Date

2013

Author

Yılmaz, Hasan

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Chatter in high speed machining is an important problem which affects the product quality and the manufacturing time. In order to determine the optimum cutting parameters such as depth of cut, feed rate, spinning speed etc., dynamic characteristics of the spindle-holder-tool assembly should be modeled accurately. To determine optimum depth of cut and operating speed, frequency response function (FRF) of the tool point is required. However, in high speed machining, due to high rotational speeds, dynamic characteristics are affected by the spinning speed of the spindle. In this thesis, in order to include the effect of spinning speed into the dynamic analysis of the assembly, a spinning Timoshenko Beam Model is used. Spindle-holder-tool assembly is considered to be composed of several free-free beams having different cross-sections, which are coupled with each other by utilizing FRF coupling method. In the assembly, bearings are modeled as a spring and damper combination and structural modification method is used to include their effects. The developed method is verified by comparing the results for zero spinning speed and also the results obtained by FEM. Variation of the natural frequencies and FRF of an example spindle-holder-tool assembly for different spinning speeds are obtained. For non-spinning case, tool point FRF of the assembly is also obtained by using Rayleigh-Ritz method and results of which are compared with coupled system solution. Finally, stability lobes are obtained for different spin speeds and the effect of gyroscopic forces are studied.

Subject Keywords

Spinning., Beam dynamics., Chattering control (Control systems)., Rayleigh scattering.

URI

http://etd.lib.metu.edu.tr/upload/12615931/index.pdf
https://hdl.handle.net/11511/22540

Collections

Graduate School of Natural and Applied Sciences, Thesis