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Joe Jancsurak Joe Jancsurak
Associate Editor

Stamper's Success Is To Die For

September 1, 2018

Equipment and process changes ensure quicker die changes, increased press uptime and more at Northern Stamping, Inc.

Hilma hydromechanical clamping nuts on Aida 330T press at Northern Stamping
The Hilma hydromechanical clamping nuts shown here on this Aida 330T press at Northern Stamping are manually placed on the clamping edge of the dies and easily tightened with a few turns of an Allen wrench. The dies are clamped by applying hydraulic pressure to the clamping nut's internal piston. This preloads the T-bolts, securing the die the press ram or bed, enabling safe and simple die changes.

Throughout its 30-yr. history as a Tier One automotive supplier, Cleveland, OH-based Northern Stamping, Inc. (NSI) has evolved, adding along the way new technologies such as automatic transfer presses and robotic welding, and always mindful of continuous improvement. Lately, ramped-up production demands from the likes of General Motors, for whom NSI stamps nearly 2.5 million tractor-hitch parts (11 parts per assembly), as well as Chrysler, Cosma Magna and others, has driven NSI to transform itself like never before.

Over the past few years at its newly expanded 140,000-sq.-ft. stamping facility (NSI also has a nearby 85,000-sq.-ft. welding facility), the company has made these changes:

  • Implemented a computerized maintenance-management system (CMMS) system from Woodbury, CT-based COGZ, to increase equipment uptime by tracking tasks for on-time completion and equipment histories.
  • Maximized use of white boards to keep employees informed on the status of press tooling. Tools numbered in green represent those ready to run in the press, while red signifies tools that need repairs.
  • Reorganized the warehouse to ensure efficient packing and flow of parts, allowing for more work by fewer employees—from 10 to four—and freeing employees for other tasks.

Such changes were pivotal in allowing the company to achieve a General Motors quality-audit score of 96 in June 2018. “In the past, our tooling and maintenance departments weren’t as organized as they needed to be. Now we have right processes in place to clearly indicate the location of tooling and the status of dies” says Duane Enderby, NSI tooling manager.

Enderby also is quick to credit Jeff Krajnak, director of operations; Eric King, plant manager; Todd Aberts, maintenance manager; Scott Sheffield, vice president; and NSI owner, Matthew Friedman for playing key roles in the overall NSI process-improvement efforts.

NSI's organized warehouse includes coded bins of finished production parts
NSI’s newly organized warehouse, a.k.a. the Supermarket, includes coded bins of certified, ready-to-ship finished production parts.

“It really is a team effort,” says Enderby.

Clamps Improve QDC

Another missing component of the past now in place to aid NSI’s transformation: quick-die-change equipment. NSI’s newer 1650-ton Aida servo press, now equipped with customized hydraulic clamping systems from Hilma USA, led to the inclusion of Hilma hollow-piston cylinders from Carr Lane Roemheld Mfg. Co., Fenton, MO, on nine NSI mechanical presses and one 330-ton Aida servo press.

“Steve Amell, Carr Lane’s regional sales manager, worked with us to put together the manifolds on the 1650-ton press,” says Nathan Gottlieb, NSI process engineer and project coordinator. “This included the tubing, gauges—the whole hydraulic system. Then he pretty much pulled out of his back pocket, another type of clamp, a hydromechanical clamping nut. It was like a hollow-piston cylinder with no tubes, because the pressure is internal. We were amazed at the possibilities these presented.”

Here is how these clamps work: The clamping nut, is placed in the U slot of the die then tightened with an Allen wrench. This applies pressure to an internal piston, preloading the T bolt and clamping the die, when pressurized, a pin extends indicating that it is safely clamped. It's that simple.

“With the old method for changing dies,” says Enderby, “an employee had to use a fair amount of elbow grease and sweat to tighten the bolts. With the hydro mechanical clamps you slip them in the U slot, give them a quick twist, then just a few turns with an Allen wrench until the internal pressures loads the bolt and the pin extends, achieving 11 tons of clamp force."

White board shows status of tools used to make parts in presses
White boards show the status of tools used to make parts in the presses. Tools numbered in green represent those ready to run in the press and red shows tools that need repairs.

While ergonomics and safety certainly are important elements, a cost-justification study by NSI shows the huge impact these simple, newly installed clamps will have on NSI’s bottom line.

“With a per-press-hr. operating cost of $125, whether or not the press is running, and an average conventional changeover taking 2 hr., that’s $250 per changeover,” Krajnak explains, adding that on average, NSI performs 60 die changeovers per week across the 10 presses equipped with the hollow-piston cylinders. “That’s $15,000 per week, and $780,000 per year.”

“With the hollow-piston cylinders, we shave 15 min. off of each changeover,” says Krajnak. “That 0.125/hr. reduction equals 15 hr./wk., which equals 780 hr./yr., and an annual cost savings of $97,500. This reduces our cost by 12.5 percent.”

With savings like that, and the additional work—Enderby says the company has doubled its stamped-parts production over the past year—you might expect to see a larger workforce, and you would be right. In fact, NSI has increased its workforce from 80 employees in 2015 to 230 in 2018.

NSI’s trajectory continues strong, with Enderby pointing to nearly 30 more jobs coming down the pike. With its processes and QDC equipment in place, it’s fair to say that the future looks very bright at NSI. MF

Industry-Related Terms: Bed, Die, Edge, Twist, Ram, Run, Transfer
View Glossary of Metalforming Terms


See also: ROEMHELD North America, Aida-America Corp.

Technologies: Pressroom Automation, Stamping Presses, Tooling


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