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The past few decades have witnessed significant advancements in turning processes, cutting tools and coolant/lubricant chemistry. These developments have enhanced the machining capabilities of hard materials when machining at higher cutting conditions. Turning, being characterized by the development of high temperatures at the cutting zone, is critical with respect to the tool life and surface finish apart from other machining results like the forces generated. This phenomenon of heat generation at the cutting zone plays a negative role during turning operations due to their peculiar characteristics such as poor thermal conductivity, high strength at elevated temperature, resistance to wear and chemical degradation. Cutting fluids and solid lubricants are generally used to overcome the problem of heat generation at the cutting zone. The use of cutting fluids in the conventional way may not effectively control the heat generated in turning operation. Moreover, cutting fluids are a major source of pollution. With the advancement in technology, nano-level particulate solid lubricants are being used nowadays in machining operations, especially grinding and turning. The present work deals with the investigation of using nano-level particulate graphite powder as a solid lubricant and various tests were conducted by machining AISI 1040 steel using tungsten carbide inserts. The experiments were conducted by taking into account the parameters like feed rate ranging from 0.05 mm/rev to 0.125 mm/rev, cutting speed ranging from 51 m/min to 192.6 m/min and depth of cut from 0.25 mm to 1 mm. Four levels of each parameter are considered for experimentation. The results indicate that with the decrease in the nano-sized graphite powder, there is an increase of cutting forces – feed force, cutting force and thrust force. The temperatures at the tool–chip interface also increases with the decrease in the lubricant size. It is found that the surface roughness of the workpiece after machining deteriorated due to the size of the lubricant particle.

In order to improve the performance of the cutting tool, it is required to model the metal cutting process at the system level. To predict and enhance the cutting tool performance the primary requirement of the system is the efficiency of the model explaining the interactions at the tool chip interface. The predominating parameters which influence the development of the system are work piece material and machining variables or sometimes both. Further the development of low cost methodology to study the chip tool interactions with minimum amount of testing is of more importance. Major part of the work is emphasized on the investigation and characterization of various zones on the rake face of tungsten carbide inserts. Tests have been carried out by machining AISI 1040 steel using WC inserts with variable dry conditions examining the chip flow phenomenon on the rake face of considerable number of samples. Taguchi method is adopted for the design of experimental conditions. Results have shown an acceptable chip flow patterns and authors were able to quantify the wear zones on the rake face. The rake face is then characterized to represent all the possible cases of chip flow patterns, crater wear and chipping of the cutting edge. Side and end cutting edges are taken as datum lines for locating the wear zones. The quantification and locations of the wear zones might help the researchers and tool makers to concentrate more on the defined areas instead of the rake face in total.