Hold tight: General Industry Coverage

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END USER: MTU Aero Engines GmbH, +49 89 1489-0, www.mtu.de. CHALLENGE: Minimize cutting tool vibration and runout when circular stagger milling titanium blisks. SOLUTION: A hydraulic toolholding system that dampens vibration and minimizes runout. SOLUTION PROVIDER: Rego-Fix Tool Corp., (317) 870-5959, www.rego-fix.com

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Courtesy of Rego-Fix

The blisks MTU Aero Engines manufactures have stringent accuracy specifications, requiring the use of the Rego-Fix powRgrip toolholder system (inset), which includes a holder, collet and miniature press that generates 6 tons of force.

The growing and competitive blisk (BLade Integrated diSK) market requires continuous improvement of the manufacturing process and the development of more-efficient machining strategies. Blisks are found in heavy-duty compressor rotors in military and civil turbine aircraft engines and commercial compressors.

MTU Aero Engines GmbH, Munich, Germany, machines titanium alloy blisks and determined that conventional milling takes too long. To improve the process, the company developed toolpath programming to perform 5-axis circular stagger milling when roughing. With CSM, the cutting tool moves on a circular track through the canal between the part’s blades. Because of the changing width between blades, the diameter of the circular track is constantly adjusted, enabling surface finishes typically achieved when finishing to be imparted when roughing. “There are programs that can do circular stagger milling, but on a 3-axis basis and not on a 5-axis basis. You need the latter for air foils,” said Götz Lebküchner, materials and processing engineer at MTU.