Experimental Study on the Effects of Alumina Abrasive Particle Behavior in MR Polishing for MEMS Applications
2. Characteristics of MR Fluids
2.1. Polishing Principle Using MR Fluids
2.2. Flow Characteristics and Material Removal Rate in MR Polishing
3. Experimental Setup and Polishing Conditions
4. Experimental Results and Analysis
4.1. Basic Experimental Results
4.2. Groove Polishing Using Slurry No.3
- Effects of alumina abrasive particle behavior for MR polishing on BK7 glass were experimentally studied.
- Viscosity of the MR fluids increased with increased imposed magnetic fields and electric currents.
- Material removal rate increases with increased wheel speed and electric current; however, the rate of increase decelerated when the values exceeded certain levels. This phenomenon is due to chain structure breakage between the MR particles, and slipping between the wheel and the MR fluids by excessive shear stress.
- Alumina slurry No.3 showed the best results. Using the conditions prescribed for this slurry, groove polishing on BK7 glass was performed. Outstanding surface roughness of Ra=3.8nm was obtained.
- From the experimental results, it can be seen that the MR polishing method can be applied to fabricate micro parts, especially in MEMS.
- It will be possible to obtain more advanced results through appropriate combinations of MR particles, micro abrasives, and process parameters.
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|Structure||Single-crystal cubic c-cut|
|Surface hardness (GPa)||2.47|
|Young's module (GPa)||110|
|Micro powder iron grade R-2430|
|Apparent density||2.0 - 3.0|
|True density||7.7 Maximum|
|Average particle diameter||4-6 microns|
|% iron||99.5 max|
|% carbon||0.05 max|
|% Oxygen||0.5 max|
|% Nitrogen||0.1 max|
|Slurry No.||Slurry condition (wt %)|
|Alumina slurry No.1||Al2O3 particle(0.05μm) 10% + DI water 88.5% + Glycerin 0.5% + Na2CO3 1%|
|Alumina slurry No.2||Al2O3 particle 3% + commercial stabilizer(Virgo 222YT-P) 5%+ DI water 92%|
|Alumina slurry No.3||Al2O3 particle 5% + commercial stabilizer(Virgo 222YT-P) 5%+ DI water 90%|
|Alumina slurry No.4||Al2O3 particle 10% + commercial stabilizer(Virgo 222YT-P) 5%+ DI water 85%|
|No.||Wheel speed (rpm)||Electric current (A)||Polishing Time||Polishing depth|
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Kim, D.-W.; Cho, M.-W.; Seo, T.-I.; Shin, Y.-J. Experimental Study on the Effects of Alumina Abrasive Particle Behavior in MR Polishing for MEMS Applications. Sensors 2008, 8, 222-235. https://doi.org/10.3390/s8010222
Kim D-W, Cho M-W, Seo T-I, Shin Y-J. Experimental Study on the Effects of Alumina Abrasive Particle Behavior in MR Polishing for MEMS Applications. Sensors. 2008; 8(1):222-235. https://doi.org/10.3390/s8010222Chicago/Turabian Style
Kim, Dong-Woo, Myeong-Woo Cho, Tae-Il Seo, and Young-Jae Shin. 2008. "Experimental Study on the Effects of Alumina Abrasive Particle Behavior in MR Polishing for MEMS Applications" Sensors 8, no. 1: 222-235. https://doi.org/10.3390/s8010222