Today’s riddle: When is the phrase ‘cutting edge technology’ an oxymoron? Give up? Ok, we’ve got an answer: When it’s applied to additive manufacturing. Can we see a show of hands for those who got that right first time… Excellent – we have the best readers here at Cleanroom News.
Additive manufacturing – also known as 3D-printing – is a decidedly 21st century technology that is shaking up industries from aviation to biomedical, from military applications to motor vehicle innovation.
And it’s not hyperbole to state that it is revolutionizing the ways in which industrial manufacturing approaches design and development. From offering designers a new degree of freedom in how they conceive components to presenting financiers with tangible savings, additive manufacturing is replacing the subtractive paradigm in myriad industry silos. Let’s take a look at just one of them today, aviation…
Throughout the history of aircraft innovation, the machines that carry us aloft – from those early by-planes of the Wright brothers to Boeing’s all-new 777X – have had one thing in common. Wings, yes, but that’s not the answer. The common factor is actually their creation via subtractive manufacturing – the cutting, milling, and drilling – of conventional processes, and this convention is inherently limiting. From hand-fashioned rivets to the use of lightweight carbon-fiber to the contemporary printing in liquid metal, manufacturing methods have striven to create increasingly high-performance parts with absolute safety in mind.
In March 2016, General Electric (that iconic American company founded in 1892 in Schenectady, NY) began testing the GE9X jet engine in its Peebles, Ohio, facility.(1) Envisioned as the largest jet engine ever to be built, the GE9X is a combination of superlative efficiency and power with an increase in heat resistance that would be the envy of its competitors. Measuring 11 feet in diameter, the engine boasts an equivalent thrust of 100,00 pounds – equating to one-third that of the space shuttle.
And perhaps this is all the more remarkable because much of the engine is manufactured in a cleanroom via 3-D print technology.
From the sculpted fan blades to the use of ceramic-composite lining for the engine swirlers (imagine blenders that mix air and fuel) that – withstanding temperatures up to 2,400 degrees Fahrenheit – outpace traditional metal linings, the use of a cleanroom for manufacture is essential. And even the airfoils are created in additive mode. Given the thrust load of the GE9X engine, the traditional material – nickel – is too weak, so airfoils are fashioned from a titanium-aluminide powder for extra strength and heat resistance.(2) Components such as these are often printed using Direct Metal Laser Melting, the fusion of ultra-thin layers of powdered metal via a 200 watt laser. And although it may seem that, when viewed in isolation, each change is quite small, taken in aggregate the upgrades form a very different picture of the manufacture of the craft.
And additive manufacturing produces not only new components but also new material alloys, making parts lighter, stronger, and potentially cheaper than before – viz GE’s celebrated fuel nozzle. Typically, fuel nozzles in jet engines are subtractively manufactured from around 20 separate parts and suffer a common problem. Over time, in a process termed ‘fuel coking,’ carbon deposits build up as jet fuel is sprayed into the combustor, leading to a degradation of an engine’s durability and ultimately compromising safety. Using AM technology in the TAPS III combustor, GE engineers have redesigned the nozzles for the jet engine to allow for pathways to cooling, generating what the industry describes as ‘lean-burn’ – with a 27:1 air to fuel compression ratio – and increasing the part’s durability by a factor of almost five. One nozzle printed from cobalt-chrome powder is now safer, more durable, and easier to handle – and yet is strong enough to tolerate temperatures as hot as 3000 degrees. And when we add in the fact that additive technology allows for a quieter running machine that it is up to 25% lighter in weight, the fuel cost savings start to add up too.
According to an article in Quartz, the ‘digitally native news outlet’, GE has more than 700 orders for the GE9X which will go into production in 2020. This represents a cool $29 billion which is presumably why, between 2013 and 2018, GE was slated to invest more than $3.5 billion in AM technology, for the machines that manufacture the 100,000-plus additive parts it will have in inventory when GE9X production begins.(3) And this conversion from subtractive factory-based fabrication to additive manufacturing in a cleanroom environment is not the sole remit of one corporation –
it’s a common goal in many sectors of the industry. Let’s also look at GE’s partner in aviation technology, Boeing…
In Everett, Washington, Boeing Co. has unveiled a brand new production area. Known as the Composite Wing Center, the plant recently opened at a cost of more the $1billion with one simple mandate: to construct the longest wings of any commercial jetliner for the much acclaimed Boeing 777X. Heralded as a massive step forward in design and pushing the boundaries of production technology, the plane will boast not only the biggest composite material wings – at 110 feet in length – but will also be made of lighter and radically stronger materials than ever before. So before wading into the specifics, let’s review a snapshot of current metrics. If you’ve ever flown coast-to-coast here in the U.S. you may have enjoyed a few hours confined to the relative comforts of a Boeing 767. This wide-bodied workhorse of the domestic long-haul skies has a typical combined wingspan of 156 feet, dual turbofan engines, and seating capacity for between 181 and 375 passengers. With a design range of up to 6,385 nautical miles, the 767 also puts non-stop service from the U.S. within range of medium- to long-haul intercontinental flights.
But all of this aeronautical glory pales in significance when compared with the capacity of the soon-to-be 777X. As Eric Lindblat, head of Boeing’s development program, noted ‘“This carbon fiber wing – there’s nothing like it in the world.”’(4)
Hyperbole aside, just how different is the production of this craft, what is the cleanroom role, and what does it all mean for passengers?
According to Boeing’s promotion materials, instead of titanium the 777X uses hyper-efficient carbon composites for its fan blades, whose aerodynamic profile and contoured, foldable wingtips cut aerial drag. Inside the craft, ‘top-yielding’ passengers enjoy the comfort of cathedral ceilings in an extra wide cabin into which one additional seat per row can be installed in the event of unforeseen passenger needs. Purpose built for long haul flights – for example, from Los Angeles to Dubai in the United Arab Emirates – the 777X not only exceeds the maximum travel distance of its closest competitor by a whopping 1500 nautical miles but can also do it more efficiently, with a saving of 12% per seat on fuel with an accompanying reduction of 12% in CO2 emissions. In terms of Nitrogen oxides – a family of gases including Nitrous oxide, a greenhouse gas that contributes to climate change – the emissions fall 29% below the most stringent CAEP/8 limits for engines with a thrust greater than 26.7kN.(5) And all of these improvements have also been accomplished while maintaining a reduction in excess weight (of some parts) of a full 50%.
And again, the role of the cleanroom in manufacturing will be critical to the final rollout of the craft.
Measuring in at a cool 1.3million square feet, Boeing’s Composite Wing Center facility in Washington devotes approximately half of its floor space to a contamination-controlled environment.(6) The cleanroom is integral to manufacturing parts of the wing – from stringers to spars and skins – and the absolute sterility is critical. Says Lindblad: ‘“You could get someone walking through the factory like you or I. We could have a piece of dust in our pocket. It could float out of our pocket and end up between two pieces of material, and no one would ever know it had happened.”’(7) And since such contamination could be costly in terms of production delays, materials wasted, or safety compromised, that absolutely cannot be allowed to happen.
As we’ve discussed in other 3D-printing articles, the use of additive manufacturing both within a cleanroom environment and in everyday life is limited only by our imagination and our reach. We’ve seen that the field is wide open for everything from peach packing (‘Tentacles of Innovation – Is the Future of Robotics Going Soft?’) to bio-medical advances (‘How the FDA is wrestling with bio-medical 3D-printing’). We’ve been surprised that the tech is not bounded even by our own gravity (‘Out of this World – When Cleanroom Technology Enters a Whole New Orbit’) and fantasized about purchasing our very own 3-D fast food printer (‘Pizza, Hot and Fresh – Direct from the…3D Printer?’. And now we wonder – with a certain degree of excitement – about the intersection of these uses: instead of sitting, yogi-like, with your knees pressed up to your ears in economy class for hours on end, imagine stretching out under cathedral ceilings aboard the 777X. In place of that formless, beige gruel of uncertain provenance, imagine a lunch of fresh, 3-D printed margherita pie as you speed across transatlantic skies. The future is indeed additive and it is here!
Do you have thoughts on additive technology? What is the next big application? We’d love to hear from you!