Among the different working strategies for ‘high performance cutting’ (HPC), trochoidal milling is an efficient way of processing (difficult materials), and is one that also utilizes a longer cutting edge. In order to increase productivity even further, (i.e. reducing the cycle times) the materials and processes laboratory at University of Karlsruhe has developed another strategy for trochoidal cutting, namely epicycloidal cutting.

The difference between the trochoidal and the epicycloidal tool path is illustrated in the figures below. The red circle represents the cutting. The blue line is the centre point of the cutter.

With epicycloidal cutting, the tool path consists of a main arc and a side arc.

In order to compare both methods, three criteria were evaluated during tests: cutting power, vibration and tool life. The most significant results were as follows:

• The cutting power and vibration levels were approximately 10 % higher with the epicycloidal method in comparison with the trochoidal method.
• The processing time was up to 20 % lower with the epicycloidal method (depending on the processing parameters), which is certainly of interest for coarse processing.

Further research will be carried out into the extent to which the increased cutting and vibration levels negatively affect tool life.

Source

• Epicycloidal versus trochoidal milling - Comparison of cutting force, tool tip vibration, and machining cycle time, M. Salehi, M. Blum, B. Fath, T. Akyol, R. Haas, J. Ovtcharova, 7th HPC 2016 - CIRP Conference on High Performance Cutting