Entrepreneurs and existing manufacturers are making 3D printers that automate production of composite parts, and are unique in their design.
Behind the push for ways to automate and scale composites production is the quest to lightweight transportation on the roads and in the air. Lighter vehicles use less fuel and reduce carbon emissions, and those made with composites have the added benefit of being corrosion-resistant.
There’s another benefit, too.
“3D printing composites can eliminate the need for a mold in many, many cases,” said Tim Schniepp, business development director for composite tooling at Stratasys (Eden Prairie, MN). “This can save time and money.”
The downside is that some composite materials aren’t particularly conducive to 3D printing, such as fiber-reinforced thermosets, Schniepp said.
In addition to Stratasys, whose robotic composite 3D demonstrator prints nylon reinforced with short carbon fibers, SME talked with Arevo Labs (Santa Clara, CA), EnvisionTEC (Dearborn, MI), and Impossible Objects (Northbrook, IL), and checked out online a desktop model by Markforged (Cambridge, MA) to learn about their technology and how they envision its use in manufacturing.
Here’s what we learned.
When Arevo’s CEO Hemant (the “t” is pronounced “th”) Bheda was president and CEO of Quantum Polymers (Newark, DE), an OEM asked him to manufacture a composite material with high mechanical properties that required precise control over the orientation of every carbon fiber in it.
“I said it was impossible with current manufacturing processes,” said Bheda, who sent the OEM’s representative on his way. “A few months later, it clicked that 3D printing was the solution.”
A year later, Arevo arrived with a deposition head with advanced thermal management technology that deposits thermoplastic composite materials and can be attached to any articulated robotic arm, liberating 3D printing from a boxed-in platform. The head accomplishes true 3D deposition vs. today’s technology that limits deposition on the X, Y plane.
The magic is in his software: Arevo’s finite element analysis algorithm “evaluates part geometry, material properties, hardware capabilities and tool path orientations” to get maximum strength by controlling the orientation of reinforcement fibers in 3D space. Arevo’s materials include PEEK, PAEK and PARA-based composites reinforced with carbon or glass fiber and carbon nanotubes.
“What excites us is using this technology for production parts,” Bheda said. “Our goal is to make parts with unique properties that cannot be made with traditional manufacturing, such as injection molding.”
A vision for composites
While Arevo decided to go big with its out-of-the-box design, EnvisionTEC has its sights set on making smaller parts such as composite brackets and control surfaces, among others.
“We’re not talking aircraft wings, but parts,” said COO John Hartner. “The idea here was to work with all the pre-pregs the customers were used to.”
EnvisionTEC’s machine, which Hartner expects to be in beta testing in December and on the sales floor starting in the first quarter 2017, uses pre-preg mesh or polymer on rolls up to 48 inches wide. Inside the machine, grippers pull the material from a pre-heat chamber across the work area. In the build space, an inkjet head dispenses anti-laminating fluid where necessary, and an infrared heater capable of a maximum 735 degrees Fahrenheit, along with a heated, pressurized roller, laminate the layers. The worktable rotates to make the fibers multi-directional.
An ultrasonic cutter traces the outline of a part, which is subsequently pushed out of the source material.
Hartner said the machine makes parts faster because there’s no need to make a mold, which also reduces cost. It also eliminates the need for post-processing.
“We have very good accuracy, 100 microns,” he said. “We think we can even get tighter.”
EnvisionTEC’s materials include carbon-reinforced PEEK for defense and aircraft parts and polycarbonate with fiberglass for yachts and all-terrain vehicles.
“We’re creating all the recipes for materials at both ends of the spectrum,” Hartner said.
Making the impossible
Like Hartner’s company, Impossible Objects is looking at shipping its machines starting in 2017, said CEO Robert Swartz.
The machine uses a non-woven carbon fiber sheet for each layer of a part. A water-based solution is “printed” using thermal inkjets onto each sheet, and then polymer powder is applied that sticks to the solution. The sheets are stacked, heated to melt the polymer and evaporate the solution, and compressed. The part’s net shape is achieved through mechanical or chemical post-processing.
Swartz said that one of the key insights in his machine’s design is to forgo the use of a print head through which complicated material like melted fiber-reinforced polymer has to be dispensed.
The tensile strength of his carbon fiber-reinforced, high-density polyethylene is up to 10 times stronger than that made with other 3D printing technologies, according to Impossible Objects’ web site.
Like Bheda, Swartz’ objective is to compete with injection molding for making parts. Until Impossible’s machines are ready to ship, clients can order parts made of carbon fiber, Kevlar and fiberglass-reinforced composites made with a range of thermoplastics.
Swartz sees uses for his technology in industries as diverse as aerospace (for drones and satellites), athletics, automotive (for tooling and light-weighting vehicles), aviation, general industrial, health care, marine, and robotics.
Forged at MIT
The web site for Markforged touts its dual-head Mark Two printer, introduced earlier this year, as an affordable industrial technology for making tools, fixtures and prototypes as well as end-use parts.
“After introducing the world to continuous fiber-reinforced printed parts, we wanted to focus on perfecting the experience with a MarkForged printer,”
Greg Mark, founder/CEO and an MIT aerospace engineer, said in a press release announcing the second generation of his technology. “The Mark Two enhances the overall MarkForged experience and means our customers get stronger parts in their hands, faster than before.”
The Mark Two makes carbon fiber; fiberglass; high-strength, high-temperature fiberglass; and Kevlar-reinforced nylon parts. The company’s newest material, Onyx, is nylon reinforced with micro-carbon fibers, and is stiffer, more heat tolerant and more dimensionally stable than other plastics used for 3D printing, according to the company’s web site.