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Picture This, May 2013 — Going with the grains
Going with the grains
The path to this place of intense heat and pressure is long. More than 26 centuries ago, the Chinese discovered they could pour molten metal into impressions in moist sand to make tools such as plows. In 1946, Frank Hamlin began using a similar technique — called sand-casting — in an Illinois plant. Much has changed, but the basics are the same. Aluminum still liquefies at 1,221 degrees Fahrenheit and that keeps the doors open at Hamlin Casting Corp. in Pilot Mountain. Over the years, CEO Bill Welden says, it has sand-cast more than 60 million pounds of parts for the marine, electrical, trucking, aerospace and other industries, the most of any such foundry in North America. “It’s faster and, costwise, the least expensive way to go. Also, in our case, customers are dealing with somebody that’s in the United States, so they can reduce the time it takes to deliver a product by at least a third.”
Hamlin Casting alloys technology, automation and craftsmanship. The process starts with a blueprint from a customer such as Phoenix-based U-Haul Corp., Sidney, N.Y.-based Amphenol Aerospace Co. or nearby Mount Airy-based Pike Electric Corp. The desired part might be something weighing a few ounces or a 50-pound lighting fixture. “From that, we’d make a prototype,” Welden says. Once it’s finished, a conveyor in the 61,000-square-foot factory carries moisturized olivine sand, which is strengthened by clay and resists expansion when heated, into chambers where 1,000 pounds per square inch of pressure forces it around the pattern. What remains after the pattern is removed is the sand mold.
Aluminum ingots are fed into furnaces powered by fuel oil — up to 30,000 gallons annually — where the metal melts and flows into holding tanks. Workers use ceramic ladles to pour it into molds. After hardening, parts go through shake-out machines to remove residual sand. Finally, pieces are cleaned, ground and milled to the customer’s specifications, and burrs are polished off. The company can make quantities up to about 5,000. “Anything above that usually is done by foundries with permanent molds, rather than sand-cast,” Welden says. Production isn’t limited by the durability of the sand mold as much as the company’s workforce of 10. No two orders are alike. “It’s all custom work. Each customer sets his own specifications.” It was a different kind of specification that brought Hamlin Casting to Pilot Mountain.
In 1982, Weldon and wife Susan, who is the founder’s daughter and Hamlin Casting president, joined the business in Illinois. They moved it to Pilot Mountain three years later. “We had a lot of customers in the South, and it seemed fit to be closer to them, to better serve their needs,” Welden says. There were personal factors, too. “We liked the small town, with the close-knit atmosphere. It looked like a great place to pursue a career and be a good fit for family life.” The future of Hamlin Casting looks much like its past. It has weathered recession — company officials don’t release revenue or profit — and has an advantage that can’t be moved overseas. Not even to China, where sand-casting began. “The most important thing we have is the quality of the castings we produce. But also, a customer can call us on a Monday and have parts by Friday, versus an offshore supplier when they might be months down the road.”
— Edward Martin