溫度效應與高轉速下之盤型彈簧施力對 高速氣浮主軸刀具夾持力之影響研究

Investigation of the exerting force of disc springs in affecting the clamping effectiveness of cutting tool under influences of temperature and high rotation speed for high-speed air bearing spindle systems

張國鑫(Kuo-Hsin Chang)

指導教授 ： 陳永樹

元智大學/工程學院/機械工程學系/碩士(2009年)

摘要

高速切削是近年來切削加工方面的主要發展趨勢，而高速主軸為高速切削的關鍵技術核心，需具備高精度、耐磨損等特點，因此極具開發與應用價值。隨著氣浮軸承技術的逐漸成熟，轉速每分鐘高達數萬甚至數十萬轉之氣浮式高速主軸，已經被廣泛的應用在如PCB鑽孔機、以及晶圓切割機等領域。國內工業界對於氣浮軸承研究起步較晚，面臨高速化切削加工的市場競爭壓力下，開發氣浮軸承關鍵技術及相關應用技術，是值得投入的重要課題。本研究針對氣浮主軸之由盤型彈簧壓縮變形所產生的回復力，所轉而提供之拉刀力，在高轉速與溫度效應等因素影響下，對刀具夾持效應之影響，進行理論分析與相關實驗。
氣浮主軸系統之拉刀機構，是由盤型彈簧、鑽嘴、拉桿襯套所組成。此拉刀機構用途在夾持刀具，以利主軸系統進行切削加工。若拉刀機構所提供之拉刀力不足則直接影響主軸的切削力、切削移除率、縮短刀具壽命及振動等問題。
研究首先利用實驗驗證盤型彈簧的彈性係數曲線模式，並結合有限元素模擬分析討論離心力對盤型彈簧變形之影響；此外，並進一步研究加工時之溫度升高對盤型彈簧拉刀力的影響。同時，亦利用理論計算獲得這些狀態下對應盤型彈簧形變所能提供之拉刀力。因此，結合盤型彈簧先預壓變形，經高速旋轉的離心力作用，再加上溫升效應等諸類似實際應用情況，綜合其結果，對於氣浮主軸在設計和加工上發揮實用之具體價值。

關鍵字

高速主軸、氣浮軸承、盤型彈簧、刀具、離心力、溫度、拉刀力

並列摘要

With the advent of high speed cutting, the high speed spindle plays the key role in the core techbnologies. It has to have characteristics of high pecision and low wear and thus deserves continuous development for wide applications. Following the grow up of the air bearing technology, the high speed spindles that are used in printed circuit board(PCB) drilling and wafer cutting often runs at tens or hundreds of thousands revolutions per minute(RPM). The start up of air bearing spindle research is somehow a little bit late domestically. However, it is the era of high speed cutting in the competitve global market. It is worthy to put effors in the relating air bearing spindle technology and application developments. Thus,the study takes both theoretical, analytical and experimental approaches to investigate the exerting force that results from the disc spring rebound in affecting the clamping effectiveness of cutting tool when under temperature and high rotation for high-speed air bearing spindle systems.
The draw bar mechanism in the air bearing spindle system consists of disc springs, tool holder and pulling rod with its bushing. It clamps and holds to cutting tool in position during the machinning processes. The cutting forces, chip removal rate, tool life and vibrations all affected by the tool holding force provided by the draw bar mechanism.
First, the study conduts physical tests on the variations of disc spring stiffness versus loading. It is then combined with the finite element analysis(FEA) to explore the deformation of the disc spring as affected by the centrifugal forces. Besides, the influence of temperature rise on disc spring deformation in terms of draw bar force is also considered. Therefore, the discussion integrates the pre-load deformation of disc spring, the centrifugal force in high speed rotation, and the temperature effect…etc. of those conditions in the real cutting process. It is expected that the corresponding results can be benefical to the air bearing spindle design and machinning process applications.

並列關鍵字

centrifugal force, cutting tool, disc spring drawbar force, gas bearing, high speed spindle, temperature

參考文獻

[2] 「精密切削投影片」，國立高雄應用科技大學，機械工程系，機械與精密工程研究所，許光城教授教學網頁，民國93年12月。

[9] Powell, J. W., “Design of Aerostatic Bearing”, Machinery Publishing Co. Ltd.,London, 1970.

[15] Wempner, G. A., “Axially Symmetric Deformation of a Shallow Conical Shell”, Doctoral thesis, University of Illinois, Urbana, III., 1957.

[19] Bagavathiperumal, P.; Chandrasekaran, K.; Manivasagam, S. , “Elastic load-displacement predictions for coned disc springs subjected to axial loading using the finite element method” , Journal of Strain Analysis for Engineering Design. Vol. 26, pp. 147-152. July, 1991.

[20] Yahata, N. et al., “Analysis of coned disc spring by finite element method”, Trans. Jpn. Soc. Mech. Eng., Ser C, 59 (567), pp. 3494-99, 1993.