Main Sector of relevance\IRC classification 10. Other Industrial Manufacturing Technologies


10.5 Finishing technology for optical and semiconductor parts with the use of magnetorheological fluids

Developers’ contact information

State Scientific Institution “The A.V.Lykov Institute of Heat and Mass Transfer of National Academy of Sciences of Belarus”
15 P.Brovka Street, Minsk BY-220072
Tel.: +375 (17) 284-21-38, fax: +375 (17) 292-25-13

L.K. Gleb, Candidate of Engineering Science
Tel.: +375 (017) 284-13-62

Summary

The magnetorheological finishing technology (MRFT) is a computer-monitored final polishing process for optical and semiconductor parts ensuring both high geometric precision and high quality grade of their surface. The magnetorheological finishing method is based on regulating magnetorheological fluid (MRF) properties by means of magnetic field variation. Magnetic field converts thin-consistency MRF into a viscoplastic medium suitable for finishing of various materials.

Description

The MRFT is realized through different magnetorheological finishing module (MRFM) constructions (one of them is shown on Figure 1) and various MR compounds. The MRFM is mounted on a base machine, its kinematical scheme and construction chosen according to the type and identification data on optical and semiconductor parts under treatment. The MRFT is a fully automatic computer-monitored treatment process which, unlike other common finishing technologies, requires no time-consuming tool preparation and part-specific size adjustment.

Fig. 1 – Magnetorheological finishing module

Fig. 1 – Magnetorheological finishing module


Various MRFM constructions and base machine configurations allow final polishing of parts of all geometrical forms: spherical, aspherical, bowed and dished, flat. The size range is from 5 mm to 2m and more. Magnetorheological finishing is suitable for such materials as noted below:

Technology type

Technical advantages and economic benefits

The MRFT ensures high-quality and high-precision part surfaces, which remains an impossible task for standard finishing technologies. Surface roughness mean root square value, Rq, can amount to 3 ÷ 10 Angstrom units while form defect mean root square value σ rms, is ± λ/60÷λ/100 (λ=0,6328 μm).

Technology differentiation and uniqueness

Cooperation with optical and electronic production enterprises for the purpose of constructing magnetorheological finishing packages and machines to process all kinds of high-precision optical parts, astronomical optics as well as semiconductor plates.

Context in which technology was identified

At the Federal State Unitary Enterprise “Scientific Production Association “Optika””, RF, Moscow (FSUE “SPA “Optika””).

Technological keywords

Magnetorheological finishing technology, magnetorheological fluid, magnetorheological finishing module, optical and semiconductor parts.

Development Stage

Intellectual property rights

Range of applications

Magnetorheological finishing technology as well as the developed equipment can be used in production:

Classifier Used at the EU Innovation Relay Centres

Preferable Regions

Practical experience

State scientific institution “Heat and Mass Exchange Institute of the National Academy of Sciences of Belarus” have been carrying out researches on magnetorheological finishing since 1990. Together with Optical Production Center of the University of Rochester, USA, it also held some cooperative research activities concerned with studying fundamental basis for magnetorheological fluid production intended for optical parts polishing. Their joint activities resulted in a revolutionary and world-renowned technology named magnetorheological finishing (MRF) (as per international nomenclature).
In 2006÷2008 State scientific institution “Heat and Mass Exchange Institute of the National Academy of Sciences of Belarus” cooperated with FSUE “SPA “Optika”” to develop a test model of an optical part finishing module based on use of magnetorheological fluids.
In 2008 they conducted studies in accordance with an agreement on constructive cooperation concluded between SSI “Heat and Mass Exchange Institute of the National Academy of Sciences of Belarus” and the Institution of the RF Academy of Science “Institute of High-purity Substances Chemistry” (IRFAS IHPSC).
“Application of magnetorheological finishing technology to process zinc chalcogenide optical semiconductor products”. The results of the experiments testify to a possible high-quality finishing for polycrystalline zinc sulphide with the use of magnetorheological finishing technology.

Environmental impact

When applying the magnetorheological finishing technology it is essential to follow all the norms and regulations specified for certain material finishing operations in optical and electronic industries. Magnetorheological fluids used for MRF are not toxic and they have no environmental impact.

Type of collaboration sought

Terms and restrictions

Available technical assistance