Experimental Investigation on Surface Roughness in Electrical Discharge Turning of Ti-6Al-4V Alloy

This study presents a novel EDM turning process specially designed and developed to generate precise cylindrical forms on hard and difficult-to-machine materials. For this purpose, a specially designed turning spindle is used. The spindle was mounted on a conventional die-sinking EDM machine to rotate the workpiece. Axially symmetric parts can be manufactured by feeding the shaped tool into the rotating workpiece. In this way an axisymmetric workpiece can be made with small tools at both macro and micro levels. Effects of machining parameters, such as the current, pulse-on time, rotational speed, flushing pressure, and duty factor, on the surface roughness of Ti-6Al-4V alloy in electrical discharge turning were investigated. Taguchi\u27s design of experiment technique was used. Analysis of variance and regression analysis were performed on experimental data. The signal-to-noise ratio analysis was employed to find the optimal condition

Optimization Of Material Removal Rate And Surface Roughness Using The Taguchi Method

A non-conventional hybrid machining method called electrical discharge turning (EDT) process is optimized in this research. The EDT process is a suitable method to produce small components with cylindrical geometries. This process is a type of hybrid electrical discharge machining (EDM), hence the material is removed by the action of electrical discharges between the tool electrode and the workpiece. It means materials of any hardness can be removed as long as the workpiece can conduct electricity. This makes the EDT process suitable for machining hard, difficult-to-machine materials. In this process linear geometry of a tool electrode reproducing the same geometry in the rotating workpiece cylindrically. In this study, a dressed copper block (8mm × 10mm × 50mm) serving as the forming tool electrode is fixed on the work table and rotary workpiece uses the rotational motion of 4th (C) axis of the machine. The Taguchi Robust Design method was used to determine the optimum machining performance namely the highest material removal rate (MRR) and the lowest surface roughness (SR) for EDT of High Speed Steel (HSS) 5%-Cobalt. Six control factors namely, Intensity, Pulse-on time, Pulse-off time, Voltage, Servo, and Spindle speed were considered. Based on the analysis of variance (ANOVA) all six factors were influential for MRR but for SR rotational speed did not show any influence. Intensity was the most significant factor for both response of MRR and SR. Signal to Noise (S/N) analysis was performed and optimum levels of the mentioned factors for highest MRR and the lowest SR was achieved based on the S/N ratios. Results of confirmation tests shown the improvement of MRR and SR in optimum condition were 9.17 and 6.54 dB respectively. Finally general linear regression models were derived for 95% confidence interval to predict the output response. The p-value for the used α-level of 0.05 concluded that at least one of the regression coefficients is significantly different from zero and the linear predictors are not sufficient to explain the variation

Modeling of micro tool fabrication process using wire electro discharge grinding

Ankara : The Department of Industrial Engineering and the Graduate School of Engineering and Science of Bilkent University, 2013.Thesis (Master's) -- Bilkent University, 2013.Includes bibliographical references leaves 73-78.Fabrication of micro tools made from tungsten carbide and polycrystalline diamond is a difficult and time consuming process. Quality of the tool directly affects the dimensional integrity of the fabricated micro products. In this thesis, fabrication of micro end mills using wire electro discharge grinding (WEDG) process, a variation of electro discharge machining process, is considered. The advantage of this process is that very small micro tools (less than 0.1 mm diameter) can be produced by eroding the tool material through electrical discharges. It is preffered over traditonal grinding process since no forces are transmitted to the tool body during fabrication. However, it takes a very long time to fabricate micro tools with this method. Therefore, it is important to understand the influence of process parameters on material erosion rate in order to be able to model the process. In this study, the relationship between process input parameters and process outputs (material erosion rate and surface roughness) is investigated using experiments. A parametric formulation which allows the estimation of tool fabrication time as a function of WEDG process parameters and given tool geometry has been developed. The developed model can be used in tool geometry design optimization studies.Ergür, Ali CanM.S

application of process parameters in planning and technological documentation cnc machine tools and cmms programming perspective

Abstract This article focuses on the role and application of process parameters in technological process planning (TPP) and technological documentation (TD). The challenges and complexity involved in computer numerical control (CNC) machine tools and coordinate measuring machines (CMMs) programming have been taken into consideration with reference to the TD. The article presents the use of different programming platforms and implementation of them in technological process planning. The subtractive manufacturing and related measurements that are required during the TPP and TD phase have been taken into consideration. The findings and suggestions enable planners to incorporate the existing programming platforms and tools in the TPP and TD

On-machine fabrication of PCD and WC micro end mills using micro electro discharge machining

Micro electro discharge machining (μ -EDM) process can be used to fabricate micro-milling tools of different geometries from tungsten carbide (WC) and polycrystalline diamond (PCD). The non-contact nature of EDM process makes micro tool fabrication a challenging task while offering the advantage of eliminating tool run out and clamping errors since micro tools fabricated on-machine. The tools are fabricated and used on the same spindle. In this study, a combination of block-EDM and wire electro discharge grinding (WEDG) techniques are used to fabricate micro end mills of different geometries. The influences of EDM process parameters on material erosion rate and surface roughness are examined. The performance of the fabricated micro-tools in ductile mode machining of fused silica has been investigated. It is found that micro end mills can be used to fabricate prototypes of microfluidics chips with acceptable quality. © 2014 Inderscience Enterprises Ltd