There’s a small garage at the intersection of Route 7 and Columbiana Waterford Road in Fairfield Township, Ohio. It’s unremarkable in appearance and passersby wouldn’t give it a second glance. Yet, this humble block building serves as the birthplace of what is said to be the largest manufacturer of 3D-printed sand cores and molds in North America—and perhaps the world.
Mark Lamoncha, president and CEO of the company now known as Humtown Products, explains that his father Russell opened a pattern-making shop there in 1959. “His former employer had a strict ‘no talking’ rule at work,” he laughs. “It bothered him and a coworker so much that they eventually quit and went into business for themselves.”
Rumor has it that the Hum family moved to South Carolina soon after, although a dozen or so of their ancestors remain in Ohio—the Hum Cemetery sits a quarter-mile north of that old garage. Regardless, the elder Lamoncha took the pattern-making ball and ran with it, and the place where he spent so many hours is now surrounded by a handful of much larger buildings, the daily destination of several dozen dedicated team members. This is Humtown Products.
Lamoncha notes that a great deal has changed since the day his father—who has since passed on—started the company. As you’ll see, that’s a gross understatement. Like most manufacturers, Humtown has endured its share of ups and downs, including a crippling downturn during the 2008 market crash that nearly bankrupted the company. This led Lamoncha to rethink the traditional employment model in favor of one that would motivate his workers while also giving them an opportunity to grab a bigger slice of the pie.
The result was Humtown’s now patented “Visual Earning System,” which is described as a “real-time process of measuring and showing team members their rate of productivity.” In fact, according to the company, the approach has delivered up to four-fold increases in throughput, along with a more engaged and satisfied workforce. But it’s a more recent development that has given Humtown bragging rights to the “world’s largest” title.
“We first saw the technology at the 2014 RAPID + TCT conference,” Lamoncha says. “Back then, we were using fused-deposition modeling (FDM) to make patterns and other tooling, but when we saw how we could completely circumvent the whole tooling process, a light bulb went on and I said, ‘This is where we need to be.’”
He’s talking about 3D sand printing, a binder-jet technology that selectively applies an alcohol binder to sand that’s been premixed with an acid catalyst. It’s not all that different than your inkjet printer at home, Lamoncha explains, except that the “paper” in this case measures about 990 mm wide x 1,780 mm long and 0.28 mm thick. As with most 3D printers, a print head traverses back and forth, repeating the deposition cycle over and over again until the part—in this case, a sand core or mold—is complete.
“Roughly half an hour later, the chemical reaction has finished and you can roll the build box out and start evacuating the unused sand from around the cores, a process called depowdering,” Lamoncha adds. “Between our 13 printers, we’re processing between three to five railcars a month, each carrying 80 tons of sand. We make a lot of cores.”
The machines Humtown uses to make these products come from ExOne, the company that introduced Lamoncha to the technology in 2014. Yet, as the entrepreneur quickly discovered, industrial-grade additive manufacturing (AM) is much more expensive than the FDM printers to which he and his team were accustomed. “Suddenly, we were contemplating a million dollars in investment for a technology that—back then, at least—had a very limited market.”
It was a tough stretch both financially and mentally. But thanks to some assistance from America Makes (part of the Dept. of Defense’s Manufacturing USA network), Lamoncha’s son Brandon—Humtown’s director of AM—soon found himself at the University of Northern Iowa (UNI), where he worked with Jerry Thiel, director of the school’s Metal Casting and Foundry 4.0 Centers, on test-printed cores for sales and marketing efforts that benefited UNI and Humtown alike. That soon led to another America Makes project, this one with an institution much closer to home
“The U.S. Air Force was working with Youngstown State University (YSU) here in Ohio on a program called maturation of advanced manufacturing for low-cost sustainment (MAMLS),” Lamoncha says. “They wanted to buy a sand printer, but had neither the expertise to operate it nor a place to house it. By that time, we had both.”
Having a machine onsite was a turning point. A second soon arrived, followed by a third; and, today, Humtown Products has a sister company—Humtown Additive—with a 100,000-sq-ft (9,300-sq-m) facility in nearby Youngstown to house its fleet of ExOne sand printers. More are sure to come.
While he can’t disclose customer names, Lamoncha did share some notable success stories. In one case, a company that spent several hundred thousand dollars with another manufacturer on tooling for a high-performance marine engine, soon discovered it was unable to achieve the desired tolerances. Humtown Additive now prints “cores by the thousands” for that customer.
A similar example comes from a racing company that wanted to make “a really trick LS-style V-8 cylinder head.” Unfortunately, the casting was too complex for traditional core-making processes. But thanks to AM, which provides greater manufacturing freedom and the ability to consolidate multiple cores into one, the customer was able to benefit from airflow and combustion characteristics in what has proved to be a winning design.
Another customer approached Humtown about making conventional “blown” cores for an airbrake component. When Lamoncha told them it would be a few dollars cheaper to print the cores, he was met with skepticism. “Knowing 3D printing’s reputation as a low-volume process, they asked me how we could possibly print 90,000 cores a year?” The answer, he says, was simple: “We’ll buy more printers.”
“The engineering community needs to know that there’s now a robust supply chain of 3D sand printers and manufacturers available to support foundries,” Lamoncha adds. “For anyone wishing to get their products to market more quickly and with less investment, or who want to develop products that can outperform the competition, now is the time to start doing that.”
It’s not the first time that Lamoncha has bucked the status quo. As a young pattern-maker working under his father’s watchful eye, he was the first to push for ways to modernize the ancient sand-casting process (see sidebar) and move beyond traditional pattern making.
His first step in this direction was to pursue what were at that time considered novel approaches to sand core and mold making, namely air-set and cold-box processes. Each utilizes a resin rather than clay binder. But where air-set components have the resin and catalyst already mixed with the sand and harden after being hand-packed into the tool, the cold-box method forces an amine gas through resin-bearing sand, curing it within seconds.
Regardless, both produce stable mold components and do so in far less time, making them ideal for high-volume applications like brake rotors and other automotive components. “We still use the cold-box process in our other facility and I don’t foresee that changing anytime soon, but 3D printing not only simplifies and expedites manufacturing, it produces molds and cores that would be far more difficult or even impossible with traditional methods,” he says. “It’s a very cool technology.”
Content sponsored by Humtown Products. For more information, visit www.humtown.com or call 330-482-5555.
Sand casting is an ancient art, one that dates back millennia. It begins by constructing a reverse image of the workpiece—the pattern—which is typically machined from metal, wood or plastic. Due to molten metal’s tendency to shrink after pouring, the pattern must be slightly, but precisely, oversized to compensate and have sufficient draft that it can be removed after mold making.
The flask is a metal box made of two halves: the cope and drag. The operator partially fills the latter of these with a special blend of sand and clay or other binding agent, then sets the pattern near the parting line and packs sand around it. For parts with undercuts, holes or internal cavities, a core or series of cores made of compacted sand are placed into the mold, where they are supported by several small metal spacers called chaplets. A series of gates and runners must also be created to allow hot metal to flow in and gases to escape.
The cope is then attached and the flask is filled to the top. After compacting the sand, the cope is gently separated from the drag, the pattern removed and the two halves reassembled. The mold now complete, molten metal such as iron, aluminum or steel is poured into the cavity—when cool, the flask is disassembled and the sand, including the cores, is broken away from the finished workpiece, screened for contaminants and reused.
Friendly Lenses
While appreciating the history lesson, Humtown CEO Mark Lamoncha also embraces next-generation technology. And he recognizes the importance of bringing younger workers into the manufacturing fold. This includes his son Brandon, who plays an integral role in the company as vice president; and, like his father, got his hands dirty at an early age.
“I was about thirteen years old when I started sweeping floors and helping out around the shop,” he says. “From there, I learned pattern-making and then became a CNC machinist through an apprenticeship.”
Humtown struggles with the skilled labor shortage just like any manufacturer these days, but has been proactive in solving this widespread problem. “Many people were told growing up to avoid manufacturing, which is why it’s critical that we educate young people and introduce them to the trades from an early age,” says the younger Lamoncha.
One way to do this is via plant tours. Students are brought in a couple at a time, where they learn the 3D sand-printing process, are shown how to build job boxes, and are encouraged to bring in friends and classmates. They can then give similar tours to their peers, thereby spreading the good word on manufacturing. For example, 6th graders Ryker and Makayla recently led their classmates through the facility, where they learned about the design process and then used a flash drive to upload files to the ExOne. They observed sand printing in action, depowdered parts and saw how to safely ship sand cores. Similar tours are offered for students in other grades.
“Rather than me or somebody else from our company calling kids and saying, ‘Hey, this is cool, you have to learn more about this technology,’ the message comes from someone their age. It means so much more to them, which is why we call the program ‘Through the Lens of My Friends.’ But we’re also involved with Youngstown and Cleveland State University and have had several students come to work for us as interns. It’s very important to Humtown and is critical to the industry overall, so we’re excited to keep doing that.”
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