Page 19 - MetalForming Magazine September 2022

“These newer specialty washers,” Childers explains, “primarily for automotive applications, often require design features such as ribs to help improve fastener reten- tion when installed. We’re even seeing requests for dual-cham- fer washers, and features such as coined channels to allow coolant flow through the wash- er. And, we have customers manufacturing hydraulic equipment looking to move away from machined washers to stamped.”
Searching for the Right Press
The key to opening the door to these new lower-volume higher-mix and complex jobs laid in the firm’s search for the right press to add to its lineup.
Art Metals invested in its new adjustable-stroke press and one- out flexible die to react to an industry trend toward manufac- ture of relatively low-volume production of specialty washers, primarily for automotive applications.
move to our coining presses to form the unique features that our customers specify.”
Coil-fed (from a Universal Feed coil line, formerly Feed Lease), the new press process- es aluminum grades as well as three grades of carbon steel, from strip 4 in. wide and nar- rower. Feed length is automat- ed through the part program on the press control. The die also is equipped with in-die sensors to detect part-out and double-sheets (a slug or if a portion of the tool fails).
“Honestly, it’s a slick tool design,” Wyan says, “that allows the press operator to not only change the tooling at the press, but should he need to take it out of the press to perform additional servicing,
“We needed the flexibility to run a wide range of part sizes, along with maintaining our commitment to our customers to provide tight tolerances on concentricity, a critical spec,” says Childers. “To hold those tolerances, we typically use compound blank dies. With these, the parts eject from the center of the tool, so that when the die opens each part is blown out in the middle.
“With this new press,” he continues, “we felt that an inclined model offered the best solution for part ejection and allowed us to run at a higher stroke rate than we could on our existing straight- side presses.”
Since installing the new press in October 2020, that’s exactly the improvement in productivity the firm has experienced.
“While we’ve mainly been using the press to run new low-volume work, in the neighborhood of 1 million pieces/yr., versus tens of millions for traditional higher-volume washer orders,” explains Wyan, “eventually we plan to move over some of our existing work, as those legacy high-volume dies require service and rebuild.”
Childers notes that the new press
has allowed the firm to capture a lot more sales, “as now we’re more cost- competitive on lower-volume jobs,” he says. “And, some customers have told us that they were having problems sourcing low-volume jobs, so we’ve seemingly addressed an industry-wide challenge. And, with new customers sourcing lower-volume jobs, they’re now coming to us with high-volume work as well, which is icing on the cake.”
One Slick Tool Design
From the die-design perspective, changing out a conventional multiple- part-out die can take as long as 90 min. on the firm’s conventional straightside presses, lost press time Wyan and his production team sought to avoid on the newer shorter-run jobs it sends to its new inclined press. That led the firm to develop a single-part-out tool for the press that allows it to swap out cer- tain die components and inserts as it adjusts the tool from one part number to another.
“We developed the tool design inhouse and had it built at a local die shop,” Wyan explains. “We can use the tool to stamp blanks for several dif- ferent part numbers, some of them specialty washers. The blanks then
it’s only four bolts on the bottom and four bolts on the top. And, it’s small enough so that one person can load it onto a die cart and work on it, enabling fast changeover.”
“We did consider a servo press,” Childers admits, “but the price was a concern. And, the inclined-press design was a need based on our history here with straightsides. The incline makes the press more user-friendly in terms of getting the parts out without ricocheting and potentially damaging the tooling.”
Speedy and Flexible
How much faster can the firm run legacy tools on the new press? “It maxes out at 200 strokes/min.,” Wyan says, “when we use the shortest stroke. Even on a one-out tool at 200 strokes/min., we can produce more than a two-out die running on a conventional press at 70 strokes/min.”
Stroke, set manually by the press operator following job-router instruc- tions, ranges from 12 to 110 mm.
“We try to run a family of similarly sized parts back-to-back to minimize die-insert changeovers,” Wyan explains. “We have parts that run at 12 mm, but not at the high end; 90 mm is about as much as we need right now, but we see
16 MetalForming/September 2022
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