Suspended SiC particle deposition on plastic mold steel surfaces in powder-mixed electrical discharge machining

Abstract

The discharge gap phenomena in powder-mixed electrical discharge machining are examined using SiC powder mixing in water dielectric liquid. Surface modifications on machined work materials are investigated by means of optical, scanning electron microscopy and energy-dispersive spectroscopy. The experimental studies revealed that the surface morphology drastically affected the additives as means of secondary discharges and particle migration from dielectric liquid. Such mechanisms do not occur randomly and indicate a robust dependency with respect to powder suspension concentration, pulse on duration and current. The influence on discharge transitivity with respect to suspended particle concentration is noted with pock shape development due to secondary discharges followed by an intermediate stage signifying a sudden increase in particle migration from the dielectric liquid. The particles decomposed on the surface at specific operational conditions demonstrating the possibility of methodical surface alloying using the process. Finally, the mechanisms involved were elaborated with respect to operational parameters and discussed based on the experimental results.

Surface modification and functionalization by electrical discharge coating: a comprehensive review

“…Prakash and Uddin [3] reported that a high HA powder concentration (15 g l −1 ) with a high peak current (15 A) and low pulse duration in deionised water deposits a uniform and crack-free HA layer on the surface of the β-phase Ti implant. However, this conclusion was opposed by Ekmekci et al [126], who found that the surface cracks are formed by the diffusion of C into the recast layer from the particle and that the penetration of C particles decreases along with the peak current. Therefore, the cracking of the coating surface reduces along with a lower peak current.…”

Surfactant and graphite powder–assisted electrical discharge machining of titanium alloy

“…21 Figure 3 depicts that 14-16 g/L graphite powder concentration added into the dielectric fluid reduces the SR at a slow rate due to reducing the diameter and depth of craters of the material. [21][22][23] Although graphite powder concentration of 16 g/L is added to dielectric, RLT is slightly increasing, as observed in Figure 5, as the presence of graphite powder particles within the discharge gap creates two opposing effects that affect the RLT. With the increase in powder concentration and resulting gap enlargement, the ease of plasma expansion lowers plasma over-pressure considerably and allows more molten material retentions.…”

Micro-hardness evaluation for surface alloying of H11 die steel with Cu–Cr–Ni powder metallurgy tool in electrical discharge machining

“…Many methods are reported to improve a particular surface property by alloying the workpiece surface with suitable elements using EDM. Researchers have used sintered or semi-sintered powder metallurgy (PM) electrode, [5][6][7] powder suspended in a dielectric fluid [8][9][10][11] and suitable dielectric fluid 12 for surface alloying. Research is going on to investigate the performance of tool electrode manufactured by PM process.…”