The miniaturization of smart materials has become a new trend in the modern manufacturing industry due to its enormous application in the aerospace, biomedical, and automobile sectors. Nickel–titanium (NiTi)-based binary shape memory alloys (SMAs) are one of the smart materials with certain supreme features like shape memory effect, pseudo-elasticity, high ductility, strong corrosion-resistance, and elevated wear resistance. For this, several micro-machining processes have been developed to machine NiTi SMAs. This paper summarizes all of the conventional and non-conventional micro-machining processes employed to machine NiTi SMAs. In this review process, the surface integrity, dimensional accuracy of the machined surface, cutting force and tool wear analysis during conventional and non-conventional micro-machining of NiTi SMA are evaluated mostly with the aid of input process variables like cutting speed, depth of cut, width of cut, types of coolants, tool coating, discharge voltage, capacitance, laser fluence, pulse duration, scan speed, electrolysis concentration and gap voltage. The optimization of process parameters using different methods during conventional and non-conventional micro-machining of NiTi SMAs is also analyzed. The problems faced during conventional micro-machining of NiTi SMAs are overcome by non-conventional micro-machining processes as discussed. The present study aims to recognize potential developments in the improvement of the micro-machinability of NiTi SMAs.

Optimization of process parameters play an important role in machining operations. The present work deals with a multi-objective optimization method (Grey relational analysis) and Taguchi's orthogonal array (OA) technique in machining of AISI D2 steel using coated carbide tool in forced air-cooled condition considering it to be environment friendly. The process parameters considered are cutting speed, feed and depth of cut having three levels each. The performance parameters are surface roughness, flank wear and cutting force. Taguchi's orthogonal array L₉ is considered for the experimental design. Grey relational analysis technique is used for finding the optimal settings of the process parameters to obtain the value of surface roughness, flank wear and cutting force. The optimum grey relational grade has been found out to get the optimal setting of the experimental run. Then level wise grey relational grade has been found out from the experimental run for each parameter. The optimal settings based on the rank of the grey relational grade in the experimental run and level wise optimal settings of the parameters from the grey relational grade have been compared. The improvement of performance parameters is confirmed from the grey relational prediction analysis in comparison to optimal values in the experimental run.

The reinforcement of ceramic materials with electrically conductive particles increases the overall conductivity of the ceramic material. This allows the ceramic material to be more readily machined using wire electrical discharge machining process. The current work is an approach to identify the machinability of multi walled carbon nanotubes filled alumina composites in wire electrical discharge machining process. Alumina samples of 5 vol. % and 10 vol. % multi walled carbon nanotubes are machined and analysed for material removal rate and the surface characteristics. An increase in material removal rate is observed with increase in filler concentrations. At the same time, better surface roughness is observed. The surface characteristics of composite alumina are further compared with Monel 400 alloy. It has been observed that spalling action is the dominating material removal mechanism for alumina composites, while melting and evaporation is for the Monel 400 alloy.

Tool life is an important criterion in machining. So, to improve the tool life considering the flank wear, a novel technique of surface texturing is implemented on the flank face of the cutting tool. Two different types of textures viz. dot textures (DT) and groove textures (GT) perpendicular to the cutting edge are fabricated on the flank face of the ceramic and coated carbide tool using micro-electric discharge (µ-EDM) machining. Machining is then carried out on hardened H13 steel with both textured and non-textured (NT) tools. The machining performances are considered as surface roughness, flank wear and cutting temperature which are compared for both coated carbide and the ceramic tool for DT GT and NT. The surface roughness and flank wears during machining with DT are found lesscompared to GT and NT tools for both ceramic and coated carbide. Other hand, surface roughness and flank wears are found less in ceramic tool machining compared to coated carbide tool machining for textured as well as non-textured. The temperature generated at the tool-workpiece interface is higher for the ceramic tool machined surface reveals the formation of white layer which is found more for ceramic tool in terms of thickness and its micro-hardness. The surface produced during machining by textured and non-textured ceramic tool is more lustrous as compared to textured and non-textured coated carbide tool.