Maarten Logtenberg didn’t always make large-format 3D printers and hybrid additive CNC machine tools. In fact, his first business venture delivered a desktop fused deposition modeling (FDM) machine with a build volume barely big enough for a lunchbox.
How times change. “Our largest machine so far has 40 meters of X-axis travel and was first used to print a one-piece ferry, complete with an electric motor inside,” says Logtenberg, the co-founder and chief technical officer of CEAD Group BV in Delft, western Netherlands, and recipient of the 2023 Composite Manufacturing Emerging Innovator Award.
His LinkedIn tagline? “We build and deliver extra extraordinarily large 3D printers.”
Accomplishing this is more than a matter of scaling up. For starters, CEAD Group’s short-fiber reinforced thermoplastic pellet 3D printers, not to mention their latest advanced tape layer additive manufacturing (ATLAM) technology, are much different from the hobby-grade FDM machine Logtenberg designed while attending the Delft University of Technology. Rather than polymer filament, CEAD’s custom robot extruders use pelletized feedstock similar to that found in plastic injection-molding machines. ATLAM goes one step further, combining continuous fiber-reinforced composite tape laying with large-format additive manufacturing (AM).
Both technologies present all manner of heating and pressure control challenges that don’t exist with their smaller FDM counterparts. Further, the parts produced with CEAD’s machines follow a different set of design for additive manufacturing (DfAM) guidelines, especially considering that many of them are multiplanar, able to print angled, ramp-like surfaces in three axes simultaneously.
Complicating matters even more are the composite materials they use. Some are basic commodity-level polymers like PLA and polypropylene (PP), while others, such as PEEK, PA6 (Nylon), and polyethersulfone (PESU), provide engineering-grade performance. But all contain between 15% and 40% by weight of carbon, glass or cellulose-fiber additives, endowing even ordinary polyethylene terephthalate (PETG)—the stuff of plastic jugs and food containers—with greater strength, stiffness and dimensional stability, properties that are critical for large-scale 3D-printed structures.
“We can process quite a wide range of materials, which is great, but cost is another important consideration when printing something the size of a car or the bridge it may one day drive across,” Logtenberg says. “Depending on the polymer, you could be looking at a couple of euros per kilogram to up to 150 euros or more (about $73 per pound). High-cost material is no big deal for small printed or injection-molded parts, but if you plan to make a large boat from one of those more expensive materials, you probably don’t have a viable business case.”
Still, large-format printers, when coupled with high-performance composite materials, are already making significant inroads into many of these markets. For example, CEAD Group is not the first 3D-printer manufacturer to successfully build layup fixtures and molds for the aerospace and other markets, as it did with a large autoclave tool for an automotive application.
“When compared to aluminum or tool steel, composites are much less expensive, especially because you only have to use as much as you need—we can print hollow or honeycombed shapes instead of a solid block, so there’s less material waste and the manufacturing time is much shorter to boot.”
These polymers are not only quite abrasive but are extruded from the nozzle at unprecedented rates, although Logtenberg is quick to point out that the head design accommodates each of these demands quite easily. Some are also quite large: If printing were a boxing match, one of CEAD’s extrusion heads—the E50—would easily qualify in the heavyweight class.
“We have several models, but our largest deposits material at rates up to 85 kilograms (187 lbs) per hour and weighs roughly twice that. You need a fairly large arm to handle that much mass, although given the capabilities of today’s robots, that hasn’t proven to be a problem.”
The last statement illustrates another important differentiator between CEAD Group and its competitors. Most large-format 3D printers utilize a gantry system for motion control like those found in CNC machining centers. And while the company also leverages this type of construction on certain printers, the lion’s share employ a robotic arm to put the extrusion head through its paces. This accounts for the multiplanar capability noted earlier.
But printing in three axes at once presents its own share of difficulties, not the least of which is the possibility of crashing the print head into a previously printed, non-horizontal surface. Because of this, programming the arm and its attached print head proved to be an early roadblock. “Initially, we used a standard 3D-printing package to control the robot; but it had no simulation tools, so it was always a bit of a guessing game as to where the head would end up after each pass.”
Logtenberg and his team worked on developing software in-house but quickly decided to focus their efforts on what they do best—machine tools and 3D printer development. CEAD partnered with Siemens, whose well-known NX platform turned out to be just the trick for complex programming problems, and CEAD has continued to build on this relationship. Yet recognizing the need for customer choice, Logtenberg began working closely with other partners such ADAXIS and AI Build—software-as-a-service providers known for their industrial AM automated toolpath generation capabilities.
Says Logtenberg, “It turned out to be a great move for us, so we basically opened up our hardware and began collaborating with several parties to make sure our customers have options.”
The early Siemens partnership was fortuitous because CEAD soon began working with them on a way to replace the standard robot control they had been using. “It’s the same Sinumerik 840D control they use in high-precision, five-axis CNC machinery, so we can control the robot directly using standard G-code.”
It has also opened the door to additional capabilities. For example, CEAD’s robotic 3D printer, the Flexbot, is equipped with a tool changer and milling spindles, so can machine parts and features after the part has been printed. In a nutshell, it makes CEAD Group a hybrid additive machine builder as well as a designer and manufacturer of large-format 3D printers.
“We consider ourselves a full-service solution provider,” Logtenberg says. “As such, we like to partner closely with our customers because, in the end, there’s much more to this than the printer. There’s also software, materials, integration with other machine tools, automation, process development, machining and post-processing—there’s a great deal to delivering high-quality, predictable parts, especially when you’re looking at large-scale printing.”
Ask Logtenberg’s customers. One of them—USA-based Haddy—will soon sport eight of CEAD’s hybrid-additive machines equipped with onboard 3D scanning at its new factory in Florida, having collaborated extensively with CEAD on the floor layout and process development. As its name suggests, the company produces tailor-made furniture. But because it uses parametric design and 3D printing, it’s far more efficient than traditional cut, glue and screw furniture making.
“They’re certainly pushing the limits in terms of manufacturing technology and environmental awareness, and have a long-term vision to build multiple micro-factories so they can do local manufacturing. It’s a very cool business model.”
In another use case, a manufacturer of decorative architectural components found its legacy bending, welding and powder-coating processes were growing too labor intensive to be competitive. The company turned to CEAD and purchased a large-format 3D printer, but like many AM newcomers, soon discovered that some level of product redesign would be necessary.
What they didn’t anticipate was the time it would require. This common 3D-printing prerequisite consumed several hours or more per component, and with 10,000 designs in its database, the engineering department was looking at many years’ worth of DfAM effort. Logtenberg quickly came up with a solution, leveraging his team’s software engineering experience to develop a custom tool that would take the initial designs and make them printable within a minute.
“It was a game-changer for them,” he says. “It wasn’t long before they bought a second machine, and now both printers are running around the clock, every day of the week. I like to tell this story because it illustrates that, in order to replace or augment conventional manufacturing methods and make this technology a success, you need to look at the entire scope, from design to finished product. That’s where we really try to make a difference.”
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