Modelling the Geometrical Accuracy for Different Part Geometries and Process Parameters when Broaching Fir-Tree Slots in Turbine Disks

Procedia CIRP, vol. 102, pp. 31–36

Abstract

Constructive measures in the design of aircraft engines aiming for CO2 and NOx emission reduction result in miniaturization of the components, e.g. the rotating turbine disks. The resulting filigree structures determine a reduction of the resistance against elastic workpiece deformations during the machining process. This leads to increasing demands on the cutting process to maintain the required form and position tolerances. In turbine disks, fir-tree slots as the fixing for the turbine blades are classified as safety-critical components. Currently, the profiled slots are manufactured by broaching. In order to guarantee the required component quality of the resulting fir-tree structure, it is necessary to examine the tool design systematically. By using FE simulations, it is possible to predict geometrical deviations after broaching and to perform counter measurements in tool design. In this paper, an innovative approach is presented, which combines an empirical-analytical cutting force model and numerical FE simulations to model the elastic deformations during the cutting process. Therefore, empirical cutting force information are used as input data for the dynamic FE simulations. The results are then analyzed regarding the achievable form and position tolerances when broaching profile grooves. This paper presents a parameter study on workpiece and process parameters and an evaluation of their impact regarding the geometrical accuracy in broaching.

Authors 4

1. Tobias Seelbach corresponding Aachen Laboratory for Machine Tools and Production Engineering WZL

   RWTH Aachen University

   Affiliation as printed

   Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University. Campus-Boulevard 30, 52074 Aachen, Germany

2. L. Beja Aachen Laboratory for Machine Tools and Production Engineering WZL

   RWTH Aachen University

   Affiliation as printed

   Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University. Campus-Boulevard 30, 52074 Aachen, Germany

3. Daniel Schraknepper Aachen Laboratory for Machine Tools and Production Engineering WZL

   RWTH Aachen University

   Affiliation as printed

   Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University. Campus-Boulevard 30, 52074 Aachen, Germany

4. Thomas Bergs Aachen Fraunhofer IPT Laboratory for Machine Tools and Production Engineering WZL

   Fraunhofer Institute for Production Technology IPT · RWTH Aachen University

   Affiliation as printed

   Fraunhofer IPT, Steinbachstraße 17, 52074 Aachen, Germany

   Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University. Campus-Boulevard 30, 52074 Aachen, Germany