Experimental study of oil-filled high-speed spin forming micro-groove fin-inside tubes

• Published in: International journal of machine tools & manufacture Vol. 47; no. 7; pp. 1059 - 1068
• Main Authors: Tang, Y., Chi, Y., Chen, J.Ch, Deng, X.X., Liu, L., Liu, X.K., Wan, Zh.P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2007; Elsevier
• Subjects: Applied sciences; Exact sciences and technology; Fin-inside tube; Fundamental areas of phenomenology (including applications); Inelasticity (thermoplasticity, viscoplasticity...); Mechanical engineering. Machine design; Micro-groove; Oil-filled high-speed spinning; Oil-film dynamic lubrication; Physics; Solid mechanics; Structural and continuum mechanics; Fin-inside tube; Oil-film dynamic lubrication; Oil-filled high-speed spinning; Micro-groove; Lubricating oil; Viscosity; Tube; Roughness; Dry friction; Inelasticity; Squeeze film; High speed; Floating body; Surface conditions; Dynamic pressure; Production process; Forming; Fin; Rough surface; Wall thickness; Experimental study; Layer thickness; Operating conditions; Lubricating film; Groove; Spinning; Spinning(mechanics)
• ISSN: 0890-6955; 1879-2170
• DOI: 10.1016/j.ijmachtools.2006.10.001

This paper presents an oil-filled high-speed spinning process of manufacturing micro-groove fin-inside tubes. In spinning, a high-pressure oil-film, which squeezes the tube outer-wall, is formed as the spinning speed increases. A floating mandrel extrudes the tube inside wall to form the micro-grooves/fins continuously. By experiments of spinning micro-groove fin-inside tubes, this paper analyzes the influences of each process parameter on the formation quality, and optimizes each parameter. The experimental results show that the dynamic pressure can significantly improve the stability of spinning and the quality of finished surface; the minimum thickness of oil-film is decided by the spinning speed and the oil viscosity directly. In the case of full oil dynamic lubrication, there is no obvious scrape on tube surfaces. The main factors affecting the groove depth and the surface roughness are the ratio ( α) of the wall thickness of the tube before drawing to the finished one, the material plasticity, the ratio ( β) of drawing to spinning, the spinning speed ( n), and lubricating state, etc. The axial drawing force mainly depends on the friction between the floating mandrel and the tube internal wall, the friction between the reducing mold and the outer surface, and plastic deformation resistance in the reducing mold area and spinning area as well.