Minimization of torsion vibrations at deep-drilling tools through glued joints with defined damping

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Gun drilling is a deep hole drilling method often used owing to the attainable machining quality. Torsional vibrations, limiting the productivity of the process, may however arise especially at high feed rates due to the slim geometry of the tools. Hence, the development of suitable dampers is still being worked on to increase the productivity of the process. Previous developments, however, could not gain acceptance on the market. The reasons for that are, among other things, the limited effectiveness of some dampers or in the case of controlled systems, their high costs as well as their complexity.Preliminary tests showed that bonded instead of soldered interfaces between the clamping sleeve and the shank of the tool may have a damping and therefore positive influence on the dynamic stability of the tool. The aim of this project is to systematically assess the static and dynamic behaviour of bonded gun drilling tools and their effects on the drilling process as well as the resulting machining quality. Another aim is to create a finite elements model of the bonded tools for examining and predicting the damping and its effects on the process, depending on the characteristics of the adhesive as well as the thickness of the adhesive layer. In addition, the damping mechanisms occurring for different types and kinds of adhesives will be identified to facilitate a specific optimisation. Altogether five different adhesives (anaerobic adhesive, one-component as well as two-component epoxy resin adhesives) by different manufacturers will be used for this.