內溝紋鰭管旋壓成形之簡化CAE分析

A Simplified CAE Analysis of Ball Spinning for Grooved-Fin Tubes

許睿恆(Ruei-Heng Hsu)

指導教授 ： 林恆勝

國立虎尾科技大學/工程學院/創意工程與精密科技研究所/碩士(2010年)

https://doi.org/10.6827/NFU.2010.00044

摘要

溝紋鰭管在旋壓成形時，管件表面受到滾珠旋轉帶動而造成積料或隆起的現象，進而造成剝離之成形缺陷，本研究藉由DEFORM-3D有限元素軟體來模擬溝紋鰭管旋壓成形，釐清成形缺陷的原因。由於溝紋鰭管在進行旋壓模擬時，內部溝紋網格不易佈建，所以在模擬上簡化成薄壁管。探討滾珠直徑、軸向速率、主軸轉速、切向與軸向速率比、摩擦因子等參數，對於管件在旋壓過程中形成隆起高度、等效應變分佈、多餘變形因子與成形負荷之影響。

研究後有以下結論：隆起現象之成因為滾珠下壓量增加、滾珠直徑減少、軸向速率減緩、主軸轉速增加、切向與軸向速率比增加與摩擦因子增加，都會造成管件表面發生剝離的現象，其中以下壓量的影響最為明顯。

管件等效應變分佈的結果顯示滾珠直徑愈小，愈容易造成管件表面等效應變的增加，藉由多餘變形因子來分析管件旋壓之變形不均勻度，結果顯示滾珠直徑較小、軸向速率較慢、主軸轉速較快、切向與軸向速率比較大、摩擦因子較大時，變形不均程度較大。較明顯的現象是在下壓量0.2 mm滾珠直徑6 mm的條件下，滾珠對管件的作用較不易達到內表面，再加上旋壓是以螺旋進給方式成形，因此在管件外表面之等效應變遠大於均勻變形之應變值，因此多餘變形因子較高。

成形負荷的結果顯示，滾珠直徑對軸向與徑向的負荷影響最為明顯，軸向負荷隨滾珠直徑的減少、軸向速率增加、切向與軸向速率比減少、摩擦因子增加而增加；徑向負荷會隨滾珠直徑的增加、切向與軸向速率比增加、摩擦因子的增加而增加。

關鍵字

溝紋鰭管 ； 有限元素法 ； 旋壓

並列摘要

Build-up defect is likely to occur in ball spinning grooved-fin tubes. This work applies DEFORM-3D to simulate the process and to figure out the cause of the forming defect. Because of the difficuties encountered in generating elements in the tube fins, the simulation was simplified into spinning thin-wall tubes. The effects of ball size, axial speed, spindle rotation, tangential-to-axial speed ratio and friction factor on the build-up, distribution of effective strain, redundant deformation factor and forming loads were investigated.
The results show that build-up is caused by the increase of infeed, decreasing ball size and axial speed and increasing spindle rotation, speed ratio and friction factor. The effect of the infeed is the most influential.
The effective strain increases with smaller ball size, lower axial speed, higher spindle rotation, higher speed ratio and greater friction factor. Ball size is the most influential to the forming load. Phenomenon is more obvious in the next volume of 0.2 mm compression ball 6 mm in diameter under the conditions of the role of the ball on the tube more difficult to reach the inner surface, together with the feed screw by way of spinning forming, so the outer surface of the tube equivalent strain is much larger than the value of uniform strain deformation, so redundant deformation factor higher.
Axial forming load increases with smaller ball size, higher axial speed, lower speed ratio, lower speed ratio and greater friction factor. Radial forming load increases with larger ball size, higher speed ratio and greater friction factor.

並列關鍵字

grooved-fin tube ； ball spinning ； finite element method

參考文獻

[3] M.I. Rotarescu. A theoretical analysis of tube spinning using balls, Journal of Materials Processing Technology 54 (1995) 224-229.

[5] LI Yong, XIAO Hui, LIAN Bin, TANG Yong, ZENG Zhi-Xin, Forming method of axial microgrooves inside copper heat pipe, Trans. Nonferrous Met. Soc. China 18 (2008) 1229-1233.

[6] Y. Tang, Y. Chi, J.Ch. Chen. X.X. Deng, L. Liu, X.K. Liu, Zh.P. Wan, Experimental study of oil-filled high-speed spin forming micro-groove fin-inside tubes, International Journal of Machine Tools and Manufacture 47 (2007) 1059-1068.

[7] S.H. Zhang, Mao-Sheng Li, Yi Xu, D.C. Kang, Chun-Zhi Li, Introduction to a new CNC ball-spinning machine, Journal of Materials Processing Technology 170(2005)112-114.

[8] F.A. Hua, Y.S. Yang, Y.N. Zhang, M.H. Guo, D.Y. Guo, W.H. Tong, Z.Q. Hu, Three-dimensional finite element analysis of tube spinning, Journal of Materials Processing Technology 168 (2005) 68–74.