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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Sumitra Sahoo ¹, P. K. Jain ¹

Affiliations
1 Department of Mechanical & Industrial Engineering, IIT, Roorkee, IN

Abstract

Electro chemical Honing (ECH) is one of the most potentially emerging unconventional machining processes. This is a hybrid machining process combining the capabilities of electro chemical machining (ECM) and conventional honing. Owing to its advantages of both the processes, ECH is capable of producing high surface finish, tolerance, controlled surface generation of cross-hatch lay pattern or completely stress free and correction of geometrical inaccuracies on cylindrical work pieces such as out-of roundness, cylindri city, axis distortion etc. with very high productivity as compared to conventional super finishing processes. Surface finish of the order of 0.05μm and tolerance within ±0.002 can be obtained. This is well within the category of super finishing. This paper presents a complete review of electrochemical honing of cylindrical parts including internal holes, internal and external surface of cylinders with the objective to highlight the capabilities of ECH process. The competence of ECH towards achieving super finishing is mainly focused.

Keywords

Electrochemical Honing, ECM, Internal Cylinder, Cylindrical Holes, Superfinishing.

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J. P. Misra ¹, P. K. Jain ¹, D. K. Dwivedi ¹, N. K. Mehta ¹

Affiliations
1 Dept of Mechanical and Industrial Engg., Indian Institute of Technology, Roorkee, IN

Abstract

From last few decades, the gear finishing processes draw the attention of researchers to improve the service performance of gears which is a very essential element in many crucial products for mankind namely automotive products, ships, wind-power systems, machine tools or general gear boxes. This paper presents the experimental investigation of bevel gear finishing using an abrasive bonded mitre gear in an indigenously designed and developed experimental setup. The experimentation has been carried out to evaluate the effect of finishing time and rotating speed of workpiece on improvement in surface quality of gear teeth profile and material removal rate (MRR) of the process. Surface quality of the finished gear has been also analysed and it was found that the process produces a smooth surface by reducing irregularities. Furthermore, future scopes of the process are also highlighted.

Keywords

Bevel Gear, Gear Finishing, Abrasives, Surface Integrity.

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J. P. Misra ¹, P. K. Jain ¹

Affiliations
1 Mechanical and Industrial Engg. Dept., Indian Institute of Technology, Roorkee, IN

Abstract

This paper presents the study of electrochemical honing process used for gear finishing. Electrochemical Honing (ECH) is used for finishing internal cylinders and gears, based on the combination of Electrochemical Machining (ECM) process having high material removal capability and controlled functional surface generating capability of conventional honing process in a single operation. The workpiece hardness is not a limiting factor for ECH process and as the material removal mostly occurs due to electrolytic dissolution; a nano level finish is achieved and hence, it can be used widely in automobile, avionics, petrochemical, power generation, and fluid power industries. This paper describes the process principle, parameters, capabilities, equipment details of ECH of gears and a comparative study of different gear finishing processes with some directions for future research with an objective to revive the interest of the global research community to further mature this process.

Keywords

ECM, Honing, ECH, Gear Finishing.

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Pragya Shandilya ¹, P. K. Jain ¹, N. K. Jain ²

Affiliations
1 Dept. of Mechanical and Industrial Engg., Indian Institute of Technology, Roorkee, IN
2 Dept. of Mechanical Engg., Indian Institute of Technology, Indore, IN

Abstract

Aluminum metal matrix composite (MMC) is a kind of difficult to machine material. In general it is inefficient if conventional methods are used to machine it, with worse surface quality and serious wear of the cutting tool. This paper reports experimental investigations of the effect of machining parameters namely servo voltage (SV), pulse-on time (T_ON), pulse-off time (T_OFF) and wire feed rate (WF) on average cutting speed during wire electrical discharge machining (WEDM) of SiC_p/6061 Al metal matrix composite. Response surface methodology (RSM) has been used to plan and analyze the experiments. Voltage, pulse-off time and wire feed rate were found to have significant effect on average cutting speed.

Keywords

MMC, WEDM, Average Cutting Speed, RSM.

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P. Jerripothu ¹, P. K. Jain ¹, N. K. Mehta ¹, J. P. Misra ¹

Affiliations
1 Mechanical & Indl Engg Dept, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, IN

Abstract

Gears are used to transmit power and/or motion from one shaft to another by means of gradual engagement of teeth. The running performance of gears greatly relies on the surface quality of gear teeth profile. This paper reports the effect of processing time during Pulse-Electrochemical Honing (PECH) which is a hybrid micro-finishing process combining the faster material removal capability of electrochemical machining and surface generating capability of honing with assistance of pulse power supply and reported as one of the most potential process for gear finishing. In the present study, the effect of processing time on surface profile parameters of gear teeth profile (i.e. R_a, R_z, and R_tm) has been investigated and analysed. Surface microtopography characteristics have also been studied using optical profilometer to evaluate the contribution of the process in improving the surface quality of gear teeth profile. The emphatic features of developed experimental setup have also been highlighted.

Keywords

Gears, Hybrid Machining, PECH, Surface Microtopography Characteristics.

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