East Hartford, Conn. – High-value jet engine components such as BLISKs (blade integrated disks) are currently manufactured by material removal of the forged raw material or linear friction welding (LFW) of pre-milled BLISK blades onto the pre-turned disk. Processes used for the material removal are 5-axis milling and electro chemical machining (ECM), processes that cause waste and material losses and are time and cost intensive. Therefore, the buy-to-fly ratio is approximately 5:1.
A project at Fraunhofer ILT, Aachen, Germany, called "Additive BLISK Manufacture" is qualifying and certifying laser metal deposition (LMD) as an alternative key enabler for the green manufacture of new and future generation parts such as BLISKs made from nickel and titanium base alloys.
At the April 13-14 Symposium for Advanced Laser Application (Hartford, Conn. – SALA), Ingomar Kelbassa (Fraunhofer ILT) will discuss the project from the first feasibility studies via the subsequent process development to a first additive BLISK-mock-up manufacture for a HPC BLISK made from In 718. The results are outstanding: defects can be avoided completely. The achievable static and dynamic mechanical properties are comparable to a forged component and can be guaranteed by applying appropriate temperature-time cycles during LMD and by an appropriate post weld heat treatment if needed.
This deposition rate guarantees additive manufacture of a single blade in less than 2 minutes. At a maximum 80 blades per BLISK, this leads to a calculated additive manufacturing time of approximately 160 minutes. Compared to manufacture by 5-axis milling, material savings of up to 60% (buy-to-fly ratio = 2:1 instead of 5:1) and a significant reduction of the entire BLISK manufacturing time by approximately 30% have been achieved so far using additive manufacture.
Therefore, laser additive manufacturing (LAM) is predestined to contribute to our grand societal challenges – resource saving, energy, mobility, and health – significantly.
This LAM success story and many other cost effective laser processes will be presented at this year's SALA.