Tech Talk

A company recently created the first 3D-printed metal bike frame.     Photo: Courtesy of Renishaw

3-D Printing’s Renaissance

Bikes, boats, and boards have started coming off a printer rather than an assembly line. And that could mean better, less expensive gear for you.

For a 30-year-old technology, 3-D printing is having a heck of a renaissance. The past few months have pushed the manufacturing technique to the front of the outdoor gear world, with innovative tinkerers producing whole products—a kayak, a working full-suspension mountain bike—using 3-D printers.

The natural question: how long before the bikes, boats, and boards we play with come off a printer rather than an assembly line? Could your next pair of skis come hot off the press, maybe even printed at home with layers of chatter-killing carbon fiber, laser-sintered metal edges, and a custom topsheet graphic, of course?

3-D printing—or, more accurately, additive manufacturing—is exactly what it sounds like: making a three-dimensional solid object from a digital source file. Traditional machining or forging techniques create objects by milling, cutting, or stamping materials into the finished shape. Injection- or clamshell-molding often relies on expensive machinery that’s specific to each part or product.

Additive manufacturing, by contrast, “prints” very thin layers of a base material to build the object. With the right software, printer, and material, you can create an almost infinite number of shapes.

Outdoor gear companies have been using 3-D printing for years. What’s changing is how they use it. About four years ago, companies used 3-D printing primarily to make mockups for sales and marketing, or for designing graphics. Now, the focus is on function. 

Confluence Watersports (parent brand to boat companies including Dagger, Wave Sport, and Perception) uses 3-D printing to design parts, such as handles, to test on boats before they enter production.

Before Confluence began using 3-D printing, testing something as simple as a different O-ring would involve an injection-molding subcontractor and weeks of turnaround time. Now “you can print in a few hours, install it on a boat, and test it the same day,” says Project Engineer Luis Fernandez.

Snowsports giant K2 uses 3-D printing to check fitment on complicated binding parts and helmet and goggle components. Bike maker Specialized uses 3-D printing for a variety of purposes, including to make bike frames or parts for aerodynamic testing in its in-house wind tunnel (an industry first).

Most aerodynamic analysis takes place virtually, in computational fluid dynamics (CFD) software, but “with 3-D printing we can take the top three or five iterations from CFD into the actual tunnel to see which is fastest,” says Product Design Engineer Matt Urquhart.

It’s not just big guys taking advantage of the cutting-edge technology. Chris Williams, Managing Director at Empire Cycles, says that part of the company’s goal in making its 3-D-printed MX6 prototype frame was to hone traditional manufacturing. A computer design process called topology optimization gave them an efficient shape for a crucial part, the frame’s seat mast, which cut weight by 40 percent. 3-D printing allowed them to actually make the part and test it before creating expensive tooling.

So, will we one day print our own frame at home? It’s not as far off as Jetsons-esque flying cars, but don’t expect to skip the bike shop anytime soon. Fundamentally, the technology exists, says Ping Fu, Chief Entrepreneur Officer at 3-D Systems, the company that invented 3-D printing back in 1983. “Most of the obstacles are cultural, not technical,” she says.

Just a decade ago, 3-D printing was only offered in a few basic plastics. Today, there are over 100 materials—plastics, yes, but also metals and composites. Empire’s bike was produced via a technology called Selective Laser Sintering, where a laser superheats powdered metal (here, titanium) to fuse it, layer by layer, into a solid object. A new startup, MarkForged, says it has created the world’s first 3-D printer that can print shapes in continuous-thread carbon fiber.

And, says 3-D Systems’ Fu, there’s a major opportunity for 3-D printing in customization. Some day soon, she predicts, you may get a 3-D scan of your foot at a high-end bootfitter, who will use the 3-D printer to make a custom ski boot liner. That’s not to mention those personalized topsheet graphics.

But manufacturers often resist moving away from traditional production, in part because of the significant investments already made in factories. The consumer market is underdeveloped, Fu says, because people are unfamiliar with it. 3-D printing has no real place in the U.S. educational system, so the maker movement is the primary driver of knowledge. "A community college would be a great place for people to learn [additive manufacturing]," she says.

Cultural obstacles aside, two major hurdles remain: cost and complexity. MarkForged’s basic carbon material is about seven times the cost of its nylon product. And an SLS printer that can make a product like Empire’s frame costs in the mid-six figures. (Empire enlisted a partner, Renishaw, to create the frame.)

Costs for materials and machines should decrease, and probably quickly, but for the foreseeable future, roto-molding will still be the more affordable way to make kayaks than printing them.

More problematic is complexity. Metal alloys often must be heat-treated for long-term durability, a step that can’t be done yet in 3-D printing. And carbon fiber composite is a diverse material used in intricate ways that printers have not mastered.

A carbon composite bike frame may contain as many as 500 individual sheets of fiber of various grades, arranged in a highly specific sequence and orientation in the mold, called the layup process. It’s labor intensive and has yet to be automated. 

“You could potentially produce a rideable frame (using 3-D printing),” says Andrew Juskaitis, global senior product marketing manager for Giant Bicycles, the world’s largest maker of carbon composite bikes. “But all the intrinsic qualities that make a carbon fiber composite frame ride the way it does, we can only achieve through layup.” And we're not there yet.

In the next decade, 3-D printing will undoubtedly grow and may come to replace conventional manufacturing in some areas. (It’s already a major production technique in the medical device field.) And, unlike flying cars, the building blocks for bigger transformations are already there. We can see it, but we just can’t quite get there yet.

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