In internal turning processes, stability decreases as the length-to-diameter ratio increases, due to vibrations. To enable stable machining even with deep contours, vibration-damping boring bars are used. A distinction can be made between different damping concepts.
Active systems reduce vibrations by generating an anti-phase vibration. However, due to the complex commissioning process and the control technology required, these systems have so far only been of limited use. Passive systems, on the other hand, convert the vibration energy into heat for example, through friction and are already widely used in the manufacturing industry due to their simple application. A disadvantage is their inability to adapt to different process conditions.
This is precisely where ProReib comes in: The goal is to develop a semi-actively damped boring bar whose damping properties can be specifically adapted to changing machining conditions. The underlying working principle is based on friction, which is generated by a relative movement between the friction element and the tool shank of a boring bar, converting vibration energy into heat. By means of an adjustable preload of the friction elements, the frictional force and thus the damping behavior can be targeted and influenced.
The project builds upon previous investigations in which the friction element was identified as the limiting factor. To increase the preload force, the hydro-expansion principle is utilized in ProReib. In this process, a cavity in a metal membrane is filled with hydraulic oil and pressurized. The resulting expansion of the membrane generates the required preload of the friction elements.
The research project "Increasing the process stability of long-overhang turning tools through adaptively adjustable friction components" (ProReib) is funded by the Central Innovation Programme for Medium-Sized Enterprises (ZIM). IFW and Diamond Tooling Systems GmbH would like to thank them for supporting the project.
Contact:
For further information, please contact Adrian Bergmann by telephone on +49 511 762 18294 or by email at adrian.bergmann@ifw.uni-hannover.de.
