In 2014, a small start-up shook SOLIDWORKS World with a game-changing technology capable of reinforcing nylon 3D-printed parts with continuous carbon fiber. Markforged, out of Cambridge, Mass., demonstrated that for about $5,000, any machine shop, manufacturing facility or lab could produce carbon fiber–reinforced parts on-demand.

The Mark X is the new fiber reinforcement 3D printer from Markforged. (Image courtesy of Markforged.)

The company has since upgraded its system with the Mark Two 3D printer and released a number of new materials, including Kevlar reinforcement and a chopped carbon fiber-nylon composite. Now, however, Markforged aims to change the 3D printing game once again with a new printer dubbed the Mark X

ENGINEERING.com spoke to Markforged CEO and Founder Greg Mark, as well as Cynthia Gumbert, vice president of marketing for Markforged, about the new printer.

Continuous Filament Fabrication

Markforged refers to its 3D printing technology as continuous filament fabrication (CFF) because while one print head 3D prints a thermoplastic, the other head lays down continuous strands of fiber reinforcement material. When Markforged launched with the Mark One 3D printer, the thermoplastic used to print the body of a part was nylon and the reinforcement material could be carbon fiber or fiberglass.

The Mark Two 3D printer from Markforged. (Image courtesy of Markforged.)

The use of continuous strands of carbon fiber allows for incredibly strong, yet lightweight parts. In fact, carbon fiber reinforced objects made with CFF have a higher strength-to-weight ratio than aluminum and are up to 27 times stiffer and 24 times stronger than the ABS plastic often used in 3D printing. At the same time, because these components can be made on a desktop machine with a price of only $5,499, it becomes possible to create custom reinforced parts on-demand with very little overhead.

Over the past two years, Markforged has expanded its materials portfolio, improved its software and released the faster, more accurate Mark Two 3D printer. Reinforcement feedstock grew to include Kevlar and high-strength, high-temperature fiberglass as well as a new carbon fiber-nylon composite material called “Onyx,” which added even more strength to composite parts.

An image showcasing the carbon fiber laid within a 3D-printed part. (Image courtesy of Markforged.)

The chopped carbon fiber within Onyx makes the material 3.5 times stiffer than the company’s standard nylon. The nylon, however, makes the material tough and wear resistant as well. Onyx also has a heat deflection temperature of 145 °C.

All of this lays the foundation for the Mark X, a CFF printer capable of the output, surface finish and quality control necessary for batch manufacturing.

The Mark X

The look of the Mark X is familiar, except for two immediately striking differences. In addition to an integrated cabinet with dry box and storage, the Mark X has double the print area on the XY-axis and 2.6 times the volume, measuring 330 mm by 250 mm by 200 mm (13 in x 9.8 in x 7.9 in). This means that the system can produce much larger parts, as well as batches of smaller parts.

The Markforged is bigger, more precise and has built-in quality control mechanisms. (Image courtesy of Markforged.)

At the same time, the precision of the machine has been further increased. With stiffer Z-axis rails, the Mark X gantry is two times flatter. The motor encoders, silent drive and other features add further accuracy.

While the Mark Two is capable of printing features as fine as 100 microns, the Mark X has been pushed to print 50-micron layers. This allows for a level of refinement that rivals injection molding so that not only are parts stronger and lighter than non-reinforced components, but they look finished as well.

This drone has been 3D-printed on the Mark X, though the features are so fine that many 3D printing experts don’t immediately realize it, according to the Markforged team. (Image courtesy of Markforged.)

High throughput, improved strength and fine detail are all essential for 3D printing to compete with traditional modes of production. However, the upgrade that may make the Mark X the X that marks the spot is its in-process quality control.

In-Process Quality Control

The Mark X has a built-in laser on the print head which actually scans parts as they are printed. With 1-micron resolution on the Z-axis and 50 microns on the X and Y, the laser allows users to match parts being printed against the original CAD file.

A laser is built into the printhead of the Mark X in order to ensure quality parts are produced. (Image courtesy of Markforged.)

In Figure 1, captured with the built-in micrometer laser while a motorcycle brake lever was printed, the white lines represent the toolpath that the print head took when extruding plastic, how the plastic was supposed to be laid down. The green area is where the plastic is actually laid down, the blue represents layers ten microns above the current view and the red represents ten microns below. In the upper right corner of the image, you’ll see a number of CAD measurement tools that allow the user to get the radius, perimeter and area of a portion of the printed part.

Figure 1. Built-in quality control allows users to examine a part during the printing process or after it’s been completed to match it against a CAD model. (Image courtesy of Markforged.)

Upon release, this feature enables what Mark called “human loop inspection,” in which a machine operator can manually match the printed part against specifications and decide to stop a print midway through if a problem arises. In about a year, however, Markforged plans to release closed-loop control that will rely on a set threshold of tolerance to correct offsets and other imperfections during the printing process via software or mechanical adjustments. If the print happens to go beyond this threshold, the print will automatically be aborted and the software will notify the machine operator.

Mark pointed out that this technology is not yet implemented in 3D printing, nor in manufacturing at large. Fabrication equipment relies on open-loop control, with manual intervention based on machined feedback a necessary part of the manufacturing process.

“Everything in mechanical engineering is open-loop,” Mark explained. “You CAD a part and you have this specification that you want to hit. Whether you’re 3D printing, CNC machining, injection molding, or your casting, take your pick—these are all open-loop processes and then a secondary, external process gives you feedback to allow you to correct the situation. Even in this first software release with the Mark X, we’ve combined this external process with the manufacturing so that you can run real-time analysis while you’re manufacturing.”

Mark added, “What we’ve done here is the first mechanical engineering process where there’s closed loop. While we’re in the manufacturing process, in our case it happens to be 3D printing and it happens to use carbon fiber, you have this in-process inspection laser that lets you monitor the dimensions, the tolerance, the part, both while you’re building it and when it’s done.”

For the time being, this in-process quality control will be limited to the Mark X and 3D printing, but Greg Mark hasn’t ruled out introducing the technology to other manufacturing processes. When asked whether Markforged would sell the laser setup separately for other fabrication systems, Mark responded, “It’s all under consideration. We’ve been so busy trying to make printers fast enough that we haven’t put much thought into that yet, but it’s something that we’ve certainly talked about.”

As for new materials, Mark said, “We’re always working on new materials. It’s constantly in the pipeline. And the X has been designed to handle some of the new materials that we’re going to come out with.”

Release Date, Pricing, and More

The Mark X is already shipping, so customers can head to the Markforged website and purchase one immediately. At $69,000, the price may not be quite as low as the Mark One and Mark Two, but Markforged suggests that the Mark X is still competitively priced, especially given its capabilities.

For instance, traditional fused deposition modeling from Stratasys starts at a price of about $45,000 and reaches as high as $400,000. Moreover, those machines are neither capable of fiber reinforcement nor in-process quality control.

A wrench 3D-printed with the Mark X. (Image courtesy of Markforged.)

Part of the reason for this price is the fact that the Mark X will be used for serial production. Gumbert explained, “The thing that’s been very exciting with some of our large customers is the notion of totally reworking their supply chain. Instead of having millions of parts in inventory, you could basically print parts as needed. This has basically been the dream of 3D printing, but until now, 3D printing hasn’t had the technology to give you high strength, beautiful surface finish and great precision.”

Gumbert added, “We’re networked, we’re cloud-based. We can have 20 printers running and controlled through a single portal at a production facility. We can replace small-run production or mass customization production of end use parts. This is a real industrial-scale machine and we’re not talking about ourselves as another 3D printer. This is a real new production machine that can’t be made this cheaply, this precise by other means. A lot of our customers will come up with ideas that we haven't thought of yet.”

Existing Markforged customers will be excited to know that from now until March 2017, they can purchase a Mark X at a big discount. Markforged is selling the Mark X with an “Innovators’ Appreciation Offer,” with which anyone who has purchased a Mark One or Mark Two will be able to purchase the Mark X and be refunded the original price paid for their original machines. That means that someone who purchased the Mark Two Enterprise Kit for $13,499 will receive $13,499 off of the price of the Mark X. On top that, they will get to keep their original machine.

Of the offer, Greg Mark said, “Early adopters get things when people don’t. They take a chance. This is an opportunity to thank for them.”

Gumbert added, “We’re calling them innovators too because they’re finding new applications for our printers and we’re giving them access to the X at a discount so that they can continue on that path of using our printers for interesting and great things.”

To learn more about the Mark X, you can check it out on the Markforged website and request more information.