Pratt & Whitney’s president of aftermarket, Matthew Bromberg, predicts that maintenance, repair and overhaul (MRO) shops in the future will “print” the parts they need with additive manufacturing technologies, speeding up repair tasks and reducing stored inventory.
“It will work. It will be efficient. It’s the way the industry will go,” said Bromberg, speaking at Aviation Week’s MRO America conference in Phoenix on April 9.
While additive manufacturing for metal parts will no doubt change the MRO landscape, it is not clear how quickly the nascent technology will take over, particularly for safety-critical parts where certification hurdles remain.
General Electric is a key contender in bringing the capability to market, highlighted by a fuel nozzle it is building for the new Leap turbofan engine that will power the Boeing 737 MAX and Airbus A320NEO later this decade. Mike Cloran, with GE Aviation, says the single-part additive fuel nozzle replaces a legacy fuel nozzle design requiring 20 separate pieces that had to be welded or assembled, and the new part weighs 25% less. The company expects to move into full production of Leap nozzles by 2015-16, with 50-100 additive machines producing 40,000 nozzles per year by 2020. With 19 nozzles per engine, the production rate will support the delivery of 175 engines per month (or 88 aircraft per month), assuming a 100% acceptance rate for the nozzles.
Additive manufacturing technology involves laying down one layer at time of a metal powder and joining the layers with a laser. Cloran notes that “100%” of all additive parts require some post-production work, often involving machining or polishing.
While the Leap project represents only one of the thousands of parts in a jet engine, Cloran points out that additive manufacturing for metal parts has only been in existence for 10 years, and applications for the technology are expected to increase exponentially, particularly beyond 2018 when the process is expected to be able to use multiple metals to create designer alloys. New predictive analysis tools that identify failure points with computer-aided design (CAD) models, and offers solutions in advance of production will also help. Certification of the new parts is currently a hurdle, says Cloran, but the issues are solvable.
For new-production aircraft, Cloran expects additive parts to first show up for interior applications, where weight savings are key for parts that are not considered safety-critical. For MRO shops, he says additive machines will be important for supporting end-of-life component replacement where parts obsolescence is an issue. “Additive will have an impact on inventories,” says Cloran. “You won’t have to keep an inventory of old parts.”