Vibration energy dissipation of rotating cutting tool holders with applied particle dampers

Abstract Milling, especially of lightweight components, but also of geometrically complex functional parts, often requires the use of long-overhanging cutting tool systems. This, as well as the interrupted cut, often causes significant tool vibrations. These not only considerably reduce tool life, but can also lead to increased surface roughness or even substantial workpiece damage. The use of damped cutting tool holders significantly increases process stability and ensures reliable machining operations even at elevated parameters. In this context, the use of particle dampers, in which vibration energy is dissipated due to inelastic particle collisions and friction processes, have been fundamentally proven in recent investigations with rotating tool systems. The use of additive manufacturing processes, such as Laser Powder Bed Fusion (LPBF), enables the application of complex designed particle dampers close to the working zone. However, a process-specific modification is further possible applying selected filling particles. The investigations presented in this paper focus on analyzing the influence of additional internal structures integrated into the segmented cavities of HSK63 cutting tool holders on the dissipation capacity. In particular, a specially developed analogy test setup is used to demonstrate that the internal structure improves inhomogeneous particle distribution within the cavity segments due to the centripetal force that occurs during rotation. In addition, the additional contact surfaces resulting from the internal structure have a positive effect on the dissipation mechanisms. Another major part of the investigations is to develop an innovative strategy for the additive manufacturing of ball masses within the applied lattice structure. Thus, the dissipation potential could be further increased due to the higher masses of the individual particles in conjunction with the lattice structure. This structure prevents severe inhomogeneities resulting from centripetal force by allowing a defined motion range corresponding to the particle size. Comprehensive analogy tests demonstrate that this innovative particle damper design can enable broadband damping performance that considerably exceeds the dissipation potential of conventionally designed particle dampers.