Ultra-precision finishing of low expansion ceramics by compliant abrasive technologies: A comparative study

The ball end magnetorheological finishing (BEMRF) is an advanced nanofinishing process for flat, curved and freeform surfaces of ferromagnetic as well as diamagnetic materials. While finishing copper (diamagnetic material) by this process, a low finishing effect is obtained as its surface repels the externally applied magnetic field. In this work a magnetic simulation is carried out over both copper and ferromagnetic material. For the ferromagnetic material the simulation result shows a high flux density region below the tool tip. However in case of copper the magnetic flux density is too low for finishing. It is also observed through simulations that when copper workpiece is placed on a mild steel base the flux density improves marginally. This led to the idea of using a permanent magnet (in place of mild steel) as a base for finishing of copper using the BEMRF process. Using this technique copper was finished and the experimental results indicate that this method can realize ultra-precision finishing of copper.

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Investigation on Surface Finishing of Components Ground with Lapping Kinematics: Lapgrinding Process

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.223.879 ◽

2011 ◽

Vol 223 ◽

pp. 879-887 ◽

Cited By ~ 1

Author(s):

Arthur Alves Fiocchi ◽

Luiz Eduardo de Angelo Sanchez ◽

João Fernando Gomes de Oliveira ◽

Ioan Marinescu

Keyword(s):

Single Point ◽

Surface Finishing ◽

Grinding Wheel ◽

Average Surface Roughness ◽

Ultra Precision ◽

Steel Aisi ◽

Finishing Processes ◽

Abrasive Process ◽

Precision Finishing ◽

Stainless Steel Aisi

Over the last three decades, researchers have responded to the demands of industry to manufacture mechanical components with geometrical tolerance, dimensional tolerance, and surface finishing in nanometer levels. The new lapgrinding process developed in Brazil utilizes lapping kinematics and a flat grinding wheel dressed with a single-point diamond dresser in agreement with overlap factor (Ud) theory. In the present work, the influences of different Ud values on dressing (Ud = 1, 3 e 5) and grain size of the grinding wheel made of silicon carbide (SiC = 800, 600 e 300 mesh) are analyzed on surface finishing of stainless steel AISI 420 flat workpieces submitted to the lapgrinding process. The best results, obtained after 10 minutes of machining, were: average surface roughness (Ra) 1.92 nm; 1.19 µm flatness deviation of 25.4 mm diameter workpieces and mirrored surface finishing. Given the surface quality achieved, the lapgrinding process can be included among the ultra-precision finishing processes and, depending on the application, the steps of lapping followed by polishing can be replaced by the proposed abrasive process.

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Ultra-Precision Finishing of Micro Aspherical Surface by Ultrasonic Vibration Assisted Polishing

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.291-292.349 ◽

2005 ◽

Vol 291-292 ◽

pp. 349-354 ◽

Cited By ~ 2

Author(s):

H. Suzuki ◽

R. Kawamori ◽

M. Miyabara ◽

T. Okino ◽

Yasuto Hijikata ◽

...

Keyword(s):

Digital Image ◽

Diamond Wheel ◽

Optical Devices ◽

Image Sensors ◽

Aspherical Surface ◽

Digital Devices ◽

Ultrasonic Assisted ◽

Ultra Precision ◽

Glass Lenses ◽

Precision Finishing

Micro axis-symmetric aspherical glass lenses are being increasingly used in digital devices and optical devices. The glass lenses are molded by using micro ceramic dies such as tungsten carbide [1].Recently, as the pixel number of digital image sensors increases, the accuracy of micro molding dies are required to be much more precise than ever [2]. In this study, ultrasonic assisted polishing method is proposed and developed in order to finish micro axis-symmetric aspherical dies which were pre-ground with a diamond wheel [3]. In this paper, the proposed polishing method was applied to the micro aspherical molding dies to finish form compensation processing.

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