Translucent material transfer based on single images

The electrical discharge machining (EDM) process is extensively used in the tool and die making industry for accurate machining of internal profiles in hardened materials. Although it is essentially a material removal process, efforts have been made in the recent past to use it as surface treatment method. This article investigates and compares the effect of material transfer from electrode bodies (copper, copper—chromium, and copper—tungsten) and tungsten powder suspended in the dielectric medium during die-sinking EDM of AISI H13 die steel. Results show a 76 per cent increase in micro-hardness by machining with a copper—tungsten electrode and a 111 per cent increase by machining with tungsten powder mixed in the dielectric. The copper—chromium electrode gives the best surface roughness (Ra) value of 2.67 μ m. Scanning electron microscopy and X-ray diffraction analysis of the machined surfaces show alloying of parent material with tungsten and tungsten carbide. Chemical composition of the machined surfaces was further checked on an optical emission spectrometer to verify the results. Besides a significant presence of tungsten, an increase in the percentage of carbon is also observed.

Download Full-text

Optimization and surface modification in electrical discharge machining of AA 6061/SiCp composite using Cu–W electrode

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/1464420715596544 ◽

2015 ◽

Vol 231 (3) ◽

pp. 332-348 ◽

Cited By ~ 4

Author(s):

Balbir Singh ◽

Jatinder Kumar ◽

Sudhir Kumar

Keyword(s):

Process Parameters ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Surface Characteristics ◽

Electrode Wear ◽

Material Transfer ◽

Machined Surface ◽

Recast Layer Thickness ◽

Pulse On Time ◽

Pulse Off Time

This paper presents the experimental investigation on the electro-discharge machining of aluminum alloy 6061 reinforced with SiC particles using sintered Cu–W electrode. Experiments have been designed as per central composite rotatable design, using response surface methodology. Machining characteristics such as material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR) have been investigated under the influence of four electrical process parameters; namely peak current, pulse on time, pulse off time, and gap voltage. The process parameters have been optimized to obtain optimal combination of MRR, EWR, and SR. Further, the influence of sintered Cu–W electrode on surface characteristics has been analyzed with scanning electron microscopy, energy dispersive spectroscopy, and Vicker microhardness tests. The results revealed that all the process parameters significantly affect MRR, EWR, and SR. The machined surface properties are modified as a result of material transfer from the electrode. The recast layer thickness is increased at higher setting of electrical parameters. The hardness across the machined surface is also increased by the use of sintered Cu–W electrode.

Download Full-text