Experimental investigation and numerical simulation of micro-EDM of bulk metallic glass with focus on crater sizes

The Effect of Discharge Current and Pulse-On Time on Biocompatible Zr-based BMG Sinking-EDM

“…Figure 1(b) shows the surface roughness as a representative of surface quality is increased significantly at the highest value of 5.50 µm, if the higher current was applied, irrespective to the other parameter, indicating the deterioration on surface quality occurred when using high discharge energy during machining. This phenomenon is similar with those occured on previous studies where the increased discharge energy, which is proportional with the current, inducing the higher machining efficiency and the development of the larger size of the crater on the machined surface [18][19][20]. This larger crater size, correspond to the high amount of material melting during discharge mechanism (pulse-on time).…”

“…The current represents discharge energy determining heat generation during spark material removal mechanism, where the melting and evaporation on the workpiece surface occurred at higher level induced by high discharge temperature. This phenomenon was also reported by previous studies [18,19]. Additionally, by increasing discharge energy, the debris deposited in the tool-workpiece gap was also increased.…”

“…On the other hand, the micro-porous was also found on the machined surface using 12 A and 150 µs, as shown in Figure 3 (b). The micro-porous was possibly formed by irregular overlapping craters distribution induced by excessive melting due to high discharge energy, as also stated by several other studies [18,19,23]. These crater size and microporous appearance were responsible on the increased surface roughness on machined BMG; therefore, when the surface quality becomes the essential criteria, such as a finishing step, the discharge energy should be maintained as low as possible.…”

“…As reported before, spark occurred during machining characterized the discharge energy transmitted on the workpiece surface and became the dominant driving parameter for material removal mechanism on EDM cutting, beside of the dielectric flushing system [17]. Nowadays, micro-EDM was preferable to be applied in order for avoiding crystallization of BMG cutting because of its low discharge energy, based on several reports [18,19]; however, the method is considered inappropriate for cutting macro-dimensional shape on medical devices; therefore another technique is needed to cut BMG at a larger scale.…”

Microhole Forming and Creep Behavior of Fe‐Based Nanocrystalline Alloys under Laser Dynamic Impact

“…Micro‐electrodischarge machining (MEDM) is commonly used in various materials as noncontact processing. However, during the processing of amorphous alloy microholes with low thermal conductivity, heat‐affected zones and recast layers form at the edges of the microholes, and debris affects the surface quality . Laser beam drilling is a widely applicable processing technology that can process the microholes of many materials with complex contours.…”