Experimental investigation of laser-assisted grinding of ceramic materials

Abstract

The so-called advanced ceramics, or engineering ceramics, are different from the conventional ceramics because of their specialized properties and sophisticated manufacturing processes. Among other characteristics, this material has high values of thermal and wear resistances, hardness, chemical inertia, thermal stability and high stiffness-weight ratio. They are frequently used in high performance applications such as high precision electronic and optical devices. However, its usage in several other areas is limited by the difficulties found during machining, increasing the costs of processing. One of the main problems is the formation of surface and subsurface micro cracks during the machining process due to brittle fracture mechanism of material removal presented in the process - a typical behavior of ceramics. These defects have a great influence on the designed function of the component, reducing its strength and surface quality. Consequently, it is necessary to develop new machining techniques in other to improve the efficiency and the feasibility of the advanced ceramics processing. The objective of this work is to use a hybrid grinding approach that uses a laser irradiation prior to the grinding process to weaken the ceramic material by inducing thermal cracks in its surface. The cracks are generated because of the tensile stresses induced during laser heating/cooling steps. To evaluate the feasibility of the novel technique, experiments will be carried out on different ceramic materials to evaluate the effects of the laser beam and grinding parameters on process forces, grinding wheel wear, flexural strength and surface integrity of the ceramic material. (AU)