Manufacturing Technology Today

H. Singh ¹, P. K. Jain ¹

Affiliations
1 Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee, IN

Abstract

The aim of the study is to investigate the micro-finish and flatness of the flat functional surfaces made of stainless steel (SS321) using a newly developed electrochemical honing (ECH) machine. ECH is a prominent hybrid machining process (HMP), which is widely used for precision finishing of intricate shapes and hard materials with an efficient and effective manner. In the present work, flat work surface is processed through ECH and pressing time dependent behavior of ECH has been studied. The results show that the ECH of SS321 surfaces gives a glazed appearance and produce an average surface roughness (R_a) of 0.84 μm, and flatness in the range of 5-12 μm with a processing time of 360 seconds. The analysis of finished surface through 3D optical profilometry images has shown improvement in the surface integrity of the workpiece. The microscopic analysis showed that the ECH processed surface is free of burr and scratches.

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H. Singh ¹, P. K. Jain ¹

Affiliations
1 Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee - 247 667, IN

Abstract

Electrochemical Honing (ECH) is a process of precision finishing of functional surfaces with the use of the electrical and mechanical energy. It is reported that the 90 percent of the material is removed by electrochemical machining (ECM) process and remaining 10 percent by mechanical scrubbing, which shows the electrical energy is the main constituent in the ECH process. Basically, electrical energy is combined with chemical to form an etching reaction to remove material from the workpiece surface. The electrolyte is pumped through the gap between the tool (cathode) and the workpiece (anode) while a continuous DC current is passed through the cell at a low voltage, so as to dissolve metal from the workpiece. Electrolytes are substances that become ions in solution and acquire the capacity to conduct electricity. The electrolyte has three main functions in the electrochemical machining (ECM) zone. It carries the current between the tool and the work piece, it removes the product of the reaction from the cutting region, and it removes the heat produced by the current flow in the operation. Electrolytes must have high conductivity, low toxicity and corrosivity, and chemical and electrochemical stability. The rate of material removal in ECM is governed by Faraday's laws and is function of current density. Primary variables that affect the current density and MRR are voltage, feed rate, electrolyte conductivity, electrolyte concentration/composition, electrolyte flow rate and material of the work piece. Therefore, electrolyte must be selected carefully for better outcomes.

Keywords

ECH, Electrolyte Composition, Electrolyte Concentration, EN52, Ti6Al4V, Surface Finish.

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H. Singh ¹, P. K. Jain ¹

Affiliations
1 Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee - 247667, IN

Abstract

Surface finishing of bevel gears is an main requirement in various machining shop floors. Variants of electrochemical honing (ECH) could be probable solutions for finishing such complex geometrical parts. This paper presents a comparative analysis of classical ECH, pulse-assisted ECH (PECH) and ultrasonic vibration assisted (UVECH) for tooth flank surface quality enhancement of bevel gears made of EN8 steel. The developed setups and the process has been compared with suitable illustrations. The tooth flank finish was analysed in terms of improvement in surface roughness, morphology of the finished surface and processing time. It was found that the UVECH finished gear exhibited better surface quality and lower processing time as compared to ECH and PECH finished gears. The PECH finished surface also gives better surface quality as compared with ECH, but the use of pulse-on and pulse-off time combination in PECH increases the time required to achieve the desired quality.

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