| Summary: | 碩士 === 國立屏東科技大學 === 機械工程系所 === 101 === In this study the characteristics of surface roughness for area on or near quiescent point on the top of curved surface in high speed milling Al 6061-T-6 has been investigated. Firstly, a comparison of surface roughness on the quiescent point area generated from using a 3 axles machine tool with a 5 axles machine tool was performed under same cutting parameters. Furthermore, a combination of milling parameters was found to produce optimum surface roughness by a five axles machine tool. An average surface roughness (Ra) on the area of quiescent point was measured alter experiments has been conducted. The results showed that the surface roughness (Ra) on the quiescent point area of curved surface is 0.709μm, on the expanded area including both sides 5mm away from the quiescent point area is 0.587μm by using a 3 axles machine tool. The values for using a 5 axles machine tool are 0.396μm aud. 0.264μm respectively. In the second step, a 5 axles machine tool is used to conduct experiments. The selected milling parameters are tool inclined angle with 30°,20°,10°,0°,-10°,-20°and-30°；and. feed rate with 1000mm/min, 2000mm/min and 3000mm/min. If can be. seen that an optimum surface roughness 0.211μm has obtained on the quiescent point area with milling parameters for -10°and 1000mm/min. A 0.279μm found on the expanded area including both sides 5mm away from the quiescent point area. With same willing parameters. Both surface roughness is within the required quality for polishing Ra is less than 0.4μm. This study proved that the characteristics for adjusting inclined angle of tool can effectively improve surface roughness to meet the polishing standard requirement. The achievement causes a reducing in manufacture time and an increasing in production efficiency.
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