Investigations on the toolpath strategies for CNC magnetorheological fluid assisted finishing (MFAF) process

A computer numerical controlled (CNC) magnetorheological fluid assisted finishing (MFAF) process can super-finish the metallic surfaces of objects without any human intervention. In such a system, a rotating MFAF tool follows a path inside the region to be processed. An appropriate toolpath strategy can significantly reduce surface roughness. This work investigates different toolpath strategies such as Zig-Zag, Hilbert, Peano, Spiral, and Trochoidal for the MFAF process. A comparison is made among these toolpaths on the magnitude of the final surface roughness (R-a) and its variation on the finished profile on a similar domain with the same process parameters. In Zig-Zag and Spiral toolpaths, unidirectional crests are produced as polishing tool passed over the surface; this undesired orientation generates a non-uniform finished surface. The fractal curves such as Hilbert and Peano consist of significantly high numbers of sharp turns, making them unsuitable for the process. The Trochoidal toolpath, conventionally used for high-speed milling operation, is the most suitable toolpath for the MFAF process. The investigation shows that the Trochoidal toolpath reduces a mild steel plate's surface roughness (R-a) from 379 nm to 1.06 nm.

Automated summary

A computer numerical controlled magnetorheological fluid assisted finishing process can super-finish metallic surfaces without human intervention. This study investigates different toolpath strategies and finds that the Trochoidal toolpath is the most suitable for the process.