Seven Robotic Arms Lifting 3D Printing into Industrial Manufacturing

Now that the hype around consumer 3D printing has more or less died off, the true potential of additive manufacturing (AM) in the larger production supply chain is starting to be realized. While this takes many forms, from advanced metal 3D printing technologies to fiber composite systems, one trend that is worth its own consideration is the use of industrial robots in 3D printing.

Known for their work in picking, placing and assembling such massive and complex objects as automobiles, industrial robotic arms are now commonplace in mainstream manufacturing due to their scalability and flexibility, but only recently has the technology begun to present itself in 3D printing. Here we note seven different 3D printing platforms that leverage the adept skills of industrial robots to make AM a more suitable fabrication method for the larger manufacturing supply chain.

After a troubling couple of years under its previous CEO, 3D Systems has worked to reinvent itself in 2016, taking on HP veteran Viyomesh Joshi as its new chief executive and unveiling a new 3D printing system that aims to make AM a truly industrial technology.

Figure 4 gets its name from the original patent filed by 3D Systems Cofounder Chuck Hull for stereolithography (SLA) in 1984. While most SLA systems rely on a UV laser—or, in the case of digital light projection (DLP), a UV projector—to cure photopolymer resin, the Figure 4 setup introduces a couple of interesting twists.

For one, Figure 4 uses a continuous DLP process in which a thin membrane between the UV projector and the vat of resin enables a fast, layerless 3D printing process. The technique, originally invented and patented by Carbon, can produce prints with isometric strength, meaning that the fibers that make up a print layer are equally strong in every direction. This contrasts with the typically weak Z-axis of most 3D printing processes.

While this speed and strength is necessary in industrial manufacturing, the Figure 4 setup also implements several robotic arms to perform some of the manual processes associated with 3D printing. The scalable system sees one robotic arm transfer detachable printbeds to and from the aforementioned DLP 3D printer such that, once a print is complete, it can move the finished object and printbed to a post-processing station and move a new, empty printbed into place for a subsequent print to begin.

Meanwhile, another robotic arm can pull a print from a post-processing station, where the object undergoes further UV curing and cleaning, and send it to validation and inspection. In this step, an overhead scanner can 3D scan the part and match the data against a standard CAD file to ensure that the part has been printed properly.

Altogether, the process demonstrates a workflow in which industrial robotic arms can be implemented to perform an increasing variety of tasks related to the printing process, from fabrication all the way up to inspection. By showcasing all of these abilities, 3D Systems makes it possible to imagine a Figure 4 setup, or multiple Figure 4 stations, used to execute an automatic factory, ultimately doing away with the time, speed and labor constraints previously associated with 3D printing.

Industry leader Stratasys has also showcased new industrial 3D printing technologies that extend the capabilities of the company’s fused deposition modeling (FDM) on which it was founded. At International Manufacturing Technology Show (IMTS) 2016, Stratasys unveiled two new technology demonstrators that rely on industrial robotic arms: the Infinite-Build and Robotic Composite 3D Demonstrator.

The Infinite-Build 3D Demonstrator is so called because the system is capable of 3D printing objects of hypothetically infinite lengths. Unlike Stratasys' previous Fused Deposition Modeling (FDM) printers that extrude thermoplastics onto a horizontal plane, the Infinite-Build system “turns the traditional 3D printer concept on its side” to print onto a vertical plane that can be expanded during the printing process.

To speed up the FDM process, the extruder of the system uses plastic pellets, rather than filament, which are fed into a three-pound hopper and sent to a micro screw extruder capable of printing 20,000 micro-cubic inches per second of material within a sealed heated chamber. As a result, the Infinite-Build 3D Demonstrator can print about 10 times faster than existing FDM technology and consumes about one pound of material per hour.

The industrial robotic arm comes into play to refill the hopper attached to the system, grabbing new batches of feedstock and pouring them into the hopper. As the extendable printbed travels off into the theoretically infinite Y-axis, the robotic arm can continuously fill the machine with new pellets.

The process was used to 3D print a 16-foot-long piece of intricate ductwork, among other things, to demonstrate the possibilities of the technology. With the help of Ford and Boeing, the Infinite-Build Demonstrator was designed for such industrial applications as aerospace and automotive.

Perhaps more interesting in its use of industrial robots is the company’s Robotic Composite system, which pairs a six-axis industrial robotic arm with a two-axis robotically controlled print platform to create an eight-axis FDM printer capable of fabricating objects from just about any angle. The robotic arm is outfitted with an extruder to print onto the rotating platform, making it possible to produce objects with limited support structures or to modify existing objects with printed material. Given the freedom of the flexible robotic arm, the system could also reduce the Z-axis weakness associated with traditional layer-by-layer manufacturing, opening up new material strength possibilities as well.

The Robotic Composite 3D Demonstrator can, like the Infinite-Build 3D Demonstrator, use plastic pellets, or it can use filament. While the system was showcased 3D printing a nylon-carbon fiber composite, one can imagine electronic circuits being printed in a similar way as a product makes its way down an assembly line.

The Woburn, Mass., company Viridis3D, a somewhat earlier adopter of industrial robotic arms for 3D printing, unveiled the fruits of its R&D work in 2015 with the RAM 123 3D printing system. The company was founded by Jim Bredt, previously the cofounder of ZCorp, which invented the popular and colorful binderjetting process acquired by 3D Systems. Binder jetting has also been licensed to ExOne and Voxeljet for 3D printing sand and metal.

Viridis3D’s robotic additive manufacturing (RAM) platform, however, takes this binderjetting technology out of the box. RAM uses an ABB industrial robotic arm with an inkjet head to swing back and forth and deposit layers of sand and liquid binder onto a print platform. The sand is gradually fused together at a rate of three vertical inches per hour until the object is complete.

While the RAM123 has a build volume of 12 in x 24 in x 36 in, Viridis3D has also demoed the larger and faster RAM260. 3D printing sand in this way presents a scalable platform for producing custom, geometrically complex sand molds and cores on demand, while also reducing the need for sand mold inventory. These prints can then be used to cast metal objects at a lower cost compared to other techniques.

As a relatively new company, Viridis3D has only just entered the market, but the firm has partnered with an established leader in the industry, EnvisionTEC, for further development of the RAM process.

French start-up XtreeE, for instance, outfitted an IRB8700 robotic arm from ABB Robotics to create a massive concrete 3D printer capable of extruding complex geometric structures as tall as 14 m. Most recently, the firm showcased its efforts thus far, unveiling a concrete pavilion inspired by nature.

Unlike the boxy setups associated with other additive construction firms like D-Shape and WinSun Global, XtreeE’s process has a much greater freedom of movement thanks tothe use of an industrial robotic arm. Due to the use of quick-setting, high-performance concrete, the technology may enable the creation of more geometrically complex structures that don’t require as much secondary support.

Upon 3D printing the XtreeE Pavilion, the firm will work to construct a functional building in the next 18 to 24 months.

U.S. firm Branch Technology has applied its own unique take to additive construction, with Founder Platt Boyd aiming to use as little 3D printing in the process as possible. Instead of 3D printing the final building material, Branch Technology actually 3D prints an interior lattice structure from a thermoplastic composite and then sprays insulation and concrete onto the scaffold, resulting in a lightweight yet strong wall that can be shipped to a construction site.

 Unlike the stationary ABB arm from XtreeE, Branch Technology mounts large-scale KUKA arms onto a 10-meter-long rail system to create prints up to 25 feet wide by 58 feet long. This makes the Branch Technology platform possibly the largest free-form 3D printing system in the world. The strategy to 3D print complex, interior lattices may also drop the cost of additive construction.

Branch Technology has so far demonstrated its process with small-scale proofs of concept and large lattice structures without foam or concrete, but has yet to construct load bearing walls with this approach. However, it is in the process of building a crowdsourced home in Chattanooga, Tenn., where Branch Technology participated in the town’s start-up incubator GIGTANK.

Branch Technology and XtreeE are not alone in using robotic arms to 3D print large structures. Possibly the most famous implementation of this technology comes from a Dutch firm called MX3D. After developing a polymer-based method for extruding free-form resin structures, designer Joris Laarman went on to apply the same approach to metal welding and found MX3D.

MX3D feeds metal wire to an arc welder mounted to an ABB robotic arm, slowly fusing the metal bit by bit into a free-form, freestanding structure. The start-up, which has partnered with Autodesk, Delft University of Technology and others, made headlines when it announced that it would be 3D printing a steel bridge that would span one of Amsterdam’s famous canals.

Despite being announced over a year ago, the bridge has not yet been completed. In the meantime, however, MX3D has used its unique metal 3D printing technology to create several projects, such as a 3D-printed bronze sculpture, a steel bench and a bicycle.

Whereas earlier projects seem to have required printing objects in several parts and fusing them manually, the most recent piece, a bronze butterfly sculpture, seems to have been printed in one piece, perhaps evidence that the bridge may be on the horizon.

Some of the technologies mentioned here have only just been unveiled, such as those from Stratasys and 3D Systems, and there may be plenty more to come. A variety of projects aim to implement similar robotic systems for use in 3D printing, from large companies to design students at universities.

German industrial control and automation company Festo, for instance, has developed a novel process for fusing resin and glass fiber into lattice structures. As a demonstrator for Festo's EXPT-45 robot, the 3D Cocooner weaves structures almost like a spider, without the need for any support structures.

Other initiatives include the Collaborative Glass Robotics Laboratory that uses an ABB robot to swivel a moving platform beneath a machine that melts glass to create imperfect glass objects. Students at the Institute for Advanced Architecture of Catalonia used an industrial arm to extrude clay. And multiple start-ups, like Makerarm and Carbon Robotics, are in the process of releasing small-scale robotic arms for various forms of desktop fabrication.