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MODELLING AND SIMULATION OF A NEW VARIABLE STIFFNESS HOLDER FOR MILLING OF FLEXIBLE DETAILS

Abstract

Modern industry expectations in terms of milling operations often demand the milling of the flexible details by using slender ball-end tools. This is a difficult task because of possible vibration occurrence. Due to existence of certain conditions (small depths of cutting, regeneration phenomena), cutting process may become unstable and self-excited chatter vibration may appear. Frequency of the chatter vibration is close to dominant natural frequency of the workpiece or the tool. One of the methods of chatter vibration avoidance is matching the spindle speed to the optimum phase shift between subsequent cutting edges passes (i.e. the Liao-Young condition). However, the set of optimum spindle speeds from the point of view of vibration reduction may be not optimum one from other points of view. For example milling efficiency or machine tool capabilities cannot be assured. This article presents the idea of a workpiece holder with adjustable stiffness and discusses a new variant of its realization. In the holder, milling process is performed at constant spindle speed and feed speed. In order to avoid vibration the holder stiffness is modified. Stiffness changes modify natural frequencies of the workpiece and thus it is possible to modify dynamic properties of the workpiece in such a way that arbitrary chosen, constant spindle speed will be optimum, due to the Liao-Young condition performance. Calculation of the optimum stiffness is performed before milling, based on the workpieces modal identification results and the finite element model simulations.

Keywords:

milling, vibration reduction, optimum spindle speed, optimum stiffness

Details

Issue
Vol. 24 No. S1(93) (2017)
Section
Latest Articles
Published
23-05-2017
DOI:
https://doi.org/10.1515/pomr-2017-0029
Licencja:
Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Open Access License

This journal provides immediate open access to its content under the Creative Commons BY 4.0 license. Authors who publish with this journal retain all copyrights and agree to the terms of the CC BY 4.0 license.

 

Author Biographies

Marek A. Galewski,
Gdańsk University of Technology, Faculty of Mechanical Engineering



Michał Mazur,
Gdańsk University of Technology, Faculty of Mechanical Engineering



Marek Chodnicki,
Gdańsk University of Technology, Faculty of Mechanical Engineering



Authors

  • Krzysztof J. Kaliński

    Gdańsk University of Technology, Faculty of Mechanical Engineering
  • Marek A. Galewski

    Gdańsk University of Technology, Faculty of Mechanical Engineering
  • Michał Mazur

    Gdańsk University of Technology, Faculty of Mechanical Engineering
  • Marek Chodnicki

    Gdańsk University of Technology, Faculty of Mechanical Engineering

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