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Pulling Value-Added Operations into Hydraulic Presses

September 25, 2023
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…makes these shop-floor workhorses even more valuable, but doing so should be a deliberate, well-thought-out process.

The well-documented advantages of hydraulic presses—achieving full tonnage throughout the stroke and independently varying speed during the stroke—make them ideal options for incorporating added value, from performing secondary operations on the bed to implementing inline quality control and more. To help metal formers in their quests to add value when using hydraulic presses, we spoke with Mike Josefiak, design engineer for Greenerd Press & Machine Co.

Bring Quality Control into the Bed

Hydraulic-press-Greenerd-cell-value-added“Existing secondary operations on a stamping facility’s shop floor can be integrated into larger hydraulic press lines,” says Josefiak. “Quality control comes to mind as a good example. To ascertain material thickness, many shops will spot check material a few times per shift. This capability easily can be integrated into a hydraulic press cell, employing laser measurement of material entering the press to verify its thickness within a few thousandths of an inch, and comparing that to formed material thickness exiting the line.

“The press itself,” he continues, “provides feedback to the operator with each cycle as well as through a trend chart providing continuous raw data. Here, operators with minimal training might notice a trend—be it thickness, temperature or other process measurements—that tracks data traveling out of limits, then can notify someone to modify the process to keep cycles operating within optimum ranges. Controls provide obvious feedback to operators. Even relatively smaller press shops can employ this technology to streamline the stamping process. It sure beats not finding out until after three shifts that an operation has been running out of tolerance.”

Such in-process monitoring offers huge advantages.

“Even a process that runs well all month might then experience one shift with an excessively high scrap rate,” says Josefiak. “That one event can easily pay for inspection equipment needed for inline quality control.”

Data Provide Clues

A metal stamper should consult with its press provider upfront, with the provider understanding the firm’s KPIs and the information that really matters, to arrive at a correct controls solution for monitoring and adjustment.

“In some cases, we’ve talked with three or four press operators at a company, asking them what issues they’ve experienced,” Josefiak offers, “and what we as a press manufacturer can do on the controls side to prevent those issues going forward.”

Such insight can give a press manufacturer ideas as to future integrations and information on press and control capabilities that can be utilized to a greater extent. Sometimes, data gathering pays dividends in unexpected ways. To wit, Josefiak relays a recently investigated issue.

“During press commissioning, we see live data and it sometimes leads to incorporating data subsets,” he says. “A good example involves a manufacturer using humidity-sensitive material and having never tracked humidity. An operator mentioned difficulty running a successful process during a particular month. This manufacturer ran the process in a non-air-conditioned environment in a region with high humidity. With a small investment, we can outfit any press to track humidity along with other data. When reviewing the data six months later, the manufacturer found that, as humidity rose, so did scrap rates. Fixing the humidity problem via climate control would be an avenue to fix the scrap-rate problem.”

Standardize Part-Family Tooling

Another tip to efficiently add value in press operations: standardize the tooling.

“Metal formers should plan ahead for the part families that they run,” offers Josefiak. “As a press manufacturer, we can recommend a common die base with a common floor that allows everything on the line to work from common pass-line heights. Thinking this way brings more opportunities down the road.

“And,” he continues, “metal formers may run processes with parts batched into bins that then transport to a different area where the bins sit for two days prior to performing a secondary process. By planning ahead, they can give a hydraulic press the ability to hand the parts to a conveyance system for more-effective transfer. It’s simple to add technology that allows both buffering and immediate feeding to the next process.”

This ability to keep control over the product through multiple processes enables the relatively simple addition of value-added processes and maximizes a metal former’s investment in presses and other line automation.

Beware of Over-Consolidation

Adding value to hydraulic press operations no doubt can pay big dividends, but metal formers occasionally must pump the brakes.

“In reality, hydraulic presses function as platforms—large steel structures that accept material and offer opportunities to do plenty with the material within that space,” Josefiak says. “Some press lines house complicated die sets that perform seven, eight or nine actions. Such very complicated die sets can prove difficult to maintain, and uptime may suffer. One option: break those actions into multiple hydraulic presses, which can result in more consistent operation and greater uptime. It’s much easier to repair a single point of failure on five identical presses with all of the necessary spare parts available than to repair a complex die with several unique, custom-designed components. When considering adding value to a process, metal formers also must be mindful of not increasing the risk of downtime.”

Metal formers should be cognizant of the above when planning consolidation of processes to reduce needed floorspace.
“Metal formers will ask me how many square feet of space they can save by compacting as much as possible into a single hydraulic press,” Josefiak says. “It’s a cautionary tale—adding actions that truly add value and capture reasonable chunks of a process within a press can be beneficial, but don’t consolidate just for consolidation’s sake because it can go too far, and needlessly complicate operations.” MF

Industry-Related Terms: Bed, Die, Hydraulic Press, LASER, Lines, Point, Run, Scrap, Stroke, Thickness, Transfer
View Glossary of Metalforming Terms

 

See also: Greenerd Press & Machine Co.

Technologies: Pressroom Automation, Stamping Presses

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