Experimental studies on graphene powder in dielectric for electrical discharge machining

• Main Author: Chong, Zhe Han.
• Other Authors: Yeo Swee Hock
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/53634
• Institution: Nanyang Technological University

Powder Mixed electrical discharged machining had been researched and were found to have significant improvements. When the optimum amount of powder were introduced into dielectric, improvements like higher materials removal rate, lower surface roughness and tool wear rate can be obtained. This project explored the changes that graphene powder in dielectric EDM had on the machined surface. Comparative analyses were made between conventional EDM and graphene powder mixed EDM to identify the differences. Work piece materials of AISI 1045, H13, Inconel 718 and Pure Titanium were considered due to high binding energy with graphene. Experimental results showed that adding graphene powder in dielectric caused a significant increase in discharged power; AISI 1045 experienced 2.5 times increment in discharged power when graphene powder was introduced. The increased in discharged power is the result of `bridging effect’ by the powder particles that cause short circuiting and arching. It is also observed that the electrical resistivity of materials were inversely proportional to the discharged voltage with the exception of Inconel 718. Subsequently, surfaces produced by graphene powder mixed EDM exhibited an slight increment in carbon content; all materials exhibited an increase of less than 5 percent. On the other hand, the surface hardness of graphene powder mixed EDM is significantly lower than conventional EDM. All materials experienced a reduction of surface hardness when the discharge energy increases. Finally, both conventional and graphene powder mixed EDM have the same accretion thickness of 2μm. However from the EDM image, graphene powder mixed EDM seems to suggest a better surface finish.