Energy-controlled rotary swaging process for tube workpiece

Abstract

With the development of manufacturing industry, metal tubes and rods are used more and more widely in automobile, aviation, and aerospace fields. Rotary swaging, a competitive plastic-forming technology for manufacturing tubes and rods, can realize net-shape forming for high-quality workpiece. However, in order to control the forming precision of tube or bar workpiece, the complex mechanical system was needed in the conventional swaging machine. In this paper, a rotary swaging process utilizing energy-controlled method is proposed, which can improve the flexibility of the process and control forming diameter of the tubes by changing the forming energy. In the swaging machine, a servo motor and its control system were used to change the speed of the rotary swaging spindle. And then, the swaging energy of the hammer die can be controlled. Rotary swaging experiments of pure copper tubes were conducted on the developed rotary swaging machine. These tubes with outer diameter of 8.0 mm and wall thickness of 1.0 mm were formed to necking tubes with different outer diameters. Meanwhile, the relationship between the speed of the spindle and the forming diameter of the formed tube was obtained. The metallographs of the formed tubes showed the compact structure and continuous streamline. To investigate the metal behavior under different energy of the hammer die, Transvalor Forge 2011 was used to simulate the rotary swaging process of tubes based on energy-controlled swaging method. The metal flows in radial, axial, and circumference directions, emerging axial elongation and necking deformation. Comparing the experimental results with the simulated ones, the deformation condition and thickness distribution are in good agreement.