Study on minimum quantity lubrication (MQL) in grinding of carbon fiber-reinforced SiC matrix composites (CMCs)

Ceramic matrix composites (CMCs) are a new class of high-technology materials that can be utilized in hot-zone structures and as a lightweight replacement for metallic superalloys. CMCs offer low density, high hardness, and superior thermal and chemical resistance which make them highly attractive in a vast array of applications. Nevertheless, the high hardness, as well as the inhomogeneous structure of the CMCs, causes unstable processes and high tool wear when machining. In this research, MQL grinding, known as an economical and environmentally friendly grinding process, was accomplished and its efficiency was compared with conventional fluid and dry grinding. Along with obtaining of comprehensive results, the effects of main grinding parameters, such as cutting speed, feed speed, and depth of cut, on the grinding forces, specific grinding energy, wheel wear, surface roughness, and integrity were analyzed. The results showed that MQL grinding reduced the grinding forces and specific grinding energy. As a result, wheel wear was lowered and G-ratio was increased. In addition, the surface generated by MQL grinding was smoother than fluid grinding and significantly better than dry grinding.