Analysis of Dynamic Characteristics and Evaluation of Dynamic Stiffness of a 5-Axis Multi-tasking Machine Tool by using F.E.M and Exciter Test

Abstract

This paper describes a case study on dynamic characteristics analysis and dynamic stiffness evaluation of a 5-axis multi-tasking machine tool of ram-head type. Structural dynamics analysis and evaluation are necessary to machine tool design and development to secure good machine tool performance against tough and harsh machining conditions. Such studies are more important to multi-tasking machine tool since it should be able to do different kinds of machining task as well. In this study, natural frequencies and corresponding vibration modes of the machine tool structure were analyzed by using both F.E.M. modal analysis and impulse hammer test. Furthermore, dynamic stiffness of the machine tool was analyzed by using F.E.M. and was also measured by using a hydraulic exciter test. Both the theoretical analysis and test results showed good agreement with each other. Finally, some discussion and review were made based on the analysis results from the view point of resonant vibration and mode coupled chatter.