New process chains could halve Blisk production costs, Fraunhofer IPT finds

In analysing Blisk manufacturing, researchers at the Fraunhofer Institute for Production Technology IPT in Aachen have found that production costs could be halved by conducting innovative process chains.

This, the researchers feel, is strong motivation to increase effort for the development of advanced manufacturing processes for serial production of the aircraft engine ‘blade integrated disk’, or Blisk.

A large proportion of the production costs are fixed machine costs: depending on the process chain, these can vary between 20 and 70 per cent.

The team at Fraunhofer IPT compared different process chains from an economic and technological point of view, along with their colleagues from the tool machine laboratory WZL at RWTH Aachen and EMAG ECM.

‘We looked at a total of seven different process chains based on a Blisk made of nickel,’ explained Daniel Heinen, manager of the business unit Turbomachinery at IPT.

To achieve an objective comparison, the research team looked at a few promising alternatives alongside conventional milling from a solid block: electrochemical machining ECM, water jet machining, and wire-based laser metal deposition, a manufacturing process for the layer-wise build-up of the blades. In each of these processes, however, the surfaces have to be reworked, for example by automated polishing or by precise electrochemical machining PECM.

Specially developed software made it possible to calculate the resource requirements of the different manufacturing process chains and technologies in a comparable way.

The researchers recorded all the information for each process chain: economic and environmental constraints, such as the cost of the machinery, the production times, the expense of CAD/CAM programming or the number of components to be manufactured, allowing not only the production cost to be identified, but also the primary energy demand and the CO2 balance.

The assessment methodology is independent of the component shape and can be easily adapted to different geometries and manufacturing processes and changes in volumes. By studying the individual processes technologically, the researchers can also identify resource requirements for the manufacture of alternative component geometries more specifically, deduce dependencies of various production processes and thus help companies make a decision when it comes to choosing the right process.

The researchers will be presenting their results at the Berlin Air Show ILA from 1 to 4 of June (Hall 4, Stand 202).

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