Initial experiment for embossing a 3-D microstructure on the inside wall of a wound tube by an electromagnetic compression process

Abstract

The purpose of this study is to discuss the feasibility of an economical electromagnetic forming (EMF) process to fast manufacture microstructure on the inside well of a wound thin tube. To form the three-dimensional (3-D) microstructure on the inside wall, a copper film is wound onto the forming mandrel and then inserted into the forming coil that provides external compressive force on the tube surface using the EMF process. This study proposes an inexpensive method that uses a reverse electro-discharge machining process with a homocentric path to manufacture the forming mandrel. The thickness effects of the single tube on the formed microstructure are investigated by an economical EMF device with low voltage and high capacitance. In addition, a composite tube is proposed to prevent electromagnetic field loss, reduce the gap, and provide good contact force. By using a composite tube in an EMF process, the forming depth and the profile completeness of the microstructure are improved.

Keywords:

• 3-D microstructure forming
• thin copper tube
• forming mandrel
• electromagnetic forming

Acknowledgments

Help from the Metals Industry Research and Development Corporation, Kaoshung, Taiwan, R.O.C., in the measurement of the peak current is gratefully acknowledged.