Ploughing-extrusion mechanism of V-shaped capillary micro-grooves based on surface of copper strip
(1.College of Mechanical Engineering, South China University of Technology, Guangzhou 510640, China2.广东省广州市华南理工大学机械工程学院3.State Key Laboratory of Solidification Processing,Northwestern Polytechnical University, Xian 710072, China)
Abstract: Using ploughing-extrusion process, the V-shaped capillary micro-grooves based on the surface of copper strip with thickness of 0.4 mm were obtained. When the ploughing depth is 0.3 mm and the groove interval is 0.24 mm, the groove width of the obtained structure is about 200 μm, the groove depth is above 400 μm, and the angle of grooves is less than 30？. The formation mechanism of ploughing-extrusion was analyzed using scanning electron microscope (SEM). The results show that the formation process consists of four steps, i.e. splitting-ploughing, extruding, forming and truing. There exist two critical states during the formation process. In the first state, a smooth U-shaped groove appears between two V-shaped grooves, and the compounded structure which comprised of V-shaped grooves and U-shaped grooves is obtained. In the second state, the U-shaped groove is evolved into a narrow crack, and the resulted V-shaped capillary macro-groove structure contains symmetric V-shaped grooves and narrow cracks. These two critical states are restricted by the groove interval (w) and the ploughing depth (ap), and related on the tool parameters simultaneously.
Key words: V-shaped groove; capillary structure; ploughing-extrusion