Ajay Batish

Estimating the effect of cutting parameters on surface finish and power consumption during high speed machining of AISI 1045 steel using Taguchi design and ANOVA

The present paper outlines an experimental study to investigate the effects of cutting parameters on finish and power consumption by employing Taguchi techniques. The high speed machining of AISI 1045 using coated carbide tools was investigated. A combined technique using orthogonal array and analysis of variance was employed to investigate the contribution and effects of cutting speed, feed rate and depth of cut on three surface roughness parameters and power consumption. The results showed a significant effect of cutting speed on the surface roughness and power consumption, while the other parameters did not substantially affect the responses. Thereafter, optimal cutting parameters were obtained.

On Surface Finish and Dimensional Accuracy of FDM Parts after Cold Vapor Treatment

Fused deposition modeling (FDM) process is an additive manufacturing technology where objects are manufactured in layers. In the present days, FDM is commercially used to build prototypes, functional components; however, these parts majorly suffer from poor surface quality and dimensional accuracy even for basic part geometries. In the present paper, first the effect of part deposition orientation on surface finish and dimensional accuracy of FDM parts are studied. The part selected for this study is designed in such a way that different primitive geometric features at different directions are present. The parts are built at different orientations (0°, 15°, 30°, 45°, 60°, 75°, 90°) using acrylonitrile butadiene styrene P430 material, and surface finish and dimensional accuracy are measured at different surfaces. Next, the FDM parts are postprocessed by cold vapor treatment of dimethylketone (acetone) and improvement in surface finish and change in dimensional accuracy are investigated. The results show that surface finish of the components is greatly improved by this vapor treatment process with minimal variations in part geometric accuracy after the treatment.

Study of Surface Properties in Particulate-Reinforced Metal Matrix Composites (MMCs) Using Powder-Mixed Electrical Discharge Machining (EDM)

This article investigates the surface modification of three different types of metal matrix composites (MMCs) 65vol%SiC/A356.2, 10vol%SiC-5vol%quartz/Al, and 30vol%SiC/A359 using powder-mixed electrical discharge machining (PMEDM) process. Microhardness and surface integrity were evaluated after each trial, and contributing process parameters were identified. It was found that microhardness increased primarily with increase in the density of reinforced particles in the matrix. Each workpiece was examined by X-ray diffraction (XRD) followed by scanning electron microscope (SEM) for surface integrity and material deposition. The results show the significant amount of metal transfer from the copper electrode as compared to graphite.

Study of Material Transfer Mechanism in Die Steels Using Powder Mixed Electric Discharge Machining

The present article investigates the effect of process parameters and mechanism of material deposition in powder mixed electric discharge machining (PMEDM) on surface properties of EN31, H11, and High Carbon High Chromium (HCHCr) die steel materials. Current, powder, and interaction between workpiece and electrode affected the microhardness significantly. Copper electrode was found best for EN31 and H11 die steel, whereas tungsten-copper electrode was better suited for HCHCr steel to achieve higher microhardness. Graphite powder was found to be more suitable compared to aluminum in improving the microhardness of all three materials. Selected samples were analyzed for X-ray diffraction (XRD) followed by microstructure analysis using a scanning electron microscope (SEM). The results showed significant material transfer from the electrode as well as powder, either in free form and/or in compound form. For maximizing the microhardness of the machined surface, optimum parametric settings were identified for the three materials.

Optimization of powder mixed electric discharge machining using dummy treated experimental design with analytic hierarchy process

The analytic hierarchy process (AHP) is widely used for the optimization of multiple responses from an experimental study. In the present study, a method to obtain more reliable global weight of different alternatives has been described for a powder-mixed electric discharge machining (EDM) process. Seven different process parameters were tested to study their effect on material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) using a specially designed Taguchi orthogonal array that could accommodate factors with varying number of levels. A three-level array L27 was modified to include two-level factors using dummy treatment. The process conditions that affected the three responses were identified and optimized together using AHP for high carbon high chromium (HCHCr), EN31 and hot die steel (HDS) workpiece material. Addition of powder in the dielectric improved the MRR as the electrical conductivity of powder reduces the dielectric insulating strength. Current, powder, and electrode material significantly affected the TWR. Kerosene as dielectric was observed to be a superior alternative than EDM oil. Graphite electrode worked best for HCHCr and EN31 and W–Cu electrode worked best for HDS as they globally optimize the three output variables. Also, Cu powder suspended in the dielectric resulted in an optimal solution for HCHCr and HDS and tungsten powder was seen to be a better choice for EN31 to globally optimize the responses. To overcome problems of poor finish at high current setting in EDM, the dielectric should be mixed with powder.

Metal Matrix Composites for Thermal Management: A Review

The most challenging objective in the electronic industries is to develop materials that demonstrate a tunable thermal property with todays microelectronic devices. The development of composite material with balanced thermal properties is highly appreciated and currently competing the traditional monolithic conductive material. However, the tailored thermal properties of the composite are significantly influenced by the composites constituents and their fabrication routes. This article presents a review of thermal properties of particulate as well as fiber-reinforced composite proportional to matrix microstructure, reinforcement architecture. The processing techniques used to fabricate composites have been addressed with an objective to achieve suitable thermal properties. The developments in the analytical and numerical simulation approach to predict the thermal conductivity and CTE of the developed composites have been critically reviewed. Lastly, future work needs attention is summarized.

A multipoint method for 5-axis machining of triangulated surface models

Abstract In this paper, we present a multipoint machining method for the 5-axis machining of triangulated surfaces with radiused end mills. The main idea is to drop the tool onto the surface to find an initial point of contact, and then rotate the tool while maintaining tangency with this initial point of contact until a second point of contact is found. The proposed procedure ensures a gouge-free position with two points of contact, allowing for a larger side step than a single point of contact method. This proof of concept paper presents the mathematical equations that must be solved to position the tool with two points of contacts on an STL surface. The paper further verifies the concept with simulations and presents experimental results to confirm the simulations.

Electric discharge machining of titanium and its alloys: a review

Titanium alloys have been widely used in many industries because of their high strength-to-weight ratio, resistance to corrosion and high temperature stability. However, inherent properties like low thermal conductivity and chemical reactivity at elevated temperatures pose a major problem in machining of these alloys. Electric discharge machining (EDM) is a non-traditional material removal process used for machining of high strength-high temperature resistant (HSTR) alloys, tough and fragile components of electrically conductive materials by using shaped tools in the presence of dielectric fluid. The present paper reviews the fundamental principles of EDM and work done with regard to effect of operating parameters on material removal rate (MRR), tool wear rate (TWR), surface roughness and surface improvements on titanium alloys work piece.

Mechanism of Material Deposition from Powder, Electrode and Dielectric for Surface Modification of H11 and H13 Die Steels in EDM Process

Surface modifications using the powder mixed electric discharge machining (PMEDM) process has gained a lot of research interest in recent few years. The present paper investigates the material transfer from the powder suspended in dielectric, electrode and dielectric material for enhancing the surface properties measured in terms of the microhardness of the machined surface for two kinds of die steels (H11 and H13). Four different powder materials aluminium, copper, graphite and tungsten were mixed with dielectric during machining with three different dielectric materials namely kerosene, EDM oil and refined mineral oil. Other process parameters were varied at suitable levels. Maximum increase in microhardness was observed with addition of tungsten powder and with tungsten-copper electrode even at lower current. Current significantly affected the transfer mechanism of material on the machined surface but was dwarfed by the very significant affect of powder which had the largest contribution. A relative comparison of microhardness between deposited and non-deposited regions showed an increase of 37% for H11 and 56% for H13 due to addition of powder. The photomicrographs of the machined surface also supported the material transfer from powder, electrode as well as dielectric forming compounds that suitably improve the surface properties of H11 and H13 die steel.

Material transfer mechanism during magnetic field–assisted electric discharge machining of AISI D2, D3 and H13 die steel

In this study, the surface modification and metallurgical analysis of three commonly used die steels were analyzed by microstructure and X-ray diffraction analysis after electric discharge machining and powder-mixed electric discharge machining. The effect of many process parameters was assessed for surface modification using magnetic field–assisted electric discharge machining process. It was observed that the microhardness of the machined surface increased by more than 200%. The analysis of machined surface confirmed material migration from added powder, dielectric and electrode. The magnetic field assisted in improving the material removal process. The strength of the magnetic field resulted in better expelling of material from workpiece and restricted the material migration from electrode especially in copper-based diamagnetic material. Deposition of tungsten and titanium carbide was observed, which increased the microhardness significantly. Titanium, tungsten and graphite powder aided favorably the increase in the microhardness.