An application of ultrasonic vibration to the deep drawing process

An experimental apparatus with the blank-holder or die plate vibrated in a radial mode was constructed in order to make the apparatus compact. The application of 20 and 28 kHz oscillation increases the LDR from 2.68 to 3.01, from 2.58 to 2.94 and from 2.38 to 2.77 respectively, in the case of cold rolled steel for deep drawing, cold rolled steel and 304 stainless steel. greater accuracy and deeper cups can be formed by stopping the oscillation after the maximum punch load rather than applying the oscillation throughout the deep drawing process. The radial vibration induces the axial vibration in the blank-holder or die plate and the axial vibration contributes strongly to the rise in the limiting drawing ratio (LDR) rather than the radial one. When one of the blank-holder and die plates is vibrated, the vibration in anti-phase is induced in the other. This means that both the blank-holder and the die plate should be simultaneously vibrated in anti-phase. Seasoning cracks of drawn cups can be avoided when the vibration is applied to the deep drawing process of 304 stainless steel sheets.