Raviraj Shetty

Taguchi’s Technique in Machining of Metal Matrix Composites

This paper presents the study on Taguchis optimization methodology, which is applied to optimize cutting parameters in turning of age hardened Al6061-15% vol. SiC 25 µm particle size metal matrix composites with Cubic boron nitride inserts (CBN) KB-90 grade using steam as cutting fluid. Analysis of variance (ANOVA) is used to study the effect of process parameters on the machining process. This procedure eliminates the need for repeated experiments, time and conserves the material by the conventional procedure. The turning parameters evaluated are speed, feed, depth of cut, nozzle diameter and steam pressure. A series of experiments are conducted using PSG A141 lathe (2.2 KW) to relate the cutting parameters on surface roughness, tool wear, cutting force, feed force, and thrust force. The measured results were collected and analyzed with the help of the commercial software package MINITAB15. As well, an orthogonal array, signal-to-noise ratio is employed to analyze the influence of these parameters. The method could be useful in predicting surface roughness, tool wear, cutting force, feed force and thrust force as a function of cutting parameters. From the analysis using Taguchis method, results indicate that among the all-significant parameters, steam pressure is the most significant parameter.

Selection Of Optimal Process Parameters In Ball Burnishing Of Titanium Alloy

The current study deals with the analysis and optimization of the ball burnishing process of titanium alloy (Ti-6Al-4V). The Taguchi method was employed to determine the best combination of ball burnishing process parameters—such as burnishing speed, burnishing feed, burnishing force and number of passes—to minimize surface roughness and maximize hardness. The dry burnishing experiments were planned as per L9 orthogonal array (OA,) and signal-to-noise (S/N) ratio was applied to measure the proposed performance characteristics. Analysis of means (ANOM) and analysis of variance (ANOVA) were carried out to evaluate the optimal levels and to obtain the level of importance of the burnishing parameters, respectively. Validation tests with optimal levels of parameters were performed to illustrate the effectiveness of Taguchi optimization. The optimization results revealed that burnishing feed and burnishing force are the significant parameters for minimizing the surface roughness, whereas number of passes and burnishing force play important roles in maximizing the hardness.

Experimental and Finite Element Analysis on Chip Formation Mechanism in Machining of Elastomers

Computer simulation of metal cutting processes using the Finite Element Analysis (FEA) method are routinely practiced in todays industry. It is known from the theory of metal cutting that an examination of machined chips provides the cheapest and the most effective way of understanding the machining characteristics of a material. This paper discusses experimental work and finite element analysis to investigate the mechanism of chip formation during machining of Elastomer. Focus of this study is on understanding the influence of different cutting parameters on chip formation mechanism. From the experimental tests, it has been concluded that the morphology of rubber chips can be categorized into continuous ribbon-like chips with a smooth machined surface, segmented chips with a rough machined surface, and discontinuous chips with an even worse surface finish. Continuous ribbon-like chips are associated with a smooth surface finish, which occurs with large rake angle tools. Further from Finite Element Analysis it was observed that at lower rake angle, discontinuous chips are formed and Continuous ribbon-like chip occurs with large rake angle.

A Pressured Steam Jet Approach to Tool Wear Minimization in Cutting of Metal Matrix Composites

Metal matrix composites (MMCs) have been found to possess tremendous prospective engineering applications that require materials offering a combination of lightweight with considerably enhanced mechanical and physical properties. However, the applications of MMCs are limited by their poor machinability which is a result of their highly abrasive nature that causes excessive wear to the cutting tools. In this study, an investigation into the mechanism of the tool wear in cutting of MMCs is carried out. It is found that during cutting of an MMC, the tool cutting edge will impact on the reinforcement particles. The impacted particles will then either be dislodged from the matrix, doing no harm to the tool, or be embedded into the matrix, ploughing on the tool flank and causing excessive tool flank wear. According to this tool wear mechanism, a pressured steam jet approach is developed for the minimization of the tool wear by preventing the impacted reinforcement particles from being embedded in the workpiece matrix. Experimental tests for cutting of SiC–aluminum MMC using cubic boron nitride (KB-90) and polycrystalline diamond (KP-300) tool inserts with the aid of the pressured steam jet are conducted. The results show that from full factorial design of experiments the effect of the pressured steam jet plays a significant role on the tool wear followed by tool inserts and depth of cut. The working mechanism of the pressured steam jet method and the experimental testing results are discussed in detail.