Improving ironing performance by using dies subjected to radial vibration: a study of ultrasonic vibration ironing process I

摘要

In the manufacturing of thin-walled cups by metal forming processes, the use of high viscosity lubricants, which would inevitably require strong and non-environment friendly degreasing agents such as fluorocarbons, has been restricted in order toreduce environment pollution. This problem can be solved, for example. by using low-viscosity lubricants, such as water-soluble oil. However, this generally results in poor forming (e.g.ironing) performance which must be solved in some other way. Theauthors, therefore, attempt to apply ultrasonic vibration to dies for ironing process both in the axial and radial directions in an effort to improve the lubricity of the die. From the experiments using aluminum and steel specimens, it is found that inthe case of radial vibration ironing, despite the use of low-viscosity lubricants, the limiting reduction ratio of wall thickness (LRRWT) and product precisions are improved as compared to conventional ironing. In addition. FEM is used to investigate themechanism of improvement of LRRWT.