| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
Titanium alloy has superior characteristics such as lightness, high strength and high corrosion resistance. These characteristics make Titanium alloy highly suited for aircraft parts and medical implants. Although Titanium is a very useful material and becoming more in demand, we are faced with difficulties in working the material to manufacture products. Especially, in the case of turning, Titanium alloy is chemically active, therefore causing chips to adhere to the tool tip. Accordingly, when the adhesive chips separate from the tool tip, they take with them part of the tool material, causing severe wear. Another issue is that chips can become entangled between tool and workpiece. This results in damage to the surface of the workpiece and the surface roughness increases. In this research, we have proposed the use of ultrasonic vibration assisted cutting of Titanium alloy in order to overcome these problems. By applying ultrasonic vibration to the tool tip (20kHz, 0.03mm), interrupted
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cutting, rather than continuous cutting, can be applied. This technology may enable us to prevent the adhesion and entanglement of chips, improving tool wear and surface roughness of the workpiece.
Below is a summary of the conclusions obtained through this research.
1)Prior to conducting the experiments, we carried out computer simulated cutting of Titanium alloy. This computer simulated cutting led us to predict that compared to conventional cutting without ultrasonic vibration, ultrasonic vibration assisted cutting would reduce the temperature at the tool tip by 100 C.
2)Using ultrasonic vibration cutting of Titanium alloy, we succeeded in reducing the cutting force to one third of that in conventional cutting.
3)Ultrasonic vibration assisted cutting of Titanium alloy shows more effective chip discharge in comparison to conventional cutting. Flow type chips were discharged and no entanglement was observed.
4)Compare to conventional cutting, an improvement in surface roughness is observed in the case of ultrasonic vibration assisted cutting of Titanium alloy. Under following conditions: cutting speed of 20 m/min, depth of cut of 0.1 mm, feed rate of 0.1 mm/rev, nose radius of 0.4 mm, a surface roughness Ry of 3.1 μm was achieved with ultrasonic vibration assisted cutting, and with conventional cutting, 4.0μm.
5)In regards to cutting fluid supply methods, comparisons were made of wet cutting, semi-dry cutting and dry cutting. We found that, in terms of minimizing tool wear, semi-dry cutting was the most suitable for ultrasonic vibration assisted cutting of Titanium alloy.
6)On investigating the effect of cutting speed in ultrasonic vibration assisted cutting, we discovered that a cutting speed of 30 m/min showed the best performance. This speed is approximately 30 % of the maximum speed of the ultrasonic vibration at the tool tip. Less
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