工具機振動與加工件表面粗糙度之關聯性探討

Study of Correlation Between Machine Tool Vibration and Work Piece Surface Roughness

陳韋任(Wei-Ren Chen)

指導教授 ： 鄭志鈞

國立中正大學/工學院/機械工程學系/碩士(2015年)

摘要

本論文之主旨為探討加工時機台振動與加工件表面粗糙度之關聯性，透過振動量測找尋一與加工件表面粗糙度為正相關之切削品質指標，並以其預估當前工件品質的優劣。透過切削鋁合金與中碳鋼的實驗與分析，本研究提出兩個與粗糙度均為高度相關之切削品質指標，其一為主軸與平台間的振動傳遞率；其二為主軸傳遞至平台的振動量大小。
有了能間接代表加工件表面粗糙度的指標之後，本論文希望透過此指標來找尋較佳之進給速度，一般而言，維繫刀具的壽命為決定進給速度的主要依據，而所謂最佳進給速度即是犧牲些微切削品質，但卻能大幅提升切削效率，抑或是降低些微切削效率，但卻能獲得較佳之切削品質，甚至是大於刀具廠商推薦之進給速度，但卻能擁有相對較佳之切削品質。根據本論文之研究結果，透過有考慮機台動態特性之切削品質指標，可以有效改善切削效率。

關鍵字

切削品質指標 ； 表面粗糙度 ； 振動傳遞率 ； 振動 ； 進給速度

並列摘要

The relationship between machining vibration and work piece surface roughness is investigated for a machine tool in operation. The purpose is to determine a machining quality index based on machine tool vibration that is positively correlated with the surface roughness. Then this machining quality index can be used as an indicator that indirectly represents the surface roughness. Several vibration quantities are studied and results from experiments of machining aluminum and medium-carbon steel show that two quantities are correlated well to the surface roughness. One is the vibration transmissibility between the spindle and the worktable; and the other is the vibration amplitude transmitted from the spindle to the worktable.
With this machining quality index that indirectly represents the surface roughness of work piece, a methodology in determining the optimal feed rate is proposed. Traditionally, the tool life is the main factor while the tool manufacturer determines the feed rate. As an optimal feed rate, it refers to following cases: sacrificing slight quality, but it can significantly improve the cutting efficiency or reducing slight cutting efficiency, but it can get better quality, even, the feed rate larger than that recommended by the tool manufacturers but with a smaller value of machining quality index. Experiment results show that the machining efficiency is greatly improved due to this optimal feed rate determined with the machine dynamics taken into consideration.

並列關鍵字

Machining quality index ； Surface roughness ； Vibration transmissibility ； Vibration ； Feed rate

參考文獻

[1]S.A. Tobias, Machine Tool Vibration, Blackie, London, 1965.

[3]S.S. Abuthakeer, P.V. Mohanram and G. Mohankumar, “The effect of spindle vibration on surface roughness of work piece in dry turning using artificial neural networks,” International Journal of Lean Thinking, pp. 1-16, 2011.

[4]B. Yegnanarayana, Artificial neural networks, PHI Learning Pvt. Ltd, 2009.

[5]陳傑，工具機預估工件銑削品質可行性之研究，國立中正大學機械工程研究所碩士論文，2014。

[6]M. Kuttolamadom, S. Hamzehlouia and L. Mears, “Effect of machining feed on surface roughness in cutting 6061 aluminum,” SAE International Journal of Materials and Manufacturing, vol. 3, no. 1, pp. 108-119, 2010.