Surface integrity evolution and machining efficiency analysis of W-EDM of nickel-based alloy

Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques

“…Among non-traditional machining process electric discharge machining (EDM) is considered as relatively good alternative having no material hardness and channel shape restrictions [224,225]. But there are also number of problems linked with EDM and wire-EDM such as low productivity, high tool wear rate, lack of precision due to tool wear, unsuitable for batch production or multi-channels [226], thick recast layer (from 2.5 to 30 µm) [227], heat affected layer of 40-100 um [227], thick white layers (6-8 µm) with micro-cracks [228], poor surface integrity [229] and necessary post processing requirements [230]. Chemical etching is another alternative for the fabrication of micro-channels but it offers troubles of having high aspect-ratio micro-channels [231].…”

“…The width, depth, and length of each microgroove were about 150, 300, and 50 mm, respectively, and 16 grooves were produced on each plate. Thick white layers (6-8 µm) with micro-cracks [228] Micro-cracks [257,258] Poor surface integrity [229] Post processing requirements [230] Less fatigue life [259] ECM High material removal rates Good surface integrity [261] Less heat affected zone [262] High tooling cost Suitable for large batch sizes [226] Salt film on machined surface [261] Selective corrosion due to the formation of a porous salt [271] Decrease working time [271] Reductions in vertical and horizontal forces [272] Less stresses in the tools [273] Overlapping grit marks [272] Laser/plasma assisted (cutting, drilling and surface modification) 30 % reduction in cutting force [114] Improved surface roughness 40 % [115,275] Increase in tool life [275,276] No micro-crack during laser surface melting [277] Increase in hardness by laser surface treatment [278] Compressive residual stresses [115] Thicker compressive zone (40-70 µm)…”

“Research Work for Optimization and Effect of WEDM Cutting Process Parameters on Performance Measures- a Literature Review”

“…Micro-cracks exists in white layer of 6-8 µm thickness in RC mode and thin white layers of 0-2 µm free from micro-cracks was observed in TC2 mode. In TC3 mode white layer was invisible [16].A. Goswamiet.…”

“…Stainless steel 304 was employed as work piece; brass wire of 0.25mm diameter was selected as tool along with distilled water which was used as dielectric fluid. Taguchi's L 16 , orthogonal array technique was used for experiments. The input parameters such as gap voltage, wire feed, pulse on time, and pulse off time were selected for optimization.…”

Machining, Joining and Modifications of Advanced Materials

“…There are many techniques to produce above said sizes and shapes of microchannels including both the conventional as well as non-conventional techniques. But there are also number of problems linked with EDM and wire-EDM such as low productivity, high tool wear rate, lack of precision due to tool wear, unsuitable for batch production or multi-channels [226], thick recast layer (from 2.5 to 30 µm) [227], heat affected layer of 40-100 um [227], thick white layers (6-8 µm) with micro-cracks [228], poor surface integrity [229] and necessary post processing requirements [230]. For example, the conventional micro-milling process using micro-tools are commonly used but the high tooling cost, burr formation, material constraints offered by difficult-to-machine materials, chip adhesion, high thrust forces, heat affected zone and striation marks are the obvious drawbacks of conventional micro-milling and consequently restrict the process for precise micro-featuring especially in hard-to-machine materials such as titanium and nickel alloys [215][216][217][218][219].…”