Investigations of Burr Formation in Single Point Planing with Varying Uncut Chip Thickness

The main loss mechanism in dry-running vacuum pumps is the clearance flow between the rotor and the housing, which can be reduced by introducing sawtooth structures transverse to the direction of flow. Due to the small geometric dimensions of the structures and the varying uncut chip thickness during machining, promoting burr formation, achieving the required shape accuracy is a challenging task. Especially, the formation of burrs during machining the final rotor surface often poses problems. To address this challenge, experimental and simulative investigations are conducted, aiming to develop a 3D coupled Eulerian-Lagrangian chip formation simulation capable of predicting the burr geometry. Furthermore, a new analytical model for orthogonal cutting considering the geometry of a triangle insert with a corner radius is developed to enhance the understanding of the cutting process and provide a rapid validation tool for future investigations. Based on these results, optimized tool geometries are derived and tested simulatively showing great potential.