Implementation of high speed of silicon using diamond coated tools with air blowing
Ductile mode machining of silicon is hard to obtain due to the brittleness of silicon and hardness of tool materials. A brittle material will have little tendency to deform before it fractures when it is subjected to stress. Ceramic materials such as silicon carbide and silicon nitride are hard a...
| Main Authors: | , , |
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| Format: | Book Chapter |
| Language: | English |
| Published: |
IIUM Press
2011
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/23609/ http://irep.iium.edu.my/23609/ http://irep.iium.edu.my/23609/4/chp30.pdf |
| Summary: | Ductile mode machining of silicon is hard to obtain due to the brittleness of silicon and
hardness of tool materials. A brittle material will have little tendency to deform before it
fractures when it is subjected to stress. Ceramic materials such as silicon carbide and silicon nitride
are hard and brittle to be machined. According to Thimmaiah et al. [1] brittle materials are
difficult to machine while maintaining the desired surface roughness, yet Sreejith [2] specified
that ductile machining of brittle materials is possible under controlled machining conditions.
This is supported by works of J. Yan et al. [3], which stated that silicon is nominally brittle
material but can be deformed plastically in machining, yielding ductile chips under the
influence of high hydrostatic pressure.
According to Mariayyah and Ravishankar [4], conventional grinding of these materials leaves
micro-cracks and pits on the surface. Other than that, these materials insist on further
finishing as lapping and polishing to ensure high quality surface finish. These finishing
operations such processes can be avoided if the materials can be machined similar to metals in
ductile regime machining. Recent machining studies on brittle materials such as silicon and
germanium have shown that ductile regime machining using a single point diamond tool can
produce a mirror-like finish wherein various machining parameters are provided and properly
controlled such as spindle speed, depth of cut and feed rate, hence the material deforms
plastically during machining.
D.J Stephenson [5] stated that in conventional single point diamond turning, ductile materials
such as aluminum and copper are usually used as material for mirror quality surface products.
With the recent use of the single point diamond turning, strong demands for the ultraprecision
machining of brittle materials such as silicon, germanium and glass are increasing.
Hence, many works concerned with the machining of the brittle material have been
conducted. As a result of a ductile-to-brittle transition, it is not easy to machine brittle
materials to obtain mirror quality surface in nature due to the occurrence of the fracture.
Y.S. Liao et al. [6] showed that in recent years, high speed machining (HSM) technology is
becoming matured due to the advance of machine tool and control system. A higher metal
removal rate is not the only advantage of HSM. It has the features of lower cutting force,
improvement of the surface quality, no critical heat of the work piece, etc.
This chapter focuses on how to improve the surface roughness and integrity of silicon by
using air blower at higher pressure in conventional machining. Thus, the optimal machining
parameters can be obtained to yield the predicted surface roughness analyzed by ANOVA. |
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