (Ti-6Al-4V) has enormous application in aerospace and biomedical fields. WEDM performance of Ti-6Al-4V is somewhat restricted due to its poor thermal conductivity, formation of hard and brittle carbide-/oxide-rich layer and often surface cracking which affect fatigue performance of the part product. Therefore, multi-cut strategy is adapted to mitigate machining-induced defects. The multi-cut mode consists of one main/rough cut followed by a number of trim/finish cuts. Aspects of surface integrity of the WEDMed Ti-6Al-4V obtained in different modes of cut are delineated in this reporting. Three slots are produced: (1) main cut; (2) main cut followed by one trim cut; and (3) main cut followed by two trim cuts using uncoated brass wire and zinc-coated brass wire, respectively. Surface morphology along with topographical features including roughness average, crack density, recast layer thickness, material immigration, residual stress and micro-indentation hardness is studied. Results obtained thereof are analysed with relevance to kerf width, material removal rate and wire wear.

Milling Microchannels in Monel 400 Alloy by Wire EDM: An Experimental Analysis

“…Considering brevity, the SEM images are only presented for the low and high values of those parameters (TON, TOFF, VGAP) which showed a high influence on the surface roughness parameters. From Figure 10a-e, the surface morphology of the microchannels reveals characteristics such as microcraters, microvoids, microglobules, resolidified material, microcracks and microholes, and similar defects were also reported in the previous studies [25,32,33]. The distribution of the microcracks on the WEDM machined surface was small.…”

“…For measuring the recast layer thickness, SEM images of the cross-sectioned samples were taken. The average recast layer thickness was calculated as the recast layer area measured from the SEM micrograph divided by the micrograph length, as illustrated in [25]. The area of the recast layer was determined through manual inspection, and later using the ImageJ software (National Institutes of Health, Bethesda, ML, USA).…”

“…Micromachines 2020, 13, x 14 of 18 [34,35]. It is clear that the recast layer thicknesses are not uniform; therefore, the average recast layer thickness is reported [25]. The thickness of the recast layer decreases with the pulse-off time, as shown in Figure 14c-d. Higher pulse-off time provides more time to wash out the molten material from the machining surface, and thus, reduces the recast layer thickness.…”

Experimental investigation on WEDM performance analysis using grey-fuzzy integrated with TLBO algorithm for Inconel 625: comparison with GA and SA

“…It has been observed that the presence of irregular or uneven shapes of debris, melted material deposition, craters, micro-cracks, spherical droplets (SD) and pockmarks on the WEDMed surface. The previous authors also reported similar studies Kumar et al (2014), Jadam et al (2019). The irregular or uneven shapes of debris are formed due to the unflushed molten materials by dielectric flushing, and it re-solidified on the surface.…”

Experimental investigation and optimization of machining performance characteristics during WEDM of inconel 718: On evaluation of wire electrodes and advanced parameter techniques

“…14 The fourth strategy is magnetic effects between the tool and the workpart, 3 and the final strategy is the trim cutting method to decrease the dimensional deviation using WEDM. 6,15 Aforesaid discussed important strategies are the most favorable way to improve corner accuracy. It is observed that most WEDM manufacturers suggest that the modification of process parameters can improve the corner accuracy, 5 and also this statement supported by the above literature.…”