MRO: 3D Printing for heat exchangers and metal brackets. P&W has made more than 2,000 prototype metal parts in an effort to speed up engine development. But Boeing has been the most prolific. It has researched and developed its additive manufacturing – also known as direct digital manufacturing – for nearly two decades and already makes some 300 small parts, primarily in ducts for cooling electronic equipment, which again illustrates the flexibility of 3D printing to form complex shapes and geometries.
Future challenges Despite all the expectations, it’s still early days; 3D printing remains more of a promise than a reality. There are still numerous issues, such as the use of certain materials, certification, repeatability, printing speed and scalability. For the moment, the costs surpass conventional manufacturing, but given the pace of technological advances, it won’t be long before faster and cheaper technology leads to a widespread adoption. “Because 3D printing is a new technology, there are still challenges,” says Cloran. “Because of the machine’s limitations, manufacturers are restricted to the size of parts that can be created in one build. Additive manufacturing can be ideal for making complex parts that would be difficult or impossible to make any other way. However, in general it’s still more efficient to make simpler parts through traditional methods. Also, 3D manufacturers are limited by the materials available, as qualifying materials for the process can be both time-consuming and expensive.” “Three-dimensional printing is a disruptive technology that requires a new way of thinking,” says Cloran. “We need to educate engineers and designers about how to think in 3D and not restrict themselves to the limitations of other manufacturing methods.” “The biggest challenge will be scaling up and the second will be understanding the new kind of design,” Sander concurs. “The world is trained on milling and moulding. No one knows how to use this and we understand the design principles to use the technology most effectively. Suppliers have to change their shops, ramp up their materials production. It really is a revolution.” “You also have to stay current with what’s happening in additive manufacturing,” said Boeing’s Hayes. “You invest in materials and certification and you can’t ignore the improvements taking place but that is difficult.” Still, there’s great potential. Boeing’s Sanders gives a glimpse of what might be possible. “We are already
scanning the entire aircraft, which could be printed in the next decades,” he says. “But, I think, this is really a dream. I don’t think we will print an entire aircraft. But we will print more using fewer resources and investment.”
What lies ahead? As the industry is only on the edge of 3D printing, manufacturers uniformly agree that 4D isn’t even on their radar yet. “Four-dimensional printing develops materials that alter their properties and behaviours based on external stimuli such as changes in temperature,” Jithendranath Rabindranath, a research analyst at Frost & Sullivan Technical Insights, explains. “It facilitates the self-assembly of materials required to manufacture parts and products, thereby speeding up the process and reducing the need for labour. In the near future, 4D printing will revolutionise the business landscape by printing objects ranging from human organs to parts used in the aerospace and automotive sectors,” he adds. The company expects the aerospace, defence, automotive and healthcare industries to be the first to adopt 4D printing technology after its commercialisation, but manufacturers disagree. NASA, which recently deployed a 3D printer to the International Space Station to study how it works in space, may be some way off using 4D manufacturing techniques. “We are doing nothing with 4D,” says Airbus’ Sander. “We know people are thinking about it. But there is no clear definition of what it means.” Boeing agrees. “We’ve seen it at universities, but it’s too low to catch our interest,” says Cloran. “It’s way too early to consider at this point. The things we design need to be stiff; when you start talking about morphing geometry and load paths start changing, that’s a long way out.” “Four-dimensional [manufacturing] is a new technology that is in its concept stage and does not yet apply to commercial aviation,” Cloran adds. “The promise is interesting and encouraging, but there are no viable applications in aviation that we are aware of or exploring.” While 4D printing is still some way off, it’s both surprising and encouraging how much has already been accomplished with 3D printing. It really is only limited by imagination. Boeing’s Dietrich says he would describe the company as having bridled enthusiasm for it. “We are enthusiastic but we are approaching it cautiously as well,” he says. Yet, it can also be said that he who dares wins.
afm • Issue 93 – November–December • www.afm.aero
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