At Research & Technology under the umbrella of HANNOVER MESSE 2014, the Karlsruhe Institute of Technology (KIT) will present an innovative lightweight machine-tool stage constructed of a carbon-fibre-reinforced polymer (CFRP).

Dr Jürgen Fleischer from the Karlsruhe Institute of Technology (KIT) and his team have developed a lightweight machine-tool stage which stands out on account of its innovative fillable chambers. The stage consists of a CFRP which, compared with conventional steel and cast material, achieves a much better balance between density and rigidity.

In this way it has been possible to build a lightweight stage which is highly dynamic and at the same time very adaptable in terms of mass and vibration behaviour. By altering the volume of fluid in the built-in chambers it is possible to influence the natural frequency. “Via the addition of mass the machine can be detuned in such a way that it delivers the best possible cutting performance in a given process,” Fleischer explains.

As introduced, so far the modification of a machine’s dynamic behaviour has entailed extensive structural changes resulting in a considerable input of time and money. In addition, such modifications are often limited to selected natural frequencies; variable adjustments are not possible. This new approach is of great significance – not so much in standard applications as in the area of high-performance machining.

“We will set up a test rig with the CFRP stage and demonstrate the function of the chambers live and in action,” Fleischer says.

To demonstrate the stage’s dynamic properties, the KIT will initially deploy water, which can be filled and emptied quickly. The chambers can be filled and emptied independently of each other. The maximum quantity of water corresponds approximately to the empty weight of the CFRP stage. Thanks to the low density of carbon fibre, the weight ratio and the natural-frequency detuning effects are greater than in the case of a comparable steel or cast stage.

The wbk Institute at the KIT has conducted extensive trials in order to demonstrate the feasibility and potential of this new approach. Research will continue in order to identify, qualify and quantify improved simulation models. This will provide the basis for the exact design of the relevant components. In parallel the KIT is working with a German machine tool manufacturer on the practical realization of the new concept.

“We assume that the necessary components will be available on the market in around five years,” Fischer emphasizes. There is likely to be a high level of interest in the CFRP stage – not only during HANNOVER MESSE – especially as German companies are regularly at the forefront of innovation in the mechanical engineering industry.

The next HANNOVER MESSE will run from 7 to 11 April 2014.