Additive manufacturing (AM) is being used to fabricate parts for applications as varied as aircraft and auto production, dental restoration, medical implants and more. By redefining standards and changing certification and classification systems for various industries, AM is changing the way manufacturers create, customize, repair and produce parts.
Applications for AM include parts that are small, large and in-between. For example, at one trade show a few years ago, Cincinnati Inc. printed a 1,000 lb car body in just 44 hours. Harrison, Ohio-based Cincinnati markets its own BAAM (big area additive manufacturing) and SAAM (small area additive manufacturing) 3D printing machines, according to Rick Neff, AM product and sales manager.
BAAM is an industrial-sized additive machine using the design and technology from Cincinnati’s laser platform—including the machine frame, motion system, and control—and is adapted with an extruder and feeding system. SAAM is optimized for carbon-fiber composite 3D printing and enables continuous, unattended 3D printing via Cincinnati’s patented automated ejection system.
The fast-growing interest in large-part AM is being driven by the exponentially faster speeds in production scale projects, according to Don Edens, emerging market manager for Techmer ES, a wholly owned subsidiary of Techmer PM LLC, Clinton, Tenn., a manufacturer of high-performance custom compounds used in the plastics industry.
Edens noted that conventional manufacturers of large carbon fiber reinforced polymer (CFRP) parts, for example, produce tools or molds for a specific part, buy material and shape it to the desired geometry, then do a carbon fiber layup. Letting it cure and doing more subtractive work, along with the lead time required, means the process can take well over a year. Using AM, a shop can design and print the part, design and print the tool, and produce a part off the tool in the space of a week.
Another significant difference is not being locked into one design for months and months. AM technology means tools now can simply be reprinted if changes are needed or design specs change. Edens pointed out: “It’s a game changer for speed and design flexibility.”
Such advancements, of course, do not come without challenges. One obstacle is improving Z strength, Edens said. “If you go in the direction of 3D-printed layers, you have very low coefficient of expansion and high strength of the fibers. But when you go vertical, the properties are different. There’s a lot of technology going on right now, both chemically and mechanically, to change that. Machinery is evolving. Several large printer manufacturers now have products on the market. There’s a lot of talk [that AM capabilities] could grow to be the size of the injection molding industry. That might be a stretch in five years, but AM is definitely the next frontier.”
In terms of design innovation, the cutting edge lies in part consolidation (making hollow objects) and topology optimization (strength only where needed). Working also with emerging technologies, David Leigh, senior vice president at Stratasys, explained that when hollow objects are produced by traditional manufacturing, a left side and a right side are made to be pieced together. (After this article was written, Leigh was named CEO of Vulcan Labs Inc., a spin-off of Stratasys based in Belton, Texas, with the goal of developing production-focused solutions based on powder bed fusion technology.)
“With 3D printing,” he said, “you can actually make things hollow as you build them. Where that’s used in energy applications is in conformal cooling, or cooling channels, where they can actually make these complex tube shapes that fluid flows through. In addition, we’ve helped with topology optimization, where you can actually lightweight the part. If you’re making something out of wood or steel or plastic, you typically cut away what you don’t want. But if you look at nature, on a tree the branches are only there to hold up the limbs. The limbs are only there to hold up the leaves. It’s not a big block. So, what you do with topology optimization is remove a lot of the weight. And you get these organic-looking shapes.”
Savings on time are coupled by savings on equipment costs thanks to 3D printing’s ease of pre-machining tool design. The oil and gas industry is already reaping enormous benefits from AM. Because worker safety is crucial, being able to test various elements of drill operations, for example, before machining parts to go underground means risks become fewer, improving on-the-job safety.
Leigh said: “They do a lot of high-pressure, high-heat vessel testing before they do any drilling. We’ve probably done more work in that down-hole drilling area to help test the oil rigs because they’re pretty expensive to operate. What we help test is the actual shape and form of drill bits. Sometimes we would make a prototype and sometimes we would make a pattern where they could take the part and convert it to metal through investment casting or some other type of casting. They also have these sensor arrays to understand temperatures and other conditions.
“The other one, I would call a lot of it guts,” he continued. “You crack the plastic housing of a machine and you see all these random parts. They could be metal. They may be bearings. So we would make the guts. They could go into assemblies, from plastic and metals. Finally, the ability to check fixtures is important. Once they’ve proven out in design, they’ve been tested and are ready to go into manufacturing; sometimes we would make [prototype] parts, even clear parts. [The customer will] actually machine these out of some Inconel-based alloy, or another superalloy, for the more rigorous or caustic environment they’re in. We would make a prototype with the channels if they have hydraulic fluids or cooling fluids, or channels where they have to run sensor arrays. We’d make prototypes out of clear plastic, so they could actually double-check and make sure their design was right before having it machined.”
Leigh noted that the largest oil-field part Stratasys made was part of a shaft that was a 6-8′ (1.8-2.4 m) section. “We would make it in pieces and assemble it,” he said. “We use thermosets and thermoplastics, generally nylon, ABS, sometimes Ultem. The other one is metals—Inconel, cobalt-chrome, titanium-aluminum, stainless. They like Inconel 3D-printed because it’s very hard to machine. If we can get them to near-net shape, it saves [customers] a lot of time and money.”
AM manufacturing has three areas of expansion. The first is adoption, with a lot of growth in low-end prototyping. It means architecture or engineering firms can purchase a 3D printer for their office for as little as $5,000. Elsewhere, production of machines that process metals is probably seeing the largest sustained percentage growth, about 70 percent a year.
But, if you want to know where the real radical growth is happening (imagine a graph shaped like a hockey stick), look at software development for niche technologies. Although lots of work is being done in this field, only a handful of companies are ahead of the curve with 3D printing applications. However, established giants like Siemens and Dassault Systèmes are now discovering its potential.
As always, when technology advances, some elements are left behind. Currently out of favor is the industrial-grade polymer plastics printer. But Leigh insisted the laser-based machines have an important role to play in the long term as sectors such as aerospace expand. As a result, the potential is ripe for any and all innovations.
Metal materials for AM have been somewhat limited, particularly in powder-bed fusion, the most widespread metal 3D printing technology on the market. Its global market will grow to around $12 billion in just 10 years, market researchers IDTechEx has predicted. This growth will not only be caused by greater adoption of the technology as prices drop and new technology emerges, but also by the materials portfolio itself expanding.
John Murray, president and CEO of Concept Laser LLC, Grapevine, Texas, said his company focuses on coming up with new materials, propelled by the 75 percent acquisition of the firm by GE in 2016. When one thinks of laser sintered parts, stainless steel and titanium come to mind. But a lot of “exotic work” is going on in new alloys as well as with Inconel, copper, and titanium-aluminide.
Also, “some smart people out there” are innovating with proprietary powders that will bring ever-greater precision, as well as saving even more time and money. “There are so many materials,” Murray pointed out. “One of the powers of GE is material development. So, I think we’re developing three or four new powders per quarter as a goal. It’s a little humorous. Once or twice a week I get a call from an engineer asking something like: Can you print ‘Godzillium’ on your system?”
AM technology can also bring a lot of fun to the workplace. Murray said: “We did a project on a P-51 Mustang from World War II. We took off an exhaust stack because those exhaust stacks go through many heat cycles. They tend to crack. [The stack is made of] four parts and they’ve got 34″ [863.6 mm] in weld seam. We scanned it, looked up the original drawings and printed that. I thought it wasa great application of looking forward at how we are going to do this in the future while also keeping iconic aircraft like the P-51 flying with the original design criteria, but with four parts reduced down to one. You could optimize that for performance with computational fluid dynamics.”
Being a pilot himself, Murray was asked if he was ready to have laser-sintered parts on his own plane. “The sooner the better,” he said. “There is a provision within the FAA rules that an owner of an aircraft can reverse engineer and manufacture components for his own airplane. So, I’ve started that. My plane was built in 2002 and there are some areas where we can improve airflow, so we’ve designed a duct. It’ll be lighter. It’ll be stronger and much more efficient than the original design. That’s not for flight-critical parts. We’re not there yet, but it’s an example of how you can improve an existing product.”
A crucial advantage of laser sintered production is being able to quickly and easily verify the design, with great benefits derived from early and regular prototyping. Murray said talented engineers are always needed.
“I heard an interesting story [about engineers who] came into additive. And they said, ‘Yeah, this is interesting. It’s printing. But what’s the big deal?’ Then, suddenly the lights went on when they realized they can take X number of parts and reduce them to one part. Take the advanced turboprop engine that GE’s building. They’re taking 855 parts down to 12. That’s just amazing. All the cast parts are gone. They’re going to be printed. You have the part-count reduction. You have improved fuel economy. You have all kinds of downstream advantages from a logistics standpoint, as far as spare parts and support go. It ripples through the product lifecycle.”
So, what to make of it? What kind of future does your business have with AM? The outstanding factor in all of this is that complex parts can now be produced without any tooling and without the design constraints of conventional manufacturing methods.
Components can be made today that would not have been possible even just a few years ago. Not only that, 3D printing has achieved a geometrical complexity that cannot be matched by any other production technique.
No longer consigned to just prototyping technology, AM has reached the standards required for high-end series components for the most demanding of industry applications. With ever-faster systems using stronger lasers and bigger build chambers, the technology will likely continue to grab an increasing market share of production processes.
Editor’s Note: The article is based on a roundtable discussion at the HOUSTEX 2017 conference.
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