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Analytical and Experimental Modeling and Predicting Chatter Occurrence during Thin-walled Parts Milling

Sotoudeh, Mahsa | 2014

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45690 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Movahhedy, Mohammad Reza
  7. Abstract:
  8. Milling of thin-walled parts is a widely used process in aeronautical and automotive industries. Along the milling of these low rigidity parts, large quantities of material are removed using high removal rate conditions with the risk of the instability of the process as the result of chatter vibration. Self-excited chatter vibration is an undesirable phenomenon in all machining processes and many efforts have been made in order to understand its mechanism and deal with its destructive effects. Studying chatter in machining processes with variable dynamics, which this thesis represents an instance of it, has been taken into consideration in the recent years. Most of researches done in this area, model process dynamics by considering only the machine or workpiece dynamics and a few of them consider the dynamics of the both subsystems simultaneously. This thesis, studies the effect of cutting conditions and different strategies used in the milling of thin walls by considering the part variable dynamics during the process and using relative transfer function for modeling system dynamics in the stages that two subsystems have similar dynamic behavior. Results of these studies show the continuous change of the process stability boundaries due to changes in the workpiece dynamics behavior, importance of paying attention to the workpiece dynamics and its changes during different machining conditions and strategies and using it in order to increase the stable material removal rate. Determining stability limits of radial depth of cut unlike the common milling SLDs which show the stability limits of axial depth of cut and approximating minimum initial thickness of the wall for its stable milling process independent of spindle speed are also done in this thesis. Finally, results obtained from the modeling of the process have been validated by a series of machining tests
  9. Keywords:
  10. Stability Lobe ; Milling Thin-Walled Parts ; Chatter Stability ; Part Dynamics

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