Microscopic investigation on micro electric discharge milling of AA6063-SiC composites

Abstract

Metal matrix composites (MMC) have found applications in places where the utilization of conventional materials is limited. This also includes areas of micro- and meso-applications. However, micromachining of metal matrix composites by conventional methods poses difficulties due to the heterogeneous nature of the material and the presence of hard reinforcement particles. Micro-ED milling is a versatile micromachining process used to machine hard engineering materials. It employs a simple cylindrical cross-section tool, which is rotated and fed in predefined paths to generate intricate 3D features with good dimensional accuracy and surface finish. In order to study the machining performance of micro-ED milling process on metal matrix composites, micro-ED milling of AA6063-4 wt.% SiC composite fabricated by ultrasonic-assisted stir casting was carried out. The tool feed rate and tool rotation speed are important parameters as they aid in debris evacuation and influence material removal. So, the effect of tool feed rates, tool rotation speeds and discharge energies on the surface morphology and surface roughness of the machined channels were studied. The surface roughness parameters, namely Sa and Sq, were considered for the study. The least surface roughness, Sa and Sq, was observed at 2 µm/s for all the investigated discharge energies.

Keywords:

• Metal matrix composites
• micro electric discharge milling
• microchannel
• micro-EDM
• surface morphology
• surface roughness

Acknowledgements

The authors are thankful to the Central Facility for Materials and Manufacturing Engineering (CFMM) at IIT Palakkad for the support received in using the micromachining facility. The authors would also like to thank the Central Instrumentation Facility (CIF) at IIT Palakkad for the extended support in the usage of characterization facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).