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New Turret-Press Tools Deliver a Benefit Bonanza

Sunday, May 01, 2011
 

 
Red Dot manufactures rugged HVAC systems fabricated from 11- to 26-gauge galvannealed and HRP&O steel. Shown is a roof-top unit fabricated from 12-gauge steel.
Punch-press tooling gets a real workout when punching 298,000 lb. of sheetmetal per month. That’s Red Dot Corp.’s (Seattle, WA) average monthly throughput of punched components used in its broad line of heating, ventilation and air-conditioning systems installed in heavy-duty commercial and military vehicles.

With this volume of punched components, tooling life and costs contribute mightily to the bottom line. A focus on tool usage can reveal a wealth of possible efficiencies and savings by making changes, according to the tooling experts at Mate Precision Tooling, Anoka, MN.

With Mate’s help, Red Dot recently reviewed its punch-press tool usage, resulting in changes that significantly extended tool life and reduced tool-replacement costs. While reducing setup time also resulted, lights-out seven-day operation of Red Dot’s turret-press department became a reality, with substantial labor savings.

Punching Performance Picks Up

Red Dot Corp. employs 400 people to manufacture HVAC systems for the heavy-vehicle industry, on- and off-high. The firm operates three Finn Power machines: C5 Compact Express and F5 hydraulic turret punch presses, and an L6 laser-cutting machine. It processes galvannealed and hot-rolled pickled-and-oiled steel sheet from 26 to 11 gauge. Part runs range from just a few components, punched in minutes, to long runs of hundreds of parts taking 7 hr. or more.

“Like all companies, we’re on a tight budget,” reports Eric Cates, Red Dot’s laser and turret cell leader. “We strive to improve productivity from our manufacturing processes, and one of the areas we regularly analyze is punch-press tool usage.”

The C5 boasts a 20-station turret expandable to 100 tool stations using Mate Multi Tools. It can punch maximum hole diameters of 3.5 in. with accuracy of ±0.005 in., at press speeds to 1000 strokes/min; Red Dot typically runs its presses at 600 strokes/min. Important to the firm’s lights-out planning: the C5 features load-unload material-handling automation. Combined with careful tool and die clearance selection, the full 24/7 lights-out potential makes planning and scheduling Red Dot’s heavy fabricating workload optimally efficient and productive.

Maintenance-Free for 1.8 Million Hits

Edge quality and part flatness characterize parts punched on Red Dot’s turret presses, thanks to investing in new press tooling. New additions include a 1 by 0.250-in. trapezoid parting tool that made 1.8 million maintenance-free hits, and a 3 by 0.250-in. rectangular slitting tool mounted in
a fully guided holder

Cates, along with Gary Wilson, Red Dot’s manufacturing production manager, and Todd Schwartz, sheetmetal supervisor, challenged Mate to see what its tooling could do for them. Testing began with Mate’s Ultra 1 by 0.250-in. trapezoid parting tool in the C5 turret press.

 

“We set up the tool with a 0.006-in. die clearance on all gauges except 14 and 16 gauge,” says Cates, “which called for a 0.012-in. die clearance. We compared the punching performance with the previous brand of parting tool being used.”

Cates reports that the new tooling and the change in die clearance paid immediate dividends in improved edge quality for the parted sheets. And, the tool itself operated maintenance-free for 1.8 million hits.

“We were experiencing only 10,000 to 20,000 hits with our previous tool,” adds Cates. “And, the improved tool performance led to several other changes that dramatically improved our punching operations. For example, Mate recommended a second tool change—a 3 by 0.250-in. rectangular slitting tool in an Ultra Tec fully guided holder. In addition to improved tool life, the change improved part quality and sheet utilization, while boosting productivity from the turret press.”

Red Dot also switched a laser-processed component over to the turret press, by tooling up with a 0.024-in. die clearance for punching 12-gauge mild steel. This change improved processing time by 50 percent.

Rigidity Required for Punching Galvanized and HRPP&O Steel

By itself, the tighter clearance between punch and stripper is not enough to achieve high performance results. The key is the entire tool system of guide, punch and stripper—all must align with tight tolerances to remain rigid and stable under Red Dot’s daily high-volume punching conditions. The robust Ultra fully guided design prevents side-loading and twisting forces from developing, which can cause premature tool-edge cracks, dulling, galling and general wear.

The Red Dot team also appreciates the slug-free die design of the tooling. Previously, slug buildup posed a problem during Red Dot’s long runs, preventing lights-out operation. The slug-free dies are designed with a slight hourglass shape, with a 1⁄4 deg. taper entering and a 5-deg. taper exiting the die. When punching, the die’s design prevents the slug from pulling back out of the die. Once the slug is squeezed through the pressure point, it is free to fall a from the punching zone where it won’t cause problems.

The team credits the new tools with alleviating that problem, giving them the confidence to reschedule turret-press operations for lights-out operation following each day shift. The change also enabled Red Dot to operate its turret presses seven days per week with reduced operator attention and without compromising part quality.

“Since reviewing and upgrading our tooling, tool life overall has increased by at least 50 percent,” says Wilson, “and turret-press productivity has increased 10 to 20 percent. Press run-time savings averages between 1 to 2 hr. per 8-hr. shift. We’ve retrained operators on the fundamentals of tool handling—when to wear heavy rubber gloves, how to protect tools from damage and making tool setups faster and easier.

“We’ve also improved tool storage and inventory,” continues Wilson. “More tooling improvements are ahead.” MF

Article contributed by Mate Precision Tooling, Anoka, MN: 800/328-4492; www.mate.com.

 

See also: Mate Precision Tooling

Related Enterprise Zones: Fabrication, Tool & Die


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