Semi-empirical Modeling of Surface Roughness in Wire Electro-discharge Machining of Ceramic Particulate Reinforced Al Matrix Composites

Most of efforts to model WEDM process have been made in the past. Earlier studies have been undertaken on monolithic materials such as steels. However, very few studies have been undertaken to model this process in machining of metal matrix composites. Although, significant number of publications is available on modeling of WEDM in machining of MMCs, most of the models are empirical. Moreover, earlier studies failed to incorporate the effects of constituents (ceramic particles and metal matrix) on the process behavior. In view of this, the objective of this study was to develop model for surface finish (Ra) based on machining process parameters, material properties, volume fraction and average ceramic particle size. The volume fraction and size of the particulates not only alters the thermal and physical properties of the resulting composites but also affects the process behaviour and machined surface morphology separately. Therefore it was decided to include the size of particles and the volume fraction to develop a new model for surface finish, Ra. The findings of this study lead to greater insights about material removal during machining of these difficult to machine materials using WEDM. Predictions of this model have found to be in close agreement with experimental results. The results of nonlinear estimation show that the properties such as heat of fusion, coefficient of thermal expansion, thermal diffusivity and melting temperature are most significant properties in machining of these composites. The role of ceramic particle has been highlighted with greater insight into the process and surface characteristics of these materials.