Papers by Author: S. Gowri

Abstract: Micro turning is a scaled down version of conventional turning process, but operating on the micro scale of machining parameters to produce micro components. This paper deals with CNC Micro turning of Inconel 600 alloy with titanium carbide coated tool. Two conflicting objectives, surface roughness and tool flank wear, are simultaneously optimized. Full factorial experiments were taken with several combinations of cutting speed, feed and depth of cut. In this report, a new optimization algorithm based on the law of gravitation and mass interactions, namely Gravitational Search Algorithm (GSA) is aimed to predict the optimal parameter conditions for controlling tool flank wear and better surface finish.

Abstract: Wire Electrical Discharge Machining is one of the important non-traditional machining processes, which is used for machining difficult to machine materials and intricate profiles. In this present study, machining is done using Wire-Cut EDM and experimentation is planned according to Taguchi’s design of experiments [2]. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, and pulse OFF time and Wire feed. Inconel 800 was selected as a work material and Brass wire of 0.25mm diameter as the tool to conduct the experiments. From experimental results, the surface roughness and Kerf Width was determined for each machining performance criteria. Grey Relational Analysis [1] is used for optimization of Surface Roughness and Kerf width.

Abstract: Micro turning is a process by which micro components can be produced. This paper deals with the CNC micro turning of Inconel 600 alloy with titanium nitride insert tool. Full factorial experiments were conducted to obtain tool Flank wear and Surface roughness (Ra) for different cutting conditions. Using the measured data, Grey Relational Analysis is used to predict the optimal parameter conditions for controlled tool flank wear and better surface finish.

Abstract: Coated abrasives are extensively used for manual operations such us cleaning, deburring, polishing, etc. With the trend towards increased production rates, demands on coated abrasive belts are becoming increasingly severe. . Experimental investigations are to be made to know the effects of the process parameters on the performance of the surface belt grinding process. It is necessary to investigate the effect of flexing along with other input process parameters on output. In the present work the Taguchi’s experimental design method is used for performing the belt grinding process on the stainless steel AISI 304 and optimizing the process parameters. Thus, this research aims at right choice of flexing and grinding parameters for the coated abrasive belts. The results were further analysed by Taguchi’s signal to noise ratio for finding the optimum process parameters.

Abstract: Micro WEDM is a versatile technique used to machine electrically conductive materials to make components for micro system technologies. This paper presents an attempt to develop an appropriate machining strategy for micro WEDM of titanium alloy using zinc coated copper wire of 70 µm diameter. Voltage, capacitance, feed, wire tension and wire speed were taken as input parameters. Surface finish is considered as the measure of process performance. Design of experiments was done using Taguchi L16 orthogonal array and optimization was carried out using Taguchi S/N ratio technique. The results obtained from the experiments were analyzed with ANOVA method to find the significance of each input factor on the surface quality. In addition ANN model was developed and trained.

Abstract: Miniature parts with high accuracy and precision are increasingly in demand for various industries. Microturning is a process for fabrication of such miniaturized parts with features that range from tens of micrometres to a few millimetres. In this present study commercially available Oxygen Free High Conductivity (OFHC) copper rods have been microturned using cermet inserts of 0.1mm nose radius. The effects of machining parameters on the surface generated have been discussed. Scanning electron microscope images of worn out inserts and machined surfaces are analysed to ascertain the wear mechanism and study the nature of the surface generated.

Abstract: Advanced structural ceramics have been increasingly used in automotive, aerospace, military, medical and other applications due to their high temperature strength, low density, thermal and chemical stability. However, the Grinding of advanced ceramics such as alumina is difficult due to its low fracture toughness and sensitivity to cracking, high hardness and brittleness. In this paper, surface integrity and material removal mechanisms of Alumina ceramics ground with SiC abrasive belts, have been investigated. The surface damage have been studied with scanning electron microscope (SEM). The significance of grinding parameters on the responses was evaluated using Signal to Noise ratios.This research links the surface roughness and surface damages to grinding parameters. The optimum levels for maximum material removal and surface roughness been discussed.

Abstract: In this work, an FPGA hardware based image processing algorithm for preprocessing the images and enhance the image quality has been developed. The captured images were processed using a FPGA chip to remove the noise and then using a neural network, the surface roughness of machined parts produced by the grinding process was estimated. To ensure the effectiveness of this approach the roughness values quantified using these image vision techniques were then compared with widely accepted standard mechanical stylus instrument values. Quantification of digital images for surface roughness was performed by extracting key image features using Fourier transform and the standard deviation of gray level intensity values. A VLSI chip belonging to the Xilinx family Spartan-IIE FPGA board was used for the hardware based filter implementation. The coding was done using the popular VHDL language with the algorithms developed so as to exploit the implicit parallel processing capability of the chip. Thus, in this work an exhaustive analysis was done with comparison studies wherever required to make sure that the present approach of estimating surface finish based on the computer vision processing of image is more accurate and could be implemented in real time on a chip.