Flank milling model for tool path programming of turbine blisks and compressors

Abstract

In this paper, a methodology for complex surface machining based on cutting forces prediction is presented. The work is focused on blade finishing operations. The cutting forces model developed can be applied to three axis and five axis milling cases. For three-axis cases, the chip thickness is calculated according to traditional analytical methods. On the contrary, for five-axis cases the chip thickness is obtained from a geometric method developed in the paper. The cutting forces values can be calculated for the complete toolpath, but the presented model can also provide the programmer information about the cutting forces in a single point of the toolpath. The cutting force model is integrated in the CAM software in order to provide an extra tool that helps the programmer to decide which the optimal milling strategy is, based on the minimum cutting forces. In the last section, results of a case study based on impeller and blisk blades flank milling are discussed. Model predicted forces and real measured forces of flank milling operations are compared for model validation. Applying this methodology, cutting forces can be taken into account as a decisive criterion for optimal tool path selection.

Keywords:

• cutting forces
• blisk
• impeller
• flank milling
• tapered ball nose end mill cutter

Acknowledgements

Thanks are addressed to the Department of Education, Universities and Research of the Basque Government for their financial support. Special thanks are addressed to the Basque Government for the support on the Paint project. We thank also the UFI in Mechanical Engineering of the UPV/EHU for its support to this Project.