With the rising trend of miniaturization in modern industries, micro manufacturing processes have made a significant position in the manufacturing domain. Demands of high precision along with super finish of the final machined product have started rising. Grinding, being largely considered as a finishing operation, has large potential to cater to such requirements of micro manufacturing. However, stochastic nature of the grinding wheel topography results in a high degree of variation in the output responses especially in the case of microgrinding. With an aim to obtain a good and predictable surface finish in brittle materials, the current study aims at developing a surface generation model for wall grinding of hard and brittle materials using a microgrinding tool. Tool topographical features such as grit protrusion height, intergrit spacing, and grit distribution on the tool tip of a microgrinding pin have been calculated from the known mesh size of the grits used during tool manufacturing. Kinematic analysis of surface grinding has been extended to the case of wall grinding and each grit trajectory has been predicted. The kinematic analysis has been done by taking into consideration the effect of tool topographical features and the process parameters on the ground surface topography. Detailed analysis of the interaction of the grit trajectories is done to predict the final surface profile. The predicted surface roughness has been validated with the experimental results to provide an insight to the surface quality that can be produced for a given tool topography.

In the current study, electrochemical machining of Inconel 825, a nickel-based super alloy, was carried out using with tungsten as a tool electrode material and NaCl as electrolyte. The present investigation attaches particular emphasis on explaining mechanism of material removal of Ni-based super alloys in ECM process. The influence of various ECM parameters such as voltage (V), concentration (C) and tool feed (F) has been investigated on evolution of surface morphology of Inconel 825 after ECM. Different performance measures in ECM like material removal rate (MRR), surface roughness (SR) and radial overcut (ROC) have been measured. Grey relational analysis that uses grey relational grade as performance index has been adopted to simultaneously optmise multiple performance characteristics and determine optimal combination of ECM parameters. Moreover, principal component analysis is utilised to determine the weighting values corresponding to various output responses so that their relative importance can be adequately expressed. Optimal condition was found to be V=16V, C=45g/l and F= 0.3 mm/min. Confirmation test was further performed to authenticate the approach applied for determining the optimal conditions which resulted in MRR of Downloaded by [University of Western Ontario] at 12:20 08 February 20152 20.867 mm 3 /min, SR of 0.156 μm and ROC of 0.0697 mm which were superior to those corresponding to all previous experimental runs.

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