Perfect Countermeasure against Pattern Formation Phenomena Generated in Contact Rotating Systems

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This investigation deals with a countermeasure by using dynamic absorbers for polygonal wear of work rolls in a hot leveler of steel making machine and proposes the optimal design method of dynamic absorbers. In the case of the actual machine in which the contact rigidity between rolls and plate is comparatively soft, it was shown that the polygonal wear phenomena were all perfectly suppressed by two dynamic absorbers. An experimental equipment of a single degree-of-freedom pattern formation system with a pair of contact rotating rolls and a dynamic absorber are made. According to the results of the experiments without dynamic absorber, it is confirmed that the relation among the natural frequency of the system, the polygonal number and the rotating speed agree with the analytical results qualitatively. According to the results of the experiments using a damped dynamic absorber, the delaying effect of pattern formation is confirmed. Also, a good quantitative agreement between the exper … More imental and analytical results is confirmed. Moreover, it is confirmed that damping of a dynamic absorber is necessary to delay pattern formation phenomena.Next we deals with a countermeasure against pattern formation phenomena generated on film winder using dynamic absorbers. Pattern formation phenomena of the wound sheet sometimes occur in operation because of the viscoelastic characteristics of the film. The pattern formation phenomena lead to a fatal damage on the film. We conducted experiment to generate the pattern formation using experimental apparatus, and theoretically analyzed to clarify the mechanism of the pattern formation phenomena considering the elastic deformation of the rolls. They also theoretically examined the countermeasure to suppress the phenomena by attaching some dynamic absorbers. The effectiveness of the tunable dynamic absorbers was confirmed by the theoretical analysis.The pattern formation phenomena, namely, rifling marks in the BTA deep hole cutting process were treated experimentally and analytically. It was shown that the optimal angles among cutting edge and guides exited and the rifling marks were not generated for the optimally designed BTA. Less