Development of a micro-graphite impregnated grinding wheel

Abstract

This paper introduces a newly designed grinding wheel where micro-graphite particles are impregnated in an aluminum oxide matrix to form a grinding wheel to lubricate the grinding site; these are known as graphite-impregnated grinding wheels. The graphite particles were heat-treated under a layer of hydrogen ions at a temperature of about 500°C for 30min to disperse them uniformly in the aluminum oxide matrix. In this study, grinding wheels with five different graphite contents (0.1, 0.5, 1, 3, and 5wt%) were investigated. Different aspects of the grinding performance (e.g., surface roughness, morphology, wheel wear ratio, grinding temperature, and grinding forces) using these grinding wheels under two different coolant strategies (dry and minimum quantity lubrication with pure water) were compared with the corresponding values for a conventional grinding wheel. The experimental results indicate that using graphite-impregnated grinding wheels considerably improves the grinding process performance compared to using a conventional grinding wheel. A graphite content of below 0.5wt% is recommended because this provides not only better surface roughness and topography, and lower grinding temperature and force but also less grinding wheel consumption; hence, the wheel life was extended. In summary, combining graphite-impregnated grinding wheels with minimum-quantity lubrication technology has the potential to effectively eliminate the use of any oils or toxic organic lubricants in the grinding process.