The CFM LEAP engine

Betting big on 3D printing

Engineers around the world are working hard to push the hottest technology of the decade over its tipping point. We take a look at what’s new with 3D printing.

It started off making smartphone holders, the little nozzle moving side to side, creating layers of ink that solidified and fairly swiftly you’d hold a fully made product in your hand. 3D printing - also known as additive manufacturing - has been in the news a lot in the past decade, with headlines screaming about researchers and engineers being able to print yet another object, from high heels to a chocolate bar.

But it’s not about to stop there - and some companies are betting big on 3D printing.

At Britain’s Sellafield nuclear fuel reprocessing, decommissioning and waste management site, the operators want to combine 3D scanning and printing to replace parts that are no longer made, many of which were created half a century ago. The alternative might be temporary closure of a plant, bringing reprocessing or clean-up work to a halt while a new component is custom-made. Tech industry giants such as Lockheed Martin and Honeywell are using 3D-printed components in their designs, and GE Aviation has recently invested $70m in a factory in Alabama to make 3D-printed fuel nozzles for its LEAP jet engine.

There’s a reason for this shift: what used to need the welding together of 20 parts can now be made by printing just one. And 3D printing can help to create parts that traditional manufacturing techniques could never achieve.

3D printing is not new; it’s just been painfully slow to fully take off. It has been around since the 1970s, and in the last several years it has finally made it into the industry at large, with companies using mostly plastic and metal to fabricate their parts, but some also starting to push the boundaries with other materials like ceramics.

One of the companies that does 3D printing on an industrial scale is the German firm EOS. It works with various types of plastic polymers and metals such as aluminium, stainless steel, nickel alloy and even titanium, printing flight-certified components for companies like Bell Helicopters. It has also manufactured titanium brackets for use in satellites made by Airbus Defence and Space. Not only are the brackets faster to produce, they also help reduce the weight of the satellite and withstand the high temperatures and external forces in space.

Another industry leader is defence company BAE Systems. Last year, it 3D-printed metal components of its RAF Tornado fighter jets and used them in test flights. The parts include guards for power take-off shafts and protective covers for cockpit radios. “The main advantage for us is the ability to produce parts quicker and cheaper,” says Matt Stevens of BAE Systems Military Air and Information. “There is also the benefit of being able to create one-off parts - spares - for aircraft without incurring costs and lead times.”

The company’s 3D-printed camera brackets were made from stainless steel using the selective laser melting process. “There is also a wealth of other parts produced using 3D printing, which are used in ground support for the flying fleet, and well established additive manufacturing facilities in place at a number of RAF bases,” says Stevens, adding that other metal production parts using this process are in the final stages of qualification.

But you don’t have to be an RAF pilot to fly in an aircraft with 3D-printed components. General Electric (GE) Aviation is using 3D-printed fuel nozzles in the newest generation of CFM LEAP turbofan engines designed for single-aisle aircraft. According to Todd Alhart, a spokesman for GE Global Research, the FAA has recently certified the CFM LEAP-1A engine, which has 19 fuel nozzles that have been 3D-printed. GE has received several thousand orders for the engine, which enters service in 2016.

Higher durability is one of the advantages of 3D-printed components, explains Alhart. “The 3D-printed fuel nozzle, for example, has five times higher durability compared to conventional manufacturing methods,” he says, adding that the 3D-printed parts are also lighter. For example, the number of components for the fuel nozzle has been reduced from 18 to a single printed part, which makes it 25 per cent lighter than its predecessor.

Buoyed by the success of the functional 3D component in a production system, GE is working to use it across other business interests as well. “In addition to GE Aviation, we have developed 3D-printed combustion for gas turbines in our Power business,” says Alhart. The company also has parts in development for medical imaging systems in its Healthcare branch, and for equipment in the Oil & Gas business. “By 2025, we expect additive manufacturing methods will be used in the design and manufacture of more than 20 per cent of GE’s new product concepts,” says Alhart.

3D-printing graphene

Graphene is often pitched as the super-strong wonder material for the 21st century. However, the process to create it in large quantities is expensive and may produce large amounts of toxic by-products. Researchers have been trying to fabricate graphene using 3D printers for some time now and their efforts are finally paying off. Graphene 3D Lab, a company based in Calverton, NY, has been exploring the creation of various 3D-printable filaments using graphene, and has recently filed a patent pertaining to the preparation and separation of atomic layers of the material.

“Right now we still manufacture materials in smaller quantities, so the price can be high,” explains Elena Polyakova, the company’s co-chief executive. “This patent will allow us to print graphene in high volumes at a much more affordable price. The new process is energy-efficient, not chemically invasive, and will significantly lower the cost of preparing and separating graphene nanoplatelets.”

Talking about the advantages of 3D-printed graphene for mainstream manufacturing, Polyakova says that the material is electrically conductive and can also be used to enhance mechanical strength and thermal conductivity. “Over the next 12 months, we intend to manufacture and put in place a scaled-up operation,” she adds. “We expect our unique combination of high-quality, low-cost graphene to significantly impact the commercial marketplace, and allow an ever-widening variety of manufacturers to consider incorporating the extraordinary qualities of graphene in wide range of materials from batteries to consumer electronics to plastics.”

Beyond plastic and metal

The palette of materials that a 3D printer can use as ink has been steadily growing. Besides plastic polymers, it now includes nylon, wax, sand and more. While most printers can print materials with only one type of ink, some high-end ones can squirt up to three at once. Recently researchers from the Massachusetts Institute of Technology (MIT) Computer Science and Artificial Intelligence Lab (CSAIL) even demonstrated a 3D printer that can print 10 different materials at once.

Dubbed MultiFab, it can produce items composed of different materials at the same time, instead of printing the different parts separately for later assembly. The CSAIL team says the printer can scan objects placed on its building platform and then print around them, opening up interesting applications such as the ability to directly embed circuits and sensors into printed objects.

While the MultiFab printer still sits inside the MIT labs, Jennifer Lewis, a materials scientist at Harvard University, is all set to roll out the Voxel8. This device uses a revolutionary conductive ink to print electronic circuits by drawing them in objects as they are being printed. This isn’t the first printer to use conductive inks, but unlike the current crop of carbon-particle-based solutions that make for poor conductors, Lewis’s ink is touted to be several thousand times more conductive.

Using it, you’ll be able to wire together chips and other electronic components within your 3D-printed objects, she says. The ink dries quickly and then the printed circuits are ready for use and can be embedded into objects. Lewis is already accepting pre-orders for the Voxel8, which currently works with two materials: PLA plastic and silver conductive ink. “Next, we plan to introduce a broader range of functional and matrix materials as well as a more advanced printing platform,” she says.

Thinking of the environment

Despite all the advantages, 3D printing isn’t always very environmentally friendly. Most of the inks used in these printers are created through processes that have a significant environmental footprint. That’s exactly what researchers at the Chalmers University of Technology in Sweden have been trying to address, using as ink cellulose extracted from wood pulp. It’s renewable and biodegradable, and the researchers say it can be used repeatedly, keeping the levels of carbon dioxide in the atmosphere in check.

Cellulose wasn’t previously considered a viable source of ink because of the way 3D printers work - using a heated liquid that solidifies when it cools.Cellulose doesn’t melt when heated, so the Chalmers team mixed it in a hydrogel that is between 95 and 99 percent water. This created the challenge to dry the printed gel-like objects without them losing their shape. “We have developed a process in which we freeze the objects and remove the water by different means to control the shape of the dry objects,” explains team leader Paul Gatenholm. “It is also possible to let the structure collapse in one direction, creating thin films.”

To increase the application of their ink, the researchers have mixed carbon nanotubes with the cellulose gel so that the ink can conduct electricity. By using the cellulose ink along with the ones infused with nanotubes, 3D printers can create objects with integrated circuits, much like the Voxel8. The next challenge for Gatenholm and his team is to use “all wood biopolymers, besides cellulose.”

3D printers could also usher in a revolution on the dining table, potentially opening new ways to feed the planet’s growing population. A few years back, engineers at the Netherlands Organisation for Applied Scientific Research (TNO) led by Kjeld van Bommel created a 3D food printer as part of an EU-funded project. Now they are working to widen the possibilities of 3D food printing by looking at not only at shaping but also at the creation of texture.

And in future, van Bommel adds, it may even be possible to use 3D printers to convert alternative readily available sources of nutrition, such as algae, into palatable dishes - but that could still be a long way off.

Full steam ahead

The technology is evolving rapidly. In 2013, design firm KOR EcoLogic, direct digital manufacturer RedEye On Demand and 3D-printing manufacturer Stratsys built the first road-ready, fuel-efficient 3D-printed car, Urbee 2, in 2500 hours. A year later, Local Motors 3D-printed the seat frames, cockpit, hood, tail and four fenders of the Strati electric car - in just 44 hours.

The biggest advantage of 3D printing is the ability to produce parts faster and more cheaply, says Stevens of BAE Systems. GE’s Alhart agrees: “These technologies are helping us to move faster up the development and commercialisation timelines. GE Aviation, for example, will introduce more new engine platforms in the next few years than they have in the past few decades.”

To propel the growth and adoption of 3D-printed components, both companies are also supporting research and development of the technology itself. BAE Systems is involved in several research projects with academia and other industrial firms, such as through the government-backed Innovate UK programme. Stevens says that the company is working closely with academic bodies to research and develop 3D printing in the aerospace sector, “such as exploring the use of this technology for large, structural metal components.”

But 3D printing has yet to enter the realm of mass production. “Currently, 3D printing is best suited for relatively low volume, moderate variety manufacture,” says Stevens, adding that in the short term it’s probably more of an enhancement to the production process. He doesn’t see it totally replacing traditional manufacturing even in the longer term, given BAE’s need “to optimise the very many parts of the aircraft for capability and for cost.”

However, GE’s Alhart has a different opinion. He claims that thanks to its CFM LEAP engine orders alone and some 200,000 fuel nozzles to print, GE is today the world’s largest user of additive technologies for metal parts. To print these parts, the company has constructed the first high volume additive production facility for metals in Auburn, Alabama.

We are at the cusp of what’s been referred to as the new industrial revolution. However, the real revolution that 3D printing ushers in might actually rewrite the definition of industry itself. Releasing production from the confines of a factory, 3D printing individualises industries that until now have been dominated by mass production. It allows for every single product to be made to measure as producers learn how to make things with mixed materials on an ever-increasing scale.

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