Pipe reduction of miniature inner grooved copper tubes through rotary swaging process
(1. Key Laboratory of Surface Functional Structure Manufacturing of Guangdong High Education Institutes,
South China University of Technology, Guangzhou 510640, China;
2. School of Chemistry )
South China University of Technology, Guangzhou 510640, China;
2. School of Chemistry )
Abstract: A rotary swaging machine was applied to fabricating pipe reduction for miniature inner grooved copper tube (MIGCT) heat pipes. Compared with conventional swaging method, the axial feed of the designed rotary swaging machine was reached by a constant pushing force. The deformation of grooves in pipe reduced section during rotary swaging was analyzed. The shrinkage and extensibility of pipe reduction were measured and calculated. Furthermore, four aspects, including outer diameter, surface roughness, extensibility and processing time of pipe reduction, which were influenced by the pushing force, were considered. The results show that the tube wall thickness increases gradually along the z-axis at sinking section. However, the outer diameters, surface roughness and micro-cracks at reduced section tend to decrease along the z-axis. Besides, the effect of variation in the pushing force on the extensibility is limited while an increase in the pushing force results in a decrease of surface roughness. Therefore, a large pushing force within the limit is beneficial to pipe reduction manufacturing during rotary swaging process.
Key words: rotary swaging; radial forging; stepped tube; pipe reduction; inner grooved tube; tube sinking; pushing force; surface roughness