Toward Magnetorheological Finishing of Magnetic Materials

2007 ◽  
Vol 129 (5) ◽  
pp. 961-964 ◽  
Author(s):  
Shai N. Shafrir ◽  
John C. Lambropoulos ◽  
Stephen D. Jacobs
Keyword(s):  
Magnetic Material ◽  
Surface Roughness ◽  
Magnetic Materials ◽  
Material Removal ◽  
Subsurface Damage ◽  
Magnetorheological Finishing ◽  
Optical Glasses ◽  
Material Surfaces ◽  
Finishing Process ◽  
Deformed Layer

Magnetorheological finishing (MRF) is a precision optical finishing process traditionally limited to processing only nonmagnetic materials, e.g., optical glasses, ceramics, polymers, and metals. Here we demonstrate that MRF can be used for material removal from magnetic material surfaces. Our approach is to place an MRF spot on machined surfaces of magnetic WC-Co materials. The resulting surface roughness is comparable to that produced on nonmagnetic materials. This spotting technique may be used to evaluate the depth of subsurface damage, or deformed layer, induced by earlier manufacturing steps, such as grinding and lapping.

Experimental investigation into polishing of monocrystalline silicon wafer using double-disc chemical assisted magnetorheological finishing process

2021 ◽  
pp. 095440622098384
Author(s):  
Mayank Srivastava ◽  
Pulak M Pandey
Keyword(s):  
Surface Roughness ◽  
Silicon Wafer ◽  
Flow Rate ◽  
Silicon Wafers ◽  
Monocrystalline Silicon ◽  
Slurry Flow ◽  
Magnetorheological Finishing ◽  
Finishing Process ◽  
Process Factors ◽  
Slurry Flow Rate

In the present work, a novel hybrid finishing process that combines the two preferred methods in industries, namely, chemical-mechanical polishing (CMP) and magneto-rheological finishing (MRF), has been used to polish monocrystalline silicon wafers. The experiments were carried out on an indigenously developed double-disc chemical assisted magnetorheological finishing (DDCAMRF) experimental setup. The central composite design (CCD) was used to plan the experiments in order to estimate the effect of various process factors, namely polishing speed, slurry flow rate, percentage CIP concentration, and working gap on the surface roughness ([Formula: see text]) by DDCAMRF process. The analysis of variance was carried out to determine and analyze the contribution of significant factors affecting the surface roughness of polished silicon wafer. The statistical investigation revealed that percentage CIP concentration with a contribution of 30.6% has the maximum influence on the process performance followed by working gap (21.4%), slurry flow rate (14.4%), and polishing speed (1.65%). The surface roughness of polished silicon wafers was measured by the 3 D optical profilometer. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were carried out to understand the surface morphology of polished silicon wafer. It was found that the surface roughness of silicon wafer improved with the increase in polishing speed and slurry flow rate, whereas it was deteriorated with the increase in percentage CIP concentration and working gap.

Preliminary Results on Finishing of WC-Co Coating by Magnetorheological Finishing Process

2019 ◽  
Author(s):  
Gourhari Ghosh ◽  
Ajay Sidpara ◽  
P. P. Bandyopadhyay
Keyword(s):  
Surface Roughness ◽  
Ground Surface ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Magnetorheological Finishing ◽  
Machining Time ◽  
Mr Fluid ◽  
Mechanical Abrasion ◽  
Deformed Layer ◽  
End Use

Abstract Thermal spray coating has the ability to enhance the lifetime of engineering components by reinforcing the surface properties. The surface roughness of the as-sprayed coatings needs to be suitably finished for its end use. The nanofinished WC-Co coatings are widely used in aerospace and automobile industries. In this present investigation, surface grinding followed by the magnetorheological finishing (MRF) processes is employed for finishing of WC-Co coating. Boron carbide (B4C) powder is used as the abrasive particles in the MRF process. MRF spot finishing technique is performed on the ground coating. The plastically deformed layer from the ground surface is removed completely by the gentle mechanical abrasion of MR fluid ribbon. The surface roughness and volume of material removed are measured over the finishing time. It is perceived that the surface roughness of the finishing spot is increased after a threshold machining time. This is attributed to the aging of MR fluid and the mechanical abrasion of wear debris. The experiment is also performed with the assistance of Murakami’s reagent to perform etching and finishing, simultaneously. A comparatively higher finishing rate is observed in this case.

Magnetorheological finishing of silicon for nanometric surface generation: An experimental and simulation study

2018 ◽  
Vol 29 (11) ◽  
pp. 2456-2464 ◽  
Author(s):  
Neha Khatri ◽  
Suman Tewary ◽  
Xavier J Manoj ◽  
Harry Garg ◽  
Vinod Karar
Keyword(s):  
Molecular Dynamics ◽  
Surface Roughness ◽  
Surface Quality ◽  
Surface Finish ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Surface Generation ◽  
Magnetorheological Finishing ◽  
X Ray ◽  
Finishing Process

Silicon mirrors are essential for guiding the X-ray beam and focusing it to a specific location. These mirrors using total internal reflection require super smooth surface finish due to small wavelength of X-ray. Magnetorheological finishing is a computer-controlled technique used in the production of high-quality optical lenses. This process utilizes polishing slurries based on magnetorheological fluids, whose viscosity changes with the change in magnetic field. In this work, polishing potential of silicon mirrors by magnetorheological finishing process is examined to achieve nanometric surface finish for X-ray applications. The individual effect of parameters such as magnetizing current, working gap, rotational speed on surface roughness is investigated, and optimized parameters are identified. To investigate the physical essence underlying magnetorheological finishing process, the molecular dynamics simulations are used. Molecular dynamics simulation is used to study the atomic-scale removal mechanism of single-crystalline silicon in magnetorheological finishing process and attention is paid to study the effect of gap between the tool and the workpiece on surface quality. The outcome is promising and the final surface roughness achieved is as low as 6.4 nm. The surface quality is analyzed in terms of arithmetic roughness, power spectral density, and image analysis of scanning electron microscopy for uniform evaluation.

Experimental Research of Cluster Magnetorheological Finishing on Anodic Oxide Film of Aluminum

2016 ◽  
Vol 874 ◽  
pp. 158-166
Author(s):  
Run Chen ◽  
Jia Bin Lu ◽  
Qiu Sheng Yan ◽  
Xiao Lan Xiao ◽  
De Yuan Li
Keyword(s):  
Surface Roughness ◽  
Oxide Film ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Anodic Oxide ◽  
Anodic Oxide Film ◽  
Magnetorheological Finishing ◽  
Machining Time ◽  
Good Surface

The polishing experiments of anodic oxide film of aluminum were performed to research the influence of polishing parameters on the surface roughness and material removal rate in the cluster magnetorheological finishing (MRF). Experimental results demonstrate that a mirror effect can be reached when the anodic oxide film of aluminum is polished by the Cluster MRF. The roughness of the workpiece surface after polishing for 15 min is decreased from Ra 0.575μm to Ra 4.13nm and the material removal rate is 0.653mg/min. With the extension of the polishing time, the surface roughness rapidly declines at first and then slowly decreases. When the machining time is more than 15min, the anodic oxide film of aluminum is easily worn out, resulting in a sharp increase in the surface roughness. The machining gap between the workpiece and the polishing plate influences the polishing effect of anodic oxide film of aluminum. With the increase of the machining gap, the material removal rate decreases and the surface roughness increases. A good surface quality can be got at the machining gap of 1.1mm. The type and size of abrasive particles will directly affect the polishing effect of anodic oxide film of aluminum, and when using CeO2 abrasive with the particle size of W3, a higher material removal rate and a smaller surface roughness can be obtained.

Optics Manufacturing Using Magnetorheological Finishing

2008 ◽  
Vol 375-376 ◽  
pp. 274-277
Author(s):  
Gui Wen Kang ◽  
Fei Hu Zhang
Keyword(s):  
Dwell Time ◽  
Time Algorithm ◽  
Subsurface Damage ◽  
Numerical Control ◽  
Surface Shape ◽  
Magnetorheological Finishing ◽  
High Quality ◽  
Finishing Process ◽  
Surface Figure

Magnetorheological finishing (MRF) is a novel precision optical machining technology. Owing to its flexible finishing process, MRF can eliminate subsurface damage, smooth rms micro roughness and correct surface figure errors. The finishing process can be easily controlled by a computer. Through proper designing of numerical control, sphere and asphere optics can be machined by magnetorheological finishing with high quality. Optical sphere is machined using dwell time algorithm and surface shape 2 pt. PV has been improved from 0.17um to 0.07um.

Mechanism of material removal in ball end magnetorheological finishing process

Wear ◽  
2013 ◽  
Vol 302 (1-2) ◽  
pp. 1180-1191 ◽  
Author(s):  
Anant Kumar Singh ◽  
Sunil Jha ◽  
Pulak M. Pandey
Keyword(s):  
Material Removal ◽  
Magnetorheological Finishing ◽  
Finishing Process
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