Surface Finishing of Carbon-Carbon Composites Using Abrasive Flow Machining

Abstract

Carbon-carbon composites (C/Cs) are widely used in the high-technological applications because of their superior properties compared to the other traditional materials. But the surface finishing of these materials using both conventional and unconventional machining (e.g., abrasive flow machining, AFM) is difficult because of their nonhomogeneity, anisotropy, hardness and intrinsic brittleness. In order to study the feasibility of AFM, 3-D C/Cs were initially ground to a surface roughness value in the range of 0.7 ± 0.1 μm, and then finished using newly reported media containing styrene butadiene rubber as a carrier, silicon carbide (SiC) as abrasives and hydraulic oil as a processing oil. The effects of process parameters, such as abrasive mesh size, extrusion pressure, loading of processing oil and abrasive particles, and the number of cycles on the improvement in surface roughness of the C/C material were studied. The best surface finish was observed at an extrusion pressure of 6 MPa and 150 cycles using a media having 70wt% SiC abrasive particles of 220 mesh size and 12wt% processing oil. Further, the surface texture of the workpieces was studied by scanning electron microscope.

Keywords:

• Carbon-carbon
• abrasive flow machining
• silicon carbide
• styrene butadiene rubber

Acknowledgments

The authors acknowledge the financial support provided by Indian Space Research Organization, India; Aeronautics Research and Development Board, India; and India for carrying out this research work.