Page 18 - MetalForming November 2009

Robots Slide
and Glide
Three stamping-press-tending robots at metal-furniture manufacturer The HON Co. ride floor rails to move from press to press, serving up sheetmetal blanks to two-station transfer dies.
BY BRAD KUVIN, EDITOR
Each robot in the HON Co. pressroom tends two presses, one tooled for stamping legal-size drawer parts, the other for letter-size parts. Robots mount on a manually adjustable riser assembly that rides a floor-mounted track to access the two presses, with a hard stop and locking mechanism to secure the robot at each press.
Avigorous rapid-continuous-improvement (RCI) program directed
toward ongoing training and implementation of productivity-enhanc-
ing manufacturing projects has earned The HON Co. plant in Cedar-
town, GA, heaps of industry recognition. The list of awards goes on and
on for the plant and for its parent, HNI Corp., touted as the second-largest manu- facturer of office furniture in the world; HON makes panel systems, desks, storage files and tables. HNI has earned recognition as one of the 50 best manufacturing companies (IndustryWeek magazine), and it was named one of America’s Most Admired Companies in the furniture industry in 2008 by Fortune magazine. Indus- tryWeek named the HON plant in Cedartown one of the 10 best manufacturing facil- ities in North America in 2005; the plant won a Shingo Prize for Excellence in Man- ufacturing in 2007; and it earned Georgia Manufacturer of the Year in 2006 from the Georgia Department of Technical and Adult Education and the Georgia Depart- ment of Economic Development. And that’s just the beginning—other awards have come for the firm’s expertise and performance in design, pollution control and orga- nizational excellence.
RCI drives all of the innovative ideas that pour out of The HON Co.’s 600 employ- ees, as they strive to improve safety and quality, reduce costs and improve productivity.
Stamping-Press Productivity Project
The HON steel-fabrication department supplies four assembly lines in the plant, two of which manufacture vertical filing cabinets, one which makes metal desks, and a fourth line that assembles lateral files and storage cases, shelf files and bookcases. Early in 2000, an RCI project had a HON work team focused on improving the safety and productivity of its stamping-press operations within the steel-fabrication department. There, presses hem 0.022-in.-thick mild-steel blanks for drawer fronts, in two sizes to accommodate letter- or legal-size files. Hand feed- ing of blanks into two-station transfer dies at a production rate of 400/hr. taxed the firm’s press operators, who used gripper wands to move the blanks rather than reach into the dies. The process proved safer than hand feeding to be sure, but manipu- lating blank after blank on the end of the wands led to ergonomics issues—carpal tunnel syndrome to be exact.
“An RCI project to improve the three press lines that hem filing-cabinet draw- er-front blanks led us to investigate the use of robots to handle the blanks,” recalls HON maintenance engineer Burt Coffman. Noting his skepticism at the time, Coff- man says, “I didn’t think there was any that this would work. But the robots we’ve put on those lines are unreal. Productivity is fantastic, and they don’t take breaks.”
A 3P (production preparation process) project proved out the robotic press-tend-
ing cell arrangement and HON brought in local robot integrator TEC Automa- tion, Inc., Canton, GA, to manage the project. The first press robot went online late in 2000, a second in 2001, the third in 2003, and the plant will fire up its fourth press-tending robot before the end of 2009. Each robot tends two presses, one tooled for stamping legal- size drawer parts, the other for letter-size parts. Robots rides a track to access the two presses, with a hard stop and lock- ing mechanism to secure the robot at the press. Presses are 100- and 150-ton models with 8-in. stroke to accommo- date the robot end-of-arm tooling. Robots are ABB (one) and Nachi (three) six-axis pedestal-mounted units.
All in Six Seconds
“TEC designed the tool and includ- ed vacuum sensors to verify part pres- ence,” says Coffman. Each die compris- es two stations—bend and crimp —so the tool carries two grippers, one to load a fresh blank in station one and the second to move blanks from station one to station two and to deposit fin- ished parts onto a conveyor. All in 6 sec.
“We designed the cells to keep the end-of-arm tooling as simple as possi- ble,” says TEC vice president Jim Webb, “and worked closely with the tooling vendor to add automation-friendly
16 METALFORMING / NOVEMBER/DECEMBER 2009
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