Until recently, buying a 3-D printer required a difficult choice: Get a heated-chamber system like the popular MakerBot, which prints durable, colorful pieces marred by ridges and pockmarks. Or go with a stereolithography printer, which produces seamless parts that fracture at the slightest application of force. Now Formlabs offers a third choice with Tough Resin, which creates smooth cyan chains strong enough to hoist cinder blocks.
Formlabs' recently released its second-gen printer, the Form 1+, a $3,300 aluminum-and-plastic pillar that prints hi-res models using photosensitive resins and laser beams. It might look like a clone of the $2,550 Form 1, which raised nearly $3 million on Kickstarter a few years ago, but the resin it uses is a primordial ooze from which almost anything can emerge. That's a big deal in the low-cost 3-D-printing market.
The SLA technology Formlabs uses binds each layer chemically. “The key ingredient in the resin is a molecule that starts out as long semi-flexible chain of atoms,” says company research scientist Alex McCarthy. “When we cure the resin during the printing process, these chains link up to form a solid network that is hard and rigid under normal conditions.” When a blunt object strikes a part made from the tough resin, the energy is absorbed and the part doesn’t shatter.
The results are impressive, according to technical data provided by Formlabs: Parts printed with the new resin suggest a higher-yield strength than other 3-D-printed materials. This is rare, but not unprecedented. Raney found some machines that could match or surpass the performance characteristics of the Tough Resin, but they cost well over $50,000.
Despite the strength, there’s no special sauce in the newfangled goo. “There’s no fiber or other particulate in the resin,” says Colin Raney, Formlabs' global marketing lead and a former managing director of design consultancy IDEO. “All the strength comes from the chemical formulation.” The only additive is a blue pigment, which helps differentiate it from other resin. This new material also introduces a new step to the process: printed parts require curing under a UV lamp for the resin to its full potential.
Tough Resin fills a critical gap in the SLA printer market. Formlabs’ original clear resin allowed for feats like printing a 50-foot-long chain inside a five-inch cube or creating intricate, fragile designs. A subsequent formulation made it possible to print robust, rubbery parts like tires but offered little rigidity. Making a printable plastic that’s durable while retaining high levels of accuracy has proven difficult across the industry.
“Most 3-D printed materials (and many plastics) are designed for strength, not toughness,” Raney says. “They can hold a lot of weight, but at some point, under enough force, they fail—and when they fail they snap or shatter.”
Design engineers had been clamoring for a material that would allow them to print functional designs like clips, clasps, and gears with enough resilience to take a beating. They wanted a material that could act as an alternate for ABS, the type of plastic Lego uses, while approaching the same slick finish. Now, they have that option for $175 per liter.
Formlabs has taken an unusual path in the 3-D printer market by developing the machines, companion software, as well as their own print materials. Most manufacturers work with plastics providers or labs to find suitable feedstocks, but Formlabs has decided to go “full stack.”
In Formlabs’ headquarters, lab coat-wearing scientists concoct samples of resin just feet away from where hardware designers spin printed circuit boards and software engineers code. The result is a collaboration where weaknesses in material science can be overcome with hardware, and vice versa. This is a huge advantage given the finicky nature of materials science, McCarthy says. “Say, you're working on a robot that keeps breaking because the bolts become loose overtime. That is something you can easily observe and fix. In a prototype resin, the screws are ten million times smaller and often transparent.”
Formlabs produces a relatively affordable high-accuracy machine for less than $4,000, but its dominance in that niche is in jeopardy. AutoDesk released schematics and a reference design for a 3-D printer with similar specs, making it easier for low-cost manufacturers to get to market. Well-funded competitors like Carbon3D promise to match Formlabs’ print accuracy while increasing speed.
Formlabs believes that producing a protean array of plastics, exclusive to their system, can help them maintain a lead, Raney says. “Now you can go from printing beautiful, delicate figurines to printing a hammer that will literally drive nails by just switching materials.”
