Rolls-Royce Deutschland Ltd & Co. Kg

Gregor Riedel

Gregor Kappmeyer

Leping Zhu

Liane Holze

With a method for finish-machining the blade tips of rotor wheels made in BLISK design, the rotor wheel or multi-stage compressor rotor (), is machined&#x2014;blade by blade and stage by stage&#x2014;at the blade tips () by a conical cutter () whose cutting edge () is oriented tangentially to the outside surface of the rotor wheel/compressor rotor and routed on the blade tip essentially along the centerline thereof, with the cutting force being introduced perpendicular to the tool axis and in the stiffest direction of the blade (), i.e. the centerline () of the blade cross-section and the perpendicular axis extending from the centerline. The cutting action and the force introduction of the conical cutter at the blade tip allow production of blade tips with a geometrically precisely defined edge without setting the respective blades into vibration.

Method for the manufacture of the blade tips of rotor wheels made in BLISK design

For shaping the leading edge () of blisk blades (), the shape, amount and disposition of the material to be removed in a subsequent grinding and polishing process is determined beforehand over the entire blade length. The blade leading edge is milled such that an elliptical profile () has a material allowance () which over the length of the leading edge exactly corresponds to an expected material removal during the grinding and polishing process, so that a blisk blade is produced whose leading edge features an aerodynamically advantageous shape.

Method for aerodynamically shaping the leading edge of blisk blades

With the fabrication of integrally bladed rotors or stators (blisks) for gas-turbine engines, where the space confined by the pressure and suction side as well as the annulus surface is shaped by cutting and machining from the solid material, starting at the periphery of a ring or disk, a stiffness-optimized pre-machining contour is cut out in a cutting process at a certain distance from the pressure and suction side along straight control surfaces at a cutting angle varying in correspondence with the blade twist and along a conical surface extending at a certain distance from the annulus surface as well as along transition surfaces between the conical and the control surfaces, and subsequently finish machined by finish milling to produce the final contour of the blade, annulus and transition surfaces. The method reduces tool wear and is cost-effective.

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Buedingen, Germany

Gregor Riedel