High Performance Machining of Profiled Slots in Nickel-Based-Superalloys

Broaches made of high speed steel (HSS) are state of the art for the production of complex slots in turbine discs, but they are increasingly reaching their limits in machining difficult to machine materials. The application of carbide as cutting material is a very promising approach for broaching tools and could have a significant impact on productivity. In this case, the lower fracture toughness of cemented carbide compared to high speed steel is a challenge. One effect is increased chipping of the cutting edge. Therefore, in the following paper, the influences of the carbide grade as well as the tool micro and macro geometry and cutting parameters on tool life were investigated. An analogy test set up was applied that allows a free orthogonal cut with a single cutting edge. Finally, a comparison between the productivity of HSS broaching, cemented carbide broaching and trochoidal milling was drawn.