An Experimental Analysis on the Role of Reinforcement on the Grindability of Metal Matrix Composites

Metal matrix composites are attractive materials in various fields of industrial applications because of their high specific strength, high wear resistance and good damping characteristics. One of the main problems arising when machining metal matrix composites is the low machinability due to abrasion of cutting tools by the reinforcement and poor quality of the surface finishing. Among traditional machining, grinding operation is playing an important role both for finish and heavy-duty operations. In this work the influence of shape, orientation and content of the reinforcement on the grindability of metal matrix composites is analysed by means of experimental tests carried out with a grinding wheel made by conventional abrasive. Investigations deal with grinding force and degradation of the grinding wheel surface, acquired during the machining process, and workpiece ground surface roughness, assessed off-line by means of a mechanical profilometer. The effects of workpiece material composition on grinding wheel wear and workpiece ground surface quality are described considering some grindability indices. Workpiece ground surface and chip morphology are analysed by scanning electron microscope.