Frequency Domain Study of Vibrations above and under Stability Lobes in Machining Systems
2014 (English)In: Procedia CIRP, E-ISSN 2212-8271, Vol. 14, p. 164-169Article in journal (Refereed) Published
Abstract [en]
Using modified Nyquist contours, the dominant poles of the closed loop delay-differential equation for machining systems such as milling are identified. Contours with constant damping ratio of the dominant poles are constructed using this method. These contours are similar in shape to the stability lobes, but move upwards and to the right as the instability parameter increases. Additionally, it is possible to study the movement of the dominant poles to the right-hand side of the complex plane as the system becomes unstable by increasing the depth of cut at a constant spindle speed. The movement of the dominant pole is shown to be towards the right (unstable) and upward (higher vibration frequency) of the complex plane. In some cases, there would be a jump of vibration frequency due to the change of the lobe number. It is also shown that the damping ratio of the structure strongly affects both the vibration frequency and the damping ratio of the dominant poles in the closed loop system. Finally, in two milling experiments with two different spindle speeds and continuously increasing depth of cuts, vibration frequencies are measured and compared to the theoretical predictions. The measurements agree with the theoretical predictions, particularly in the unstable cutting conditions.
Place, publisher, year, edition, pages
Elsevier, 2014. Vol. 14, p. 164-169
Keywords [en]
Stability Chart, Chatter, Nyquist Stability Criterion, Vibration Frequency, Dominant Poles
National Category
Manufacturing, Surface and Joining Technology Other Mechanical Engineering
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
URN: urn:nbn:se:his:diva-22373DOI: 10.1016/j.procir.2014.03.068ISI: 000345439400029Scopus ID: 2-s2.0-84902475150OAI: oai:DiVA.org:his-22373DiVA, id: diva2:1748893
Conference
6th CIRP International Conference on High Performance Cutting, HPC2014, Univ Calif, Berkeley & Davis Campuses, Berkeley, CA, June 23-25, 2014
Projects
InnKa
Funder
EU, European Research Council
Note
CC BY-NC-ND 3.0
The research presented in this paper has been supported by InnKa project, an ERDF project. The contribution is greatly appreciated.
2023-04-042023-04-042024-09-04Bibliographically approved