Suppression of tool tip FRF in machine tool assemblies by component mode tuning method

Date

2020-9

Author

Karataş, Gamze

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Chatter is a major problem in machining processes resulting in high amplitude vibrations and noise, poor surface finish, decreased life of the tool and mechanical components, thus limited productivity. Chatter stability of a machining process can be altered by modifying the tool tip frequency response function (FRF) of the machine tool assembly. Tool tip FRF of the machine tool assembly can be suppressed by creating tuned mass damper (TMD) effect among assembly components. In some milling applications, a holder extension can be added between the holder and the tool to increase the overall effective length for reaching far sections of a workpiece. In this thesis, an analytical design optimization procedure is presented to damp the most flexible mode of the spindle assembly by tuning the dimensions of the holder extension and the tool. As the first approach, the length of the holder extension is optimized to create modal interaction which suppresses the peak tool tip FRF. Then, both holder extension length and tool overhang length are optimized simultaneously to further increase the dynamic rigidity as a result of TMD effect. Additionally, the profile of the holder extension and the overhang length of the tool are tuned simultaneously to maximize the reduction in the peak tool tip FRF. Substantial improvements in tool tip FRF and chatter-free material removal rate (MRR) are demonstrated through simulations. The results show that, there is a great potential for increased machining productivity caused by suppressed dominant mode of the assembly by tuning the dimensions of the holder extension length and the overhang tool length simultaneously creating maximized TMD effect.

Subject Keywords

Chatter stability, Machine Tool Dynamics, FRF Modification, Tuned Mass Damper Effect, Design Optimization, Tırlama Kararlılığı, Tezgah Dinamiği, FRF Modifikasyonu, Ayarlı Kütle Sönümleyici Etki, Tasarım Optimizasyonu

URI

https://hdl.handle.net/11511/104875

Collections

Graduate School of Natural and Applied Sciences, Thesis