DALE, IND. — Router manufacturer Thermwood Corp. is developing an additive manufacturing machine that can make print large, carbon-graphite reinforced thermoplastic composite parts — by both “adding” and “subtracting” the material.
Thermwood, based in Dale, is integrating a purpose-built vertical extruder from American Kuhne Inc. of Ashaway, R.I.
The special integrated extruder deposits the thermoplastic composite material to quickly create a structure that is close to the final shape, a process known as “neat net shape.” Once the part cools and hardens, it is then machined to the final shape.
The technology allows the 3-D printing of large parts.
The new systems will be based on Thermwood's Model 77, a semi-enclosed, high-wall gantry machine, which the company makes in sizes up to 60 feet long. An optional second gantry allows both the “additive” and “subtractive” processes can be performed in the same machine.
The initial development machine, which is nearing completion, can make parts measuring up to 10 feet by 10 feet and five feet high. The vertical extruder from American Kuhne can process more than 100 pounds of material per hour on the vertical 20HP extruder with 1.75-inch diameter and a 24:1 length to diameter ratio.
The extrusion system and heat are mounted on the machine, and move with the machine, allowing a high rate of feed and high acceleration rates, according to the companies.
“Thermwood's system will feature a full six-axis articulated additive deposition head, allowing it to build layered structures on both a horizontal plane as well as planes canted in any direction up to 90 degrees from horizontal,” Thermwood Chairman and CEO Ken Susnjara said.
The company's main products are computer numerically controlled routers that do complex cutting, for a variety of applications such as large plastic parts, aerospace, defense and woodworking.
American Kuhne is part of Graham Group in York, Pa., which also owns Graham Engineering Corp. and Welex.
“3-D printing is rapidly evolving and presents unique challenges, particularly at industrial sizes,” said Bill Kramer, American Kuhne's chief technology officer of extrusion systems.
Interest is growing in pushing the boundaries of additive manufacturing to make very large, structural strong, parts. Cincinnati Inc. of Harrison, Ohio, has adapted its large laser-cutting machines into a 3-D printer. That technology grabbed headlines for turning out 3-D printed cars at the North American International Auto Show and the IMTS show.
