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1

An experimental study on the determination of optimal lubrication conditions in a high-speed spindle

Park S.-J., Hwang Y.-K, Lee C.-M

Journal of Machine Engineering

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2009

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Vol. 9, No. 2

106--113

EN

The heat generation inside spindles becomes a major factor that limits the allowable maximum rotational speed in machine tools and decreases the cutting quality. It is necessary to accurately estimate the temperature distribution in spindles caused by the heat generation in bearings and its heat transfer characteristics in order to perform the high-speed and high-precision in high-speed spindles. In addition, an accurate correction process is required according to the results of the estimation through investigating the thermal deformation error. A commercial program, MINITAB, was used to establish an experiment plan that analyzes the heat generation characteristics of the spindle system according to the operation and lubrication conditions of the spindle. Also, the change in the outer ring temperature of bearings was measured according to the experimental plan. After establishing a response surface model using the results of the experiment, the estimation equation of the quadratic polynomial model was proposed for determining the optimal lubrication condition. A verification experiment was applied to verify the accuracy of the experimental equation determined by the estimated regression model and the experimental value used in the estimation of the regression model.

2

Analiza błędnych ruchów wrzecion szybkoobrotowych

Jemielniak K.

Archiwum Technologii Maszyn i Automatyzacji

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2004

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Vol. 24, nr 2 sp

67-74

PL

Na dokładność obróbki wpływa nie tylko dokładność geometryczna, lecz również błędne ruchy wrzeciona obrabiarki w czasie obróbki. Odgrywają one szczególnie ważną rolę w przypadku obróbki z dużą prędkością obrotową. Tymczasem w krajowej praktyce, zgodnie z normami, badania dokładności geometrycznej są ograniczone do badań statycznych (przy nieruchomym wrzecionie lub przy wolnych obrotach). W artykule przedstawiono metodykę wyznaczania błędnych ruchów wrzecion szybkoobrotowych w czasie wysokich obrotów na podstawie pomiarów czujnikami bezdotykowymi odchyleń wrzeciona lub zamocowanego w nim trzpienia od ustalonego położenia. Istotną rolę w tej metodyce odgrywa wyróżnienie kierunków wrażliwych (mających wpływ na dokładność) i niewrażliwych oraz rozkład całkowitych błędnych ruchów promieniowych na synchroniczne i asynchroniczne.

EN

Machining accuracy depends not only on geometric accuracy but also on machine tool spindle error motions during machining. This is particularly important in machining with high rotational speed. Nevertheless in Polish practice, accordingly to the Polish standards, investigation geometric accuracy, are limited to static tests (standing or slowly moving spindle). Paper presents procedure of evaluation of high speed spindle error motions based on measurements of radial movements of the spindle or a target mounted in spindle using non-contact sensors. Important role in presented procedure plays distinction of sensitive (influencing accuracy) and not sensitive directions and distribution of total radial errors to synchronous and asynchronous.

3

Reliable high speed spindles by optimum bearings preload

Hagiu G.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no 1

57-70

EN

To design a high speed spindle with enhanced qualitative performances - high accuracy and service life together with a stable dynamic and thermal regime - two main conditions have to be secured: an optimum internal load distribution on the bearings and an efficient and safe lubrication regime. The preload force, by the significant changes produced on the bearings functioning parameters, i.e., kinematics, both load internal distribution and amount, appears as one of the most important factors affecting the main reliability parameters of high speed spindles. A theoretical research assisted by an experimental validation on grinding machine spindles was developed to determine the bearings preload influence on the spindles main reliability parameters, i.e., service life, dynamic and thermal stability. From the analysis of the results obtained, the optimum bearings preloads able to secure, in given operating conditions, the imposed reliability parameters for the high speed spindles were determined.