Surface texture improvement of magnetic and non magnetic materials using magnetic abrasive finishing process

Abstract

The present study focused on surface texture characteristics of magnetic material, Mild steel (MS) as well as nonmagnetic material, Aluminum 2024 (Al 2024) alloy with the application of a laboratory-developed magnetic abrasive finishing (MAF) process. MAF is one of the unconventional finishing processes to attain a satisfactory finishing level up to nanoscale. In MAF, the surface finish is controlled by a flexible magnetic abrasive brush (FMAB) which has a combination of abrasives (Al2O3, SiC, etc.) and magnetic particles (iron powder). The experiments were planned using (L27) full factorial design, different levels of weight percentage of abrasives (20–30%), speed of the electromagnet (180–2100rpm), and electromagnet supply voltage (30–50 V) were varied to enhance the surface responses. The responses considered were % improvements of change in the surface finish (%ΔRa), change in average peak to valley height (%ΔRz), change in total profile height (%ΔRt), and change in mean square root surface finish (%ΔRq). Analysis of variances (ANOVA) was evaluated and discussed. It is observed that the speed of the electromagnet and voltage are the most influencing variable parameters that most impacted on the responses. Surface roughness was measured before and after the MAF processing of MS and Al 2024 using a Suftronic S-100 surface roughness tester. The obtained surface morphology was examined by Scanning Electron Microscopy (SEM). It was observed that MS has %ΔRa = 83, %ΔRz = 65, %ΔRt = 65.5 and %ΔRq = 72.6 while Al 2024 has %ΔRa = 65, %ΔRz =50, %ΔRt = 51 and %ΔRq = 55 with noticeable surface texture improvement compared to the initial surface roughness obtained using surface grinding process.