The superior properties of CFRPs on the other side pose a great challenge for tool manufacturers

The superior properties of CFRPs on the other side pose a great challenge for tool manufacturers. As the characteristics of CFRP materials can vary widely due to different compositions of e.g. fibre types, diameters, lengths and orientations as well as the synthetic matrix specification, they show also a diverse behavior during machining. Therefore it is often necessary to develop application related cutting tools in order to meet the different requirements that come along with variable workpiece properties. Hence, during machining of CFRPs versatile machining errors like delamination, fraying, fibre fracture, burr formation and burn can be observed. Currently polycrystalline diamond (PCD) and diamond coated cemented carbide tools are widely used.

 
There are some specific requirements regarding the tool design and the cutting material that should be met by all used tools. In terms of the tool design, it was investigated, that sharp cutting edges with a low cutting edge radius and chipping are necessary in order to realize a cutting of the fibres and prevent machining errors. Another important tool feature with influence on the cutting process is the surface quality of the rake face. It was observed, that the surface quality can influence the adhesion tendency and the coating process significantly [12,13]. Regarding the cutting material a certain resistance against abrasive wear is essential to ensure an economical application of cutting tools. In recent research activities at the Institute for Machine Tools and Factory Management (IWF) different approaches were pursued in order to improve the machining behavior of CFRP cutting tools. In the following, two of them will be described in detail.