Rolls-Royce will flight-test later this year a Trent XWB-97 engine fitted with what it claims is the largest component ever built using additive layer manufacturing (ALM).

The titanium structure is a 1.5m-diameter and 0.5m-thick front bearing housing containing 48 aerofoils, manufactured using the ALM technique, also known as 3D printing.

The UK propulsion giant has already ground-tested several XWB-97s – the sole engine for the in-development Airbus A350-1000 – containing the tractor-tyre-sized part, but no engine including such a large ALM component has ever powered an aircraft in flight, says Rolls-Royce.

Although production XWB-97s will not contain the ALM component – at least not initially – the Derby-based company says the project is a key step towards proving the industrial viability of the process, which it says could trim 30% from "like-for-like manufacturing lead time".

Rolls-Royce will not commit to a timescale for industrial manufacturing of ALM components of this scale. "We don't want to put a date on it," says Alan Newby, chief engineer for future programmes and technology. "We have a lot of work to do on scaleability before making a commitment to production."

However, the benefits could be felt earlier in terms of the speed with which Rolls-Royce could develop prototypes using ALM technology, avoiding the need to commission tools to build a new component conventionally.

"It is ideal for prototyping. Shortening the manufacturing time by almost a third gives us more time to design, which is always a benefit," says Newby. "We are also able to produce designs that we wouldn't otherwise be able to do."

Rolls-Royce is not new to ALM – a technique by which metal powder is melted by electron beam and built ultra-thin layer by layer into complex shapes – having used it to repair components for at least five years. "We are using this knowledge now to build up to bigger components," says Newby.

The engine maker has been working on ALM technology with specialists from the UK's University of Sheffield and the Manufacturing Technology Centre, near Coventry, as well as Swedish-based Arcam, which makes additive manufacturing machines.

Rival GE is also investing heavily in the technology, and pioneered the manufacture of ALM components after buying Cincinnati-based Morris Technologies in 2012.

The second paragraph has updated to correct a reference to a "nickel" structure

Source: Flight International