Nano-finishing of a material surface is one of the most required properties in industry. There is high need of nano-finishing of diamagnetic materials such as copper and its alloys in electronic industries and electrode of electric discharge machining. Some industries like laser, aerospace, dentistry and metal optics etc. widely use highly finished copper mirrors. As copper is soft and chemically reactive material, its surface finishing at nano level is a difficult tasked. To fulfill this need, a new magnetorheological technique for precise surface finishing of diamagnetic materials has been conceptualized. Two cylindrical permanent magnets along with magnetorheological polishing fluid have been used to finish the diamagnetic copper alloy workpiece. The cylindrical permanent magnets tool with magnetorheological polishing fluid at its tip surface is rotated over the copper alloy workpiece surface and performs finishing by the stiffened magnetorheological polishing fluid. The permanent magnets finishing tool along with magnetorheological polishing fluid at its tip surface and diamagnetic copper workpiece have been modeled as well as simulated in Maxwell Ansoft V13 (student version) software. Distribution of magnetic flux density in the working gap is obtained and analyzed. Experiments are performed on the copper alloy workpiece and least Ra value of 28.8 nm is achieved in finishing time of 7.5 min from its initial value of 273.6 nm. Surface characteristics of both polished and unpolished workpiece are analyzed with the scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results obtained from finite element analysis and experimentation assures that the new design of magnetorheological finishing tool using permanent magnets is capable to nano-finish of diamagnetic materials such as copper alloy etc.

Magnetorheological nano-finishing of diamagnetic material using permanent magnets tool

The need of fine finishing of gears with high shape accuracy increases in various industrial, military and scientific instruments applications for enhancing the working performance, power transmission capability, service life, reliability as well as decreasing noise and vibrations at high speed. The surface asperities, dimensional inaccuracy, rough surface and shape inaccuracy of a gear tooth profile occur because of the high speed of material removal mechanism which leads to undesirable effect such as noise and vibration in the gearbox. Therefore, utilizing the conventional tool for finishing of gears at high material removal rates may increase inaccuracy in gear teeth profile shape due to the transverse grinding lines, burns, fine cracks, uneven stress, and thermal distortion. This paper reports on a novel design of a magnetorheological gear profile finishing (MRGPF) tool and its performance analysis to finish the gear teeth profile with more precisely and accurately. The MRGPF tool is made likely similar to the gear grinding profile wheel tool. To analyze the uniform finishing at the gear tooth profile, the magnetostatic finite element analysis (FEA) is performed to predict the uniform magnetic flux density at the proposed tool surface using Maxwell Ansoft. On the basis of the result obtained of magnetic flux density distribution on its finishing surface, the MRGPF tool is designed and fabricated. Further, the experiments are performed to examine the finishing performance of the newly designed tool on the EN-24 steel spur gear teeth profile. The results attest the significant improvement in finishing of gear teeth profile surface with high shape accuracy (DIN standard). This may result in improvement in scuffing performance, reducing noise and vibrations at high speed, reducing wear rate on gear teeth profile and also provides lower friction and temperature during its functional operation.

A novel magnetorheological gear profile finishing with high shape accuracy

Analysis of surface finishing mechanism in a newly developed rotational magnetorheological honing process for its productivity improvement

Magnetically assisted abrasive finishing (MAAF) processes are the precision material removal processes that have been applied to a large variety of materials from brittle to ductile and from magnetic to non magnetic. The MAAF process relies on a unique “smart fluid”, known as Magnetorheological (MR) fluid. MR fluids are suspensions of micron sized magnetizable particles such as carbonyl iron, dispersed in a non-magnetic carrier medium like silicone oil, mineral oil or water. The MAAF processes overcome the limitation of abrasive flow machining by deterministically control the abrading forces by applying magnetic field around the workpiece. MAAF process is divided into two parts; one is magnetorheological finishing (MRF) and another is magnetorheological abrasive flow finishing (MRAFF). The MRAFF process gives better results as compared to results of MRF because it has additional reciprocating motion of MR fluid. In this article the attempt has been made to review various technical papers related to MRF and MRAFF. The experimental setups, process parameters, MR fluid, modeling & optimization and applications are discussed in this paper. This review article will be useful to academicians, researchers and practitioners as it comprises significant knowledge pertaining to MAAF.

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A review on magnetically assisted abrasive finishing and their critical process parameters

Ultra-high molecular weight polyethylene (UHMWPE) is a highly used polymer in the medical field due to its properties such as good mechanical strength, high hardness, good chemical resistance, and ...

Magnetorheological finishing of UHMWPE acetabular cup surface and its performance analysis

Modeling and simulation of surface roughness in magnetorheological fluid based honing process

In the current scenario, the advanced industries are using highly sophisticated types of machinery. These types of machinery use numerous cylindrical components made with superior materials and tec...

Theoretical and experimental investigations on nano-finishing of internal cylindrical surfaces with a newly developed rotational magnetorheological honing process:

Permanent mould dies are used for various plastic injection moulding products. Most of the mould cavity is blind and henceforth difficult to finish. In this study, a novel magnetorheological fluid-based finishing process using permanent magnet tools has been developed for nano-finishing of cylindrical blind hole surfaces. Tools to finish the internal and flat-bottomed surfaces of the cylindrical blind hole are developed. The finishing performance of both tools is evaluated for finishing ferromagnetic material used in dies. The material of the die is P20 tool steel having 41 HRC hardness. Response surface methodology using a central composite design technique has been utilized for the plan of experiments and analysis of significant process parameters on the percentage change in surface roughness using newly developed tools. During finishing the internal cylindrical blind hole surface, the process parameters like rotational speed, reciprocation speed and abrasive mesh size are found to be significant. However, during flat-bottomed surface finishing of cylindrical blind hole workpiece, rotational speed, abrasive mesh size and abrasives volume percentage are found to process significant parameters. Experimentation at optimized parameters results in the final surface finish of 83 nm on internal cylindrical surface and 93 nm on the flat-bottomed surface of cylindrical blind hole workpiece.

Experimental analysis of magnetorheological finishing of blind hole surfaces using permanent magnet designed tools

The cylindrical mold is an essential part used in industries for the manufacturing of various cylindrical products such as beverages canes, domestics appliances, glass beakers, and polyvinyl chloride pipes. These products require features in its surfaces such as defect-free surfaces with high-quality, stable dimensions, the high extent of cylindricity, and functional transparency in glass material products. To acquire such features in the cylindrical products, the rotary magnetorheological honing (R-MRH) process is developed. In this work, the response surface methodology technique is employed for optimizing the process parameters for internal surface finishing of the cast-iron (CI) cylindrical workpieces. With the optimized process parameters, the experiments are performed to find out the effectiveness of the present finishing process for CI cylindrical molds. On the final MR-finished surface after 40 min of finishing, the roughness parameters (Ra, Rz, and Rq) get reduced to 0.05 µm, 0.4 µm, and 0.07 µm from the respective initial values of 0.420 µm, 2.4 µm, and 0.52 µm. The waviness parameters (Wa, Wz, and Wq) achieved on the final finished surface are 0.04 µm, 0.20 µm, and 0.06 µm from the initial values of 0.17 µm, 0.90 µm, and 0.22 µm, respectively. Also, the circularity (C) on the MR-finished cylindrical surface is improved to 0.0437 from the initial circularity value of 0.1207. The significant changes in Ra, Wa, and C values as well as visuals of scanning electron microscopy images reveal a better sense of functionality improvement of the cast-iron cylindrical molds.

Sunil Kumar Paswan

Papers

Modeling and simulation of surface roughness in magnetorheological fluid based honing process

Analysis of surface finishing mechanism in a newly developed rotational magnetorheological honing process for its productivity improvement

Theoretical and experimental investigations on nano-finishing of internal cylindrical surfaces with a newly developed rotational magnetorheological honing process:

Experimental analysis of magnetorheological finishing of blind hole surfaces using permanent magnet designed tools

Investigation of Optimized Parameters for Magnetorheological Finishing the Internal Surface of the Cast-Iron Cylindrical Molds