Effect Of Carbon Additives And Surfactant On Electrical Discharge Machining (EDM) Of Reaction-Bonded Silicon Carbide (RB-SiC)

• Main Author: Abdul Razak, Muhammad Raziman
• Format: Thesis
• Language: English
• Published: 2017
• Subjects: T Technology (General); TJ Mechanical engineering and machinery
• Online Access: http://eprints.utem.edu.my/id/eprint/20562/; http://library1.utem.edu.my:8000/elmu/index.jsp?module=webopac-d&action=fullDisplayRetriever.jsp&szMaterialNo=0000106862

Reaction-bonded silicon carbide (RB-SiC) is an important material in the manufacturing industry due to its excellent material properties. However, due to its high hardness, there are difficulties in machining this material to a good surface finish and with a high level of accuracy. To overcome these problems during the machining of ceramic materials, electrical discharge machining (EDM) is employed. Thus, the primary aim of this research is to conduct a comparative study of EDM on this material using different types of surfactant, concentrations of surfactant and carbon additive. The dielectric fluid, kerosene was mixed with different surfactants, namely Span 20 and Span 80. In order to investigate the effects of the surfactants, different concentrations of surfactant, namely 0 wt.%, 0.4 wt.%, 0.6 wt.% and 0.8 wt.%, were used. Carbon nanofiber (CNF), carbon nano powder (CNP) and carbon powder (CP) were used as an additives in this experiment. These powders are different in terms of size and shape. The responses of the machining, such as the stability of mixtures, material removal rate (MRR), electrode wear ratio (EWR), surface roughness, spark gap and surface topography, were also investigated. The results show that the surfactant and additives added to the dielectric fluid not only improved MRR and spark gap, but also reduced EWR, especially for the surfactant Span 80. The addition of a surfactant can prevent the agglomeration of powders and cause the powders to disperse well within the dielectric fluid. Therefore, the electro discharge frequency is increased, leading to a higher MRR and spark gap. The optimum weight percentage of surfactant concentration for obtaining smoother surface was at 0.4 wt.%. In terms of additives, CNF showed significant changes for MRR and EWR compared to CNP and CP. For comparison, the combination of surfactant Span 80 with 0.6 wt.% concentration of surfactant and CNF as additive is more significant in improving the machining efficiency of RB-SiC using conventional EDM compared to other surfactants, concentrations and additive powders.