Cosine Additive Takes on Traditional Manufacturing with Big, Fast 3D Printing
Michael Molitch-Hou posted on June 30, 2016 |
ENGINEERING.com looks at polymer extrusion 3D printing with Cosine Additive, ORNL and Techmer ES.

Now that the media hype around 3D printing has fizzled out, innovation associated with the technology can continue—unhindered by exaggerated claims and marketing fluff. While the energy in the industry shifts away from consumer printers, the timing may prove to be perfect for a company like Houston-based Cosine Additive to advance 3D printing in the industrial space. 

After two years of development, the startup made its debut at RAPID 2015, lugging a 2,000-lb behemoth of a printer onto the showroom floor. At first glance, the AM1 might look like another RepRap derivative blown up in size, but, upon further inspection, it becomes obvious that Cosine Additive brings some unique features to the table to set its technology apart from other large-scale 3D printers on the market.

In fact, these features have caught the eye of some interesting partners in the 3D printing space that may speak to the quality of Cosine’s technology. With Essentium Materials, the Texas startup is aiding in the application of a thermal welding process that could improve the strength of parts printed with extrusion processes. 

The thermal welding printhead developed by Cosine Additive and Essentium Materials.
The thermal welding printhead developed by Cosine Additive and Essentium Materials.

Perhaps more exciting is the work Cosine is performing with the Department of Energy’s Oak Ridge National Laboratory (ORNL), which will see the AM1 platform evolve to produce parts at speeds unattainable with most extrusion 3D printers on the market.

3D Printing with Partners in Mind

In an interview with ENGINEERING.com, Andrew McCalip, cofounder and CTO of Cosine, and John O'Connell, vice president of sales and marketing, explained that the AM1 was created as a platform onto which others could innovate their own ideas.

“I saw a lot of polymer companies reinventing the wheel and building motion systems in-house,” McCalip explained. “I also saw a lot of universities building their own CNC robotics to even begin their research on filament extrusion. I thought that was very silly because everyone in the world doesn't have to be good at CNC motion systems and software and hardware and all of that. They should have an open platform on which to do their research. That’s exactly where we’ve fallen into. We want to be the platform and let the other scientists do what they do best.”

It was this open approach that helped to facilitate partnerships with Essentium Materials and ORNL. However, it is the mechanical engineering of the AM1 system that enables these partners to 3D print large-scale objects with industrial-grade materials. 

The AM1 3D printer from Cosine Additive. (Image courtesy of Cosine Additive.)
The AM1 3D printer from Cosine Additive. (Image courtesy of Cosine Additive.)

“We started off buying all of the best open-source, hobby-grade equipment on the market: extruders, hot ends, nozzles, heaters, etc.,” McCalip said. “They just didn’t meet our quality standards. Everything on the AM1 is now custom-engineered. There isn’t one part on our machine from the general 3D printing marketplace. It’s all custom CNC-manufactured in-house—all of our own design, even down to our extruder hobs.”

The Importance of Thermal Stability

These custom parts also include the enclosure system that is key to the production quality of the AM1. As McCalip pointed out, the case housing the printer is “more than just a box.” While other large-scale systems on the market are often based around open-air gantry architectures, the AM1 enclosure has been engineered to maintain the thermal stability necessary for 3D printing large parts that don’t warp. 

“We built the AM1 from day one to have the enclosure because the large format is really useless without it,” McCalip explained. “Even PLA parts tend to warp at that size. If you want any hope of printing flat parts, you have to thermally manage the environment.” 

To illustrate his point, McCalip described a recent ABS print that was 24 in long and 18 in wide and manufactured with the doors of the AM1 held open. Due to the lack of thermal control, McCalip said, the component warped to such an extent that the glass it was printed onto curved 6 in on either side of the print before shattering completely. 

“That’s how strong the thermal contraction of the plastic was. It was able to shatter a piece of ¼-in glass,” McCalip added. “The residual stresses inside the part that occur when you print in open air are so strong. We took the same part and printed it in a 70 °C chamber. It was dead flat on the bottom with no warp whatsoever.” 

The high-temperature upgrade to the AM1 is, in particular, built with this thermal stability in mind. It features dual-pane, argon-filled glass on all of the windows, rather than the single-pane glass of the basic version. The 1-in thick panels are built with high-grade polyiso insulation. The interior surface of the machine is also completely sealed. Additionally, the high-temperature model includes upgraded wiring and motors, as well as an extruder capable of printing at 932 °F (500 °C), compared to the 752 °F (400 °C) of the basic version.

The Future of Extrusion Polymers

The 3D printing filament market has begun to explode since low-cost desktop 3D printers proliferated with the RepRap movement established in 2009. In addition to wood, metal and stone composites, which serve aesthetic purposes, a number of engineering-grade plastics have hit the market. 

While taulman3D has released a wide variety of nylon filaments, large chemical companies like Eastman, DuPont, Royal DSM and NatureWorks have jumped into the filaments space with their own materials to take a cut of the growing 3D printing materials market, which IDTechEx expects to pass the $8-billion mark by 2025.

The Strati concept car from Local Motors, 3D-printed with Techmer ES materials on the Cincinnati BAAM. (Image courtesy of Volim Photo.)
The Strati concept car from Local Motors, 3D-printed with Techmer ES materials on the Cincinnati BAAM. (Image courtesy of Volim Photo.)

Tom Drye, managing director of Techmer Engineered Solutions (ES), suggested that when it comes to polymer extrusion, the market will not be limited to filaments. Drye began exploring the 3D printing industry about five years ago, eventually leading the Techmer ES team to work with Oak Ridge National Laboratory (ORNL). Together with other partners, the team has 3D-printed a replica of a Shelby Cobra, a symbiotic Jeep, a shelter for off-the-grid living and the first 3D-printed car from Local Motors.

Drye pointed out that filaments originally allowed for a fine level of control and smoother finishes when 3D printing with plastics, but that the use of pellets may allow for the ability to 3D print with an even wider range of materials. 

Lonnie Love, group leader of automation, robotics and manufacturing at ORNL, seemed to agree. Love has been a key player in ORNL’s 3D printing projects, overseeing the development of the Big Area Additive Manufacturing (BAAM) machine manufactured by Cincinnati Inc. with technology licensed by ORNL.

For Love, 3D printing filaments have a number of limitations. “Most polymer extrusion systems use a filament as the primary feedstock,” Love explained. “This limits production rate—there are fundamental limits to how fast you can melt the filament—and material selection.  

“In addition, additive processes that are based on melting material continuously battle residual stress that leads to part distortion,” Love continued. “One solution is to print the part in a heated chamber or oven. However, we’ve worked with EPRI and shown that the oven for filament-fed systems accounts for approximately 90 percent of the energy required to make a part.” 

BAAM (Big Area Additive Manufacturing) Overview from Cincinnati Incorporated on Vimeo.

However, moving to pellets or powders over filaments will greatly increase the production rates, material selection and quality of printed parts.

“First, pellet-fed extruders can melt material at very high rates, far higher than filament-fed systems,” Love elaborated. “Going faster becomes a motion control, rather than a thermodynamic, limit. Second, the addition of fiber reinforcements—carbon, glass, bamboo—to the thermoplastic radically changes the behavior of the material. Not only does it increase material strength and stiffness but it also increases thermal conductivity and reduces the coefficient of thermal expansion to the point where you can print without the oven.”

As for the filaments that feature fiber reinforcement, Love said that the material ultimately becomes very stiff and brittle, making it difficult to spool. “With pellets, we’ve run up to 50 percent carbon fiber loading with no problem,” Love pointed out. “Finally, by going with a pellet, we leverage a huge supply chain: injection molding feedstock. Material options explode and costs drop.”

From BAAM to MAAM

ORNL and its partners have truly demonstrated the capabilities of 3D printing with pellets with the BAAM machine. With a build envelope of 7 ft x 13 ft x 3 ft, the BAAM system has a massive deposition rate of 40 lb/hr, which allowed Local Motors to 3D print a complete car chassis in less than two days. As Love mentioned, ORNL was able to do this with carbon-reinforced ABS plastic. 

Now that ORNL has teamed up with Cosine, we will see the creation of a Medium Area Additive Manufacturing (MAAM) machine. This process will involve augmenting the current capabilities of the AM1 3D printer, already able to print 10 pounds of plastic per hour, so that it can produce objects even more quickly.

Though the exact method for doing so has not been made public, Love described what he hopes to achieve with Cosine.

“Typical filament-fed systems produce parts at 1 to 5 cubic in per hour,” Love explained. “We see applications exploding if we can cross the 100- to 200-cubic-in-per-hour target. We are trying to help Cosine achieve an order-of-magnitude jump in productivity.” 

3D Printing Takes on Traditional Manufacturing

According to McCalip, upgrading the AM1 to a MAAM will enable Cosine to fill the niche between smaller industrial 3D printers and the Cincinnati BAAM. This will ultimately allow the company to take on the larger manufacturing space.

“Most of the revenue lies on the industrial side of things,” McCalip said. “I think that the way that this market is going to grow is that we’re going to start taking more jobs from the subtractive manufacturing world. Traditional manufacturing is a $100-billion industry and additive is only a small part of that. So, instead of us cannibalizing the additive market and stealing business from these other 3D printer companies, we’d rather show different use cases to be competitive against subtractive manufacturing.” 

This was the same sentiment that many at the recent RAPID show seemed to express. For instance, EnvisionTEC unveiled its own massive printer capable of 3D printing with composite materials. Cosine Additive is a small startup with the same goal in mind. The question is whether Cosine’s open platform, specialty hardware and thermal enclosure are enough to enable the company to become a threat to the traditional manufacturing space. With partners like ORNL, it seems that it might just be able to do so.

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