The Study of Micro-Arc Oxidation Process Aided Micro Milling on Titanium
Date Issued
2014
Date
2014
Author(s)
Hsiao, Hung-Chun
Abstract
This study first discussed the parameter of the oxide film generated from MAO process, and then use the MAO process to solve the burr and surface roughness problem made by micro-milling. Then, the study compares the results of pre-processed workpiece surfaces with the processed ones.
No matter the parameters of Duty Cycle is 1/10 or 1/5, both of the results show that the oxide film became thicker while the voltage affect time became longer. However, the process time of 1/10 is twice longer than that of 1/5. In addition, the study has to use thicker workpiece to avoid deflection, but it also causes film grow characteristics which will prolong the process time. Thus, this study chooses the parameter Duty Cycle 1/5 for more efficiency.
This study uses the cutter with the diameter of 0.7mm and 100mm/min feed. It was found that the burr height will simultaneously increase when the cutting depth becomes deeper. Also, the different sides of the slot, causing climb or conventional milling, will give rise to different burrs heights too. Compare to the workpieces with conventional milling, the burrs heights of that with climb milling are higher and will occur in smaller cutting depth.
Comparing the pre-processed workpiece with the workpieces processed by MAO with 36 s, 60 s, and 90 s voltage affect time, the study discovers that the cutting depth which leads to the formation of burrs is increased from 2.8μm to 5.8μm、8.4μm、10μm. In other words, MAO process can moderate the burr problem.
When cutting depth was shallow, the measured surface roughnesses were considerably higher than the theoretical surface roughness. This indicates that the surface generation mechanism at these cutting depth will be affected by not only geometric considerations, but also the minimum chip thickness, ploughing, and elastic recovery effects. Surface roughness, which has no significant relation with the thickness of oxide film, will decrease when cutting depth approach 20μm, but begins to increase again after 20μm~30μm.
Cutting under different cutting depths will result in different ways, which imply that the oxide film is only a physical accumulation on the surface of titanium. Considering that the oxide film doesn’t adhere to the metal strongly, the removal of it is easy and brittle.
Subjects
微銑削
微弧氧化
毛邊
鈦
薄膜結合度
Type
thesis
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