Tool Tales

Sep 01, 2023

Over the past 30 years, the 3D-printing industry has delivered innovation after innovation. Stereolithography (SLA), fused deposition modeling (FDM), selective laser sintering (SLS) and direct metal laser sintering (DMLS). These are just a few of the technologies that have changed the way we design, produce and procure parts, earning their inventors a special place in the annals of additive manufacturing (AM) history.

Here comes another. Fortunately, there’s no catchy acronym to learn and remember. At first glance, this novel AM technology might not seem terribly different from some of the other 3D-printing methods that have sprung up over the past decade, but this AM newcomer bears several distinct advantages over its nearest competitor.

Steve Connor & Ted Sorom, AM Startup Technology Award Winner, Co-founders, Mantle Inc.

It’s called TrueShape, and it promises to do to toolmaking what 3D Systems Inc. founder Chuck Hull did to prototyping in 1984, when he filed for a patent on his “Apparatus for production of three-dimensional objects by stereolithography,” then introduced the world’s first commercial 3D printer—the SLA-1—a few years later.

Ted Sorom and Steve Connor have embarked on a similar path. The two co-founded San Francisco-based Mantle Inc. in 2015, spent the next five years developing a hybrid 3D-printing and machining solution, and have since deployed either printed parts or full systems at dozens of tooling companies and partner firms; among them Nicolet Plastics; Fathom Manufacturing; plasma cutting equipment provider Hypertherm; and several leading medical device providers.

These and numerous other manufacturers are said to have shaved weeks and sometimes months off their development cycles, produced millions of parts with TrueShape-printed mold inserts and cavities, and cut their operating costs by 50% or more, all without sacrificing part quality or requiring significant design changes. “The status quo of plastic injection moldmaking hasn’t changed since the 70s, when EDM (electrical discharge machining) first became commercially available,” says Sorom, who serves as Mantle’s chief executive officer. “Our technology presents an opportunity to significantly alter the course of a monolithic industry that touches practically every aspect of our daily lives.”

Monolithic might be an understatement. The global tooling market for plastic injection molding alone is $45 billion, with $8 billion of that in the United States. Add to that the countless other components made of hardened tool steel produced each year and it’s easy to understand why Mantle’s claims that it will soon “change the face of manufacturing” should not be taken lightly.

It’s for these reasons that the Society of Manufacturing Engineers (SME) recently honored Mantle with its annual AM Start-Up Technology Award, which recognizes entrepreneurs who’ve developed a unique technology or application of existing technology, one that solves an existing problem, can be demonstrated or is feasibly sound, and has the potential to serve a large or niche market.

Mantle met each of these criteria handily and, as part of the application procedure, presented a thorough, well-written presentation to the SME board. “As many in the industry have noticed, there are a fair number of me-too technologies out there today,” explains Ethan Rejto, Mantle’s director of marketing, who helped create the award-winning documentation. “We’re delivering a solution for a specific market area that others can’t touch.”

Connor is Mantle’s chief science officer. He says that the TrueShape process begins with a metal paste filled with H13- or P20-equivalent tool steel powder. This proprietary material is extruded “FDM style” onto a build plate and quickly dried with an infrared light source after each layer, removing the paste’s liquid carrier and leaving behind a metal compact containing a trace amount of binder.

Here’s where the hybrid piece of the TrueShape equation comes in. Because Mantle’s P-200 printer is built on a true machining-center platform, cutting tools can be engaged during any stage of the build process. Doing so removes the stair-stepping effect common to all 3D printers while greatly increasing part accuracy and delivering “butter smooth” surface finishes. Since the metal compact is still soft at this stage, feed rates are “about 10 times faster” than when machining traditional tool steels, with virtually no tool wear to boot.

With the build complete, the green part is placed into Mantle’s F-200 furnace for sintering, during which the mold insert or other tooling component achieves a Rockwell hardness level in the 40s and can later be hardened into the low 50s. “In many cases, the parts are ready for production once they leave the furnace,” Connor says.

For those that aren’t, some light polishing, surface grinding or sinker EDM work is all that’s required. “We have a customer that made a latch for a laptop holder for use in emergency vehicles,” Sorom says. “They were able to eliminate an inordinate amount of processing time and deliver weeks ahead of schedule, with commensurately lower costs. In this and many other instances, TrueShape removes two-thirds of the processing that would normally be needed to deliver a tooling component. In addition, we can create conformal cooling channels so easily and cost-effectively that it has many moldmakers rethinking their design strategies.”

AM practitioners familiar with binder jet might be hearing mental alarm bells right now. “What about shrinkage?” they’re thinking, the bane of many such “print and sinter” AM processes. Sorom hears these arguments often. He noted that the decades-old metal injection molding (MIM) technology generates shrinkage rates of 25%, with binder jetting slightly under that. Mantle-produced parts, he pointed out, shrink much less than either.

“Getting a good part out of the furnace is a bit of a dirty secret for these various sintering technologies,” Sorom says. “You might get a really great print, but the final results will be less than desired unless you can accurately predict and minimize shrinkage. We take a number of steps to avoid this. For starters, we ensure that part density is as high as possible during the build. We also choose our powders and binding material very carefully, use a unique, multi-stage sintering process, and our software does a great job at managing potential problem areas. Because of all this, our parts shrink a maximum of 9%, less than half of anyone else in the industry. As a result, we can achieve plus or minus 25-micron accuracy (+/- 0.001”) in the first inch, with roughly another 25 microns for every inch thereafter.”

Shrinkage is important, but so is usability. Machinists reading this might wonder about the challenges of generating toolpaths in the middle of a 3D-printing process. Not to worry, Sorom notes. In addition to automating much of the build preparation, the software generates all of the machining toolpaths and tool selection so no CAM programming is required.

“A toolmaker who was interested in our solution visited our facility,” he recalls. “He and his team had heard stories about the huge number of parameters and settings associated with many 3D printers, and when you throw machining into the mix, they figured it would be crazy difficult. So, we walked them through the programming and operation and proved to them that practically anyone can run this machine. It wasn’t long after they left here that they placed an order.”

Results like these are not surprising for Sorom. He worked as a mechanical engineer on everything from consumer product design to lighting systems for filmmakers and television crews. He launched his first startup company, an international payment service, while attending business school at University of California, Berkeley. When he met Connor, who had attained his PhD in nanomaterials from Stanford a few years earlier, Sorom decided that his next venture would deliver products that “would hurt if you dropped one on your foot.”

Mission accomplished.

As their recent award describes, Mantle and its technology is still considered a start-up. There’s plenty of time to think about the future, but one thing is certain: the TrueShape process offers manufacturing possibilities well beyond molds and other forms of hard tooling, including end-use components for the medical, aerospace and defense industries. But for now, at least, Sorom, Connor, and the rest of the Mantle team have their hands full. “We’ve spent the last seven years developing a system that more efficiently produces the tools that produce the parts that are all around us,” Sorom says. “Furthering that technology will keep us busy for some time to come.”