CUTTING FORCES AND SURFACE ROUGHNESS IN MACHINING Al/SiCp COMPOSITES OF VARYING COMPOSITION

Abstract

Knowing that the machined surface roughness of Al/SiCp composites is linked to its performance, this paper presents an elaborative experimentation using Taguchi methods on four composites to analyze the effects of size (15m and 65m) and volume fraction (20% and 30%) of reinforcements in the composites on machining forces and machined surface roughness. The independent variables in the experiment were: tool nose radius, cutting edge geometry, feed rate, cutting speed and depth of cut. The results show that, of the three machining force components, only radial force shows significant dependence on composition of composites. The machined surface roughness was found to be more sensitive to a change in size than to volume fraction of reinforcement in composites. However, all the independent variables, except the cutting speed, cause a statistically significant effect on the machined surface roughness for all composites. An analytical model giving a correlation between the machined surface roughness and the ratio of cutting forces [image omitted] was formulated based on the geometry of work-tool contact. The predicted surface roughness using the model was found to agree well with the experimental values, especially when the tool nose radius is less than the depth of cut.