The effect of the reduction in load by ultrasonic vibration on the compression of aluminum cylinders is investigated. The differences in load by the vibration amplitude and compression speed are examined between pure aluminum A1050 and Al-Mg alloy A6063. The amount of stress reduction increases proportionally to vibration amplitude. The dependences of the stress reduction on the material and compression speed were small. Grain size was not changed in the deformed material by ultrasonic vibration. From these results, it is estimated that the material causes an elastic stress cycle accompanied by a final plastic deformation per unit ultrasonic vibration stroke during the compression and that the average stress is detected using the load cell on the compression equipment. The amount of stress reduction can be estimated from the simple equation using the ratio of ultrasonic vibration amplitude to material height. This idea will be useful for the advancement of compressive working using ultrasonic vibration.

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Presently, high accuracy is required to fabricate several automotive parts, such as engine parts, manufactured by tube bending processes. In an effort to achieve this requirement, we investigated a new tube-draw bending method using an ultrasonic-vibration plug. Firstly, we developed a new bending machine using an axial-ultrasonic-vibration plug at a frequency of 20 kHz and a maximum amplitude of 8μm (0-p). Secondly, we experimented on the tube-draw bending of carbon steel, stainless steel and titanium tubes. From the result of this study, we clarified that there are several advantages of the proposed ultrasonic-vibration tube-draw bending method, such as reduction in bending force and improvement in accuracy in terms of bending dimensions.

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