Development of damped tool holders for long cantilever, rotating tools

During the cutting process the tool holder, being the interface between tool and spindle, has a high impact of the process quality. Particularly for long tools the dynamic properties of the tool holder have a strong impact on the process quality. Long tools are necessary to machine deep pockets and holes as well as complex structures. Due to the high length-to-diameter-ratio unstable process behavior occurs even at low cutting depths. The consequence of unstable processes is an increase of tool wear and scrap parts. To avoid unstable process behavior the material removal rate and the therefore the productivity must be decreased. The increase the dynamic stiffness, existing damped tool holder damp tool vibration using absorbers. However, two new natural frequencies occur.

Furthermore, the effect of the absorber is just at one frequency optimal. If the tool is detuned by replacing the cutting tool, the damping effect decreases.

The research project deals with the development and investigation of a new damped tool holder based on friction damping. The aim is to increase the damping and stiffness as well as the resulting productivity of the tool holder compared to existing tool holder for a wide frequency range.