Mechanical polishing of fan blade by a prototype random-orbital tool
The main objective of this study is to better understand the influence of water and air coolant-induced surface texturing and its characterization by a new random-orbital polishing method and prototype tool. Mechanical polishing is the most common process to remove surface irregularities on fa...
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sg-ntu-dr.10356-1549262023-03-11T18:04:52Z Mechanical polishing of fan blade by a prototype random-orbital tool Danaraj, Edgar Jeevan Yeo Swee Hock School of Mechanical and Aerospace Engineering MSHYEO@ntu.edu.sg Engineering::Mechanical engineering Engineering::Manufacturing The main objective of this study is to better understand the influence of water and air coolant-induced surface texturing and its characterization by a new random-orbital polishing method and prototype tool. Mechanical polishing is the most common process to remove surface irregularities on fan blades such as scallop height features, while maintaining the required dimensional limits and textures. After the polishing process, the part will undergo shot peening, vibratory finishing and later, painting and coating at the final stages. It is therefore essential for the fan blade surface to pre-treated with appropriate surface conditions to promote good surface-to-surface adhesion at the end of the manufacturing cycle. The existing method uses a single-axis rotary polishing tool where an external water coolant source is performed ad-hoc. This polishing method can produce average surface roughness, Ra, of 1.0 µm that satisfies the requirement. However, this form is aggressive and has a high material removal rate, resulting in excessive reduction in material thickness, thus warrants rejection of costly fan blade. The criteria require surface roughness, Ra, between 0.8 to 1.0 µm and maximum height profile Rz, between 5.0 to 6.0 µm for post-polishing condition, while maintaining low material removal rate to prevent under-thickness of the fan blade. Experimental trials were performed on fan blade specimens at the leading-edge sections and its surface topography characterized by coherence correlation interferometry. A range of different abrasive grit sizes was tested for suitability of media selection. Integrating in-line cooled air with deionized water to the process achieved desirable surface roughness, Ra, of 0.8 µm and height profile Rz, of 5.8 µm, while simultaneously removing all traces of scallop height features and maintaining the leading-edge thickness within tolerance. Taking into consideration that the surface texture measurements are random in nature, the corresponding polishing methods were also analyzed with statistical functions by fast Fourier transform (FFT) and power spectral density (PSD). Comparison between the surface texture parameters or statistical functions with the corresponding polishing methods, were then established. The surface integrity of the polished fan blade and wear condition of the abrasive disk are also reported in this study. Master of Engineering 2022-01-17T00:25:33Z 2022-01-17T00:25:33Z 2021 Thesis-Master by Research Danaraj, E. J. (2021). Mechanical polishing of fan blade by a prototype random-orbital tool. Master's thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/154926 https://hdl.handle.net/10356/154926 10.32657/10356/154926 en This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University |
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Engineering::Mechanical engineering Engineering::Manufacturing Danaraj, Edgar Jeevan Mechanical polishing of fan blade by a prototype random-orbital tool |
description |
The main objective of this study is to better understand the influence of water and air
coolant-induced surface texturing and its characterization by a new random-orbital
polishing method and prototype tool. Mechanical polishing is the most common process
to remove surface irregularities on fan blades such as scallop height features, while
maintaining the required dimensional limits and textures. After the polishing process, the
part will undergo shot peening, vibratory finishing and later, painting and coating at the
final stages. It is therefore essential for the fan blade surface to pre-treated with
appropriate surface conditions to promote good surface-to-surface adhesion at the end of
the manufacturing cycle. The existing method uses a single-axis rotary polishing tool
where an external water coolant source is performed ad-hoc. This polishing method can
produce average surface roughness, Ra, of 1.0 µm that satisfies the requirement.
However, this form is aggressive and has a high material removal rate, resulting in
excessive reduction in material thickness, thus warrants rejection of costly fan blade. The
criteria require surface roughness, Ra, between 0.8 to 1.0 µm and maximum height
profile Rz, between 5.0 to 6.0 µm for post-polishing condition, while maintaining low
material removal rate to prevent under-thickness of the fan blade. Experimental trials
were performed on fan blade specimens at the leading-edge sections and its surface
topography characterized by coherence correlation interferometry. A range of different
abrasive grit sizes was tested for suitability of media selection. Integrating in-line cooled
air with deionized water to the process achieved desirable surface roughness, Ra, of 0.8
µm and height profile Rz, of 5.8 µm, while simultaneously removing all traces of scallop
height features and maintaining the leading-edge thickness within tolerance. Taking into
consideration that the surface texture measurements are random in nature, the
corresponding polishing methods were also analyzed with statistical functions by fast
Fourier transform (FFT) and power spectral density (PSD). Comparison between the
surface texture parameters or statistical functions with the corresponding polishing
methods, were then established. The surface integrity of the polished fan blade and wear
condition of the abrasive disk are also reported in this study. |
author2 |
Yeo Swee Hock |
author_facet |
Yeo Swee Hock Danaraj, Edgar Jeevan |
format |
Thesis-Master by Research |
author |
Danaraj, Edgar Jeevan |
author_sort |
Danaraj, Edgar Jeevan |
title |
Mechanical polishing of fan blade by a prototype random-orbital tool |
title_short |
Mechanical polishing of fan blade by a prototype random-orbital tool |
title_full |
Mechanical polishing of fan blade by a prototype random-orbital tool |
title_fullStr |
Mechanical polishing of fan blade by a prototype random-orbital tool |
title_full_unstemmed |
Mechanical polishing of fan blade by a prototype random-orbital tool |
title_sort |
mechanical polishing of fan blade by a prototype random-orbital tool |
publisher |
Nanyang Technological University |
publishDate |
2022 |
url |
https://hdl.handle.net/10356/154926 |
_version_ |
1761781965986463744 |