Design and optimized analysis of high speed precise machine tool spindles

Upcoming machine tools need to be extremely efficient systems to maintain the needed intellectual performance and stability. The spindle tool system is necessary to optimize which enhances the rigidity of the spindle and in turn produces the cutting stability with higher productivity. Prediction of the dynamic behavior at spindle tool tip is therefore an important criterion for assessing the machining stability of a machine tool at design stage. In this work, a realistic dynamic high-speed spindle /milling tool holder/ tool system model is elaborated on the basis of rotor dynamics predictions. The integrated spindle tool system in analyzed with the Timoshenko beam theory by including the effects of shear and rotary deformation effects. Using the frequency response at the tool tip the corresponding stability lobe diagrams are plotted for the vertical end mill system. Furthermore an optimization study is carried out at design stage for the bearing system and the rotor positions for maximizing the chatter vibration free cutting operation at the desired depth of cuts with precise rotational speeds.It is markedly found that the first mode of vibration had a large impact on the dynamic stability of the system. The parametric studies are conducted such as tool overhang and bearing span and the influence of these on the system dynamics are identified and the corresponding stability lobe diagrams are plotted. It is evidently found that the second mode of the frequency response has critically affected the bearing span and competing lobes are identified. These results are assisted to design a spindle bearing system at the desired machining conditions. A neural network based observer is designed based on the simulation resultsto predict optimum design parameter values.

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Effect of a Nonlinear Joint on the Dynamic Performance of a Machine Tool

Journal of Manufacturing Science and Engineering ◽

10.1115/1.2752830 ◽

2007 ◽

Vol 129 (5) ◽

pp. 943-950 ◽

Cited By ~ 31

Author(s):

Jaspreet S. Dhupia ◽

Bartosz Powalka ◽

A. Galip Ulsoy ◽

Reuven Katz

Keyword(s):

Machine Tool ◽

Frequency Response ◽

Response Function ◽

Frequency Response Function ◽

Dynamic Performance ◽

Stability Lobe ◽

Receptance Coupling ◽

Nonlinear Joint ◽

Stability Lobe Diagrams ◽

Machine Structure

This paper presents the effect of experimentally evaluated nonlinearities in a machine joint on the overall machine tool dynamic performance using frequency response functions and stability lobe diagrams. Typical machine joints are very stiff and have weak nonlinearities. The experimental evaluation of the nonlinear joint parameters of a commercial translational guide has been discussed in Dhupia et al., 2007, J. Vibr. Control, accepted. Those results are used in the current paper to represent the connection between the column and the spindle of an idealized column-spindle machine structure. The goal is to isolate and understand the effects of such joints on the machine tool dynamic performance. The nonlinear receptance coupling approach is used to evaluate the frequency response function, which is then used to evaluate the stability lobe diagrams for an idealized machine structure. Despite the weak nonlinearities in the joint, significant shifts in the natural frequency and amplitudes at resonance can be observed at different forcing amplitudes. These changes in the structural dynamics, in turn, can lead to significant changes in the location of chatter stability lobes with respect to spindle speed. These variations in frequency response function and stability lobe diagram of machine tools due to nonlinearities in the structure are qualitatively verified by conducting impact hammer tests at different force amplitudes on a machine tool.

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Interactive Design-Assistance System of Machine Tool Structure in Conceptual and Fundamental Design Stage

International Journal of Automation Technology ◽

10.20965/ijat.2010.p0303 ◽

2010 ◽

Vol 4 (3) ◽

pp. 303-311 ◽

Cited By ~ 16

Author(s):

Zhangyong Yu ◽

◽

Keiichi Nakamoto ◽

Tohru Ishida ◽

Yoshimi Takeuchi

Keyword(s):

Machine Tool ◽

Beam Theory ◽

Interactive Design ◽

Assistance System ◽

Design Stage ◽

Beam Structure ◽

Actual Structure ◽

Machine Tool Structure ◽

Short Time ◽

Fundamental Design

This paper presents the development of an interactive design-assistance system for quickly determining a machine tool structure in conceptual and fundamental design stage. The distinguishing point in this system is that all components of one machine tool structure are approximated into conceptual beams. Therefore, by using the interactive design-assistance system, designers can decide a beam structure in a short time because classical beam theory makes it easy to analyze the static, dynamic and thermal stiffness. Converting the beam structure to an actual structure, designers can complete the conceptual and fundamental design of a machine tool structure. Consequently, the interactive design-assistance system enables designers to complete structural design of a machine tool in a shorter time with higher efficiency.

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An application of Taguchi method on the high-speed motorized spindle system design

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406211405279 ◽

2011 ◽

Vol 225 (9) ◽

pp. 2198-2205 ◽

Cited By ~ 8

Author(s):

C-W Lin

Keyword(s):

Optimal Design ◽

Taguchi Method ◽

Machine Tool ◽

High Speed ◽

Signal To Noise Ratio ◽

Design Stage ◽

Original Design ◽

Spindle System ◽

Design Engineers ◽

Design Variables

As spindle speeds increase, the variations caused by high-speed effects become more significant. Therefore, in the initial design stage, it is necessary for machine tool design engineers to construct a robust high-speed machine tool that possesses high first-mode natural frequencies (FMNFs) and is insensitive to high operating speeds. In this article, Taguchi method is used to identify the optimal values of design variables (DVs) for a robust high-speed spindle system with respect to the signal-to-noise ratio (SNR) of system FMNF. The L18 orthogonal array covers seven main DVs at three levels each, one main DV at two levels, and the noise factor spindle speeds at six levels. The results show that the new optimal design has improved the SNR of the FMNF by 2.06 dB from the original design; this implies that the quality loss has been reduced to 62 per cent of its original value. The optimal design has been verified by a confirmation numerical experiment.

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Dynamic Stability of a Motorized High Speed Machine Tool Spindle Supported on Bearings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.612.29 ◽

2014 ◽

Vol 612 ◽

pp. 29-34

Author(s):

Jakeer Hussain Shaik ◽

J. Srinivas

Keyword(s):

Machine Tool ◽

Frequency Response ◽

High Speed ◽

Stability Boundary ◽

Second Phase ◽

Element Formulation ◽

Machining Parameters ◽

Response Functions ◽

Frequency Response Functions ◽

The Stability

Dynamic behaviour of spindle system influences chatter stability of machine tool considerably. Self-excited vibrations of the tool results in unstable cutting process which leads to the chatter on the work surface and it reduces the productivity. In this paper, a system of coupled spindle bearing system is employed by considering the angular contact ball bearing forces on stability of machining. Using Timoshenko beam element formulation, the spindle unit is analyzed by including the gyroscopic and centrifugal terms. Frequency response functions at the tool-tip are obtained from the dynamic spindle model. In the second phase, solid model of the system is developed and its dynamic response is obtained from three dimensional finite element analysis. The works on analysis of the stability of milling processes focus on calculating the stability boundary of the machining parameters based on the dynamic models characterizing the milling processes. The stability lobe diagrams are generated from frequency response functions (FRF’s) lead to an stability limit prediction for the system at high speed ranges.

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Frequency response function simulation and evaluating in boring

Mechanics and Advanced Technologies ◽

10.20535/2521-1943.2021.5.3.242214 ◽

2021 ◽

Vol 5 (3) ◽

Author(s):

Maksym Shykhalieiev ◽

Vadim Medvedev

Keyword(s):

Frequency Response ◽

Response Function ◽

Phase Angle ◽

Frequency Response Function ◽

Dynamic Stiffness ◽

Stability Lobe ◽

Machining Center ◽

Machining System ◽

Computer Numerical Simulation ◽

Stability Lobe Diagrams

Finite element method of simulating frequency response function (FRF) for boring tool in LS-Dyna solver is investigated in this work. Nowadays, computer numerical simulation allows to obtain FRF using different materials model with high precision compared to real experiments with sensors like impact hammer testing. This function is used in construction of stability lobe diagrams that allows operator of machining center to avoid chatter self-excited vibrations. Such vibration is led to decreasing of productivity and quality in cutting of metals and other materials. Amplitude and phase angle for the model is obtained from LS-Dyna result interpreter, that reads binary files, created during simulation by the program. Amplitude and phase angle of frequency response function are depending on dynamic stiffness of machining system. Real and imaginary part of frequency response function have been obtained during simulation. With luck of dynamic stiffness amplitudes of response increases.

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Machine Bed Support with Sliding Surface for Improving the Motion Accuracy

International Journal of Automation Technology ◽

10.20965/ijat.2016.p0447 ◽

2016 ◽

Vol 10 (3) ◽

pp. 447-454 ◽

Cited By ~ 1

Author(s):

Yusaku Shirahama ◽

◽

Ryuta Sato ◽

Yusuke Takasuka ◽

Hidenori Nakatsuji ◽

...

Keyword(s):

Mathematical Model ◽

Machine Tool ◽

Frequency Response ◽

High Speed ◽

Numerical Control ◽

Sliding Surface ◽

Response Curves ◽

Support Mechanism ◽

Speed Tracking ◽

The Mathematical Model

The purpose of this study is to develop a new machine bed support mechanism for reducing the vibration generated during the high-speed tracking motion of numerical control machine tools. In order to achieve this, the frequency response and motion trajectory of a machine tool with the proposed machine bed, which has a sliding surface, are measured and compared with that of the conventional support. Based on the modal analysis of the machine tool structure, a mathematical model representing the influence of the machine bed characteristics on the vibration is also developed. The model consists of a bed, saddle, table, column, and spindle head. Every component has three degrees of freedom for each of the translational and rotational axes. In order to evaluate the characteristics of the machine bed, the mathematical model determines the stiffness and damping along the X-, Y-, and Z-axis between the bed and the ground. The frequency response curves simulated by using the mathematical model are compared with that of the measured ones. From the results of the experiments and simulations, it is confirmed that the vibration generated during high-speed tracking motions can be reduced by using the proposed machine bed with a sliding surface.

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Prediction of Stability Lobe Diagrams in High-Speed Milling by Operational Modal Analysis

Procedia Manufacturing ◽

10.1016/j.promfg.2020.05.049 ◽

2020 ◽

Vol 48 ◽

pp. 283-293

Author(s):

Vineet Paliwal ◽

N. Ramesh Babu

Keyword(s):

Modal Analysis ◽

High Speed ◽

Operational Modal Analysis ◽

High Speed Milling ◽

Stability Lobe ◽

Stability Lobe Diagrams

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Effective Rotordynamics Analysis of High Speed Machine Tool Spindle – Bearing System

Materials Today Proceedings ◽

10.1016/j.matpr.2021.05.359 ◽

2021 ◽

Author(s):

S.B. Murgayya ◽

H.N. Suresh ◽

N. Madhusudhan ◽

D. SarvanaBhavan

Keyword(s):

Machine Tool ◽

High Speed ◽

Spindle Bearing ◽

Machine Tool Spindle ◽

High Speed Machine ◽

Bearing System

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Receptance Coupling Study of Tool-Length Dependent Dynamic Absorber Effect

Manufacturing Engineering and Materials Handling Engineering ◽

10.1115/imece2004-60081 ◽

2004 ◽

Cited By ~ 2

Author(s):

Timothy J. Burns ◽

Tony L. Schmitz

Keyword(s):

Frequency Response ◽

High Speed ◽

Removal Rate ◽

Stability Lobe ◽

Receptance Coupling ◽

Rapid Prediction ◽

Substructure Analysis ◽

Dynamic Absorber ◽

Receptance Coupling Substructure Analysis ◽

Free Material

The chatter-free material removal rate during high-speed machining of aluminum using long, slender endmills is limited by the cutting system dynamics, which changes with the tool length. Traditional stability-lobe diagrams that predict the maximum allowable chip width for a given spindle speed are determined using the tool point frequency response function. A brief review is given of a combined analytical and experimental method that uses receptance coupling substructure analysis (RCSA) for the rapid prediction of the tool-point frequency response as the tool length is varied. The basic idea of the method is to combine the measured direct displacement vs. force receptance (i.e., frequency response) at the free end of the spindle-holder system with analytical expressions for the tool receptances. The method is then used to provide an explanation for the dynamic absorber effect that has been observed in the context of tool-length tuning.

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