Hydraulics Support Big Move to Bigger Parts

The brothers Hatch, Raymond, Walter, and Joseph, founded Hatch Stamping in 1952, and from the start the company concentrated on producing small stampings on smaller-tonnage mechanical presses. More than a half century later, Hatch Stamping and its 1000-plus employees stretch across 13 locations in Michigan, Tennessee, Mexico and China. As the footprint has spread, so has the company’s offerings.

Evolved to Larger Parts and Tougher Material

“Initally we were a stamper of small- to medium-sized parts, but in the past 10 years we’ve evolved into supplying larger, more complex parts,” says Stewart Claucherty, Hatch Stamping’s director of industrial engineering. “We started out producing clips and clamps on presses from 75 to 100 tons. In the last six years, we have purchased eight new mechanical presses, all with capacities to 1000 tons.”

Hatch Stamping continues to make smaller parts using its stable of smaller presses to support its larger value-added assembly work. Where only less than 20 years ago Hatch Stamping worked nearly exclusively with mild and cold-rolled steels, today, 80 percent is higher-strength steel, including dual-phase steels, driven by the company’s automotive customers.

Hydraulic Presses: Unchartered Waters

Driven by customer demand and growth, the combination of larger parts and higher-strength material led to another change at Hatch: the introduction of hydraulic presses. The company decided to make the investment three years ago, followed by a year of custom design and construction, including a three-month install and ramp-up.

Specifically, Hatch Stamping has added a four-press hydraulic line featuring a lead 600-ton unit backed by three 1200-ton machines, all customized and supplied by Macrodyne, Concord, Ontario, Canada. The line is dedicated to four sets of parts for one of the largest global, luxury automotive manufacturers—automotive roof-housing assemblies—and is fed blanks by a mechanical press in another area of the 100,000-sq.-ft. manufacturing operation at the headquarters location in Chelsea, MI. Kawasaki pick-and-place robots tend the line, where the lead press performs draw forming on a blank, followed by trimming in the second press and a qualifying restrike in the third. The last press performs hole piercing and, if needed, separation of the stamping into left- and right-hand parts. Staging stations between the presses hold parts awaiting completion of operations on successive presses, and a Prab system conveys scrap from the press bed underground and back up into scrap bins adjacent to the line. A central lubrication system (from Pax Products) keeps the parts well-oiled throughout their line journey.

“The Cpks are exceptional in that there is minimal variation across these parts as all of the piercing is done at the final press after a restrike operation to make sure a part is within tolerance,” explains Claucherty.

Macrodyne worked with Hatch counterparts to design the presses around the roof-system products. As a result, the dies, none longer than 100 in. or weighing more than 30,000 lb., fit snugly into the beds.

“We dedicated this line to a particular product niche, and know that the line is the perfect size for automotive roof systems,” Claucherty says.

Why go hydraulic?

“When we started looking at these new roof-system product lines, we needed to be able to manage the stroke speed, ram and slide velocity to deal with the yield strength of these steels and the required flow of material,” explains Claucherty, pointing out that the line runs high-strength low-alloy steel with a yield strength of 380 MPa in thicknesses between 1.2 and 3 mm. “Hydraulic presses provide that ability. For what we need to do, a hydraulic-press line was more economical than if we selected servo-driven mechanical presses, and provides the control we just couldn’t get with all-mechanical. And, this line, given the versatility of hydraulic drives, enables us to run other products if needed.”

Automation, Kaizen Events Spur Speed Uptick

From the start, improvements and overall equipment effectiveness led Hatch Stamping to open up additional capacity for future work. In addition, the company performed all robotic install and integration for its press line.

“These presses have a quick-fill feature to enable rapid lift and descent, then we can control speed and dwell time in the work portion of the stroke,” Claucherty says, addressing speed issues sometimes cited in the hydraulic vs. mechanical debate. “This allows us to run at speeds that approach those of a transfer line. And, with job recall through the human-machine interface, all line components can be quickly set up for each run.”

For a company with a history of speedy production and rapid-fire mechanical-press hits, the addition of a hydraulic line for this part mix represents a cultural change.

“We are a stamper and we run things quickly,” says Claucherty, “so it was a bit of a challenge to run slightly slower and move methodically. But we’ve gained efficiencies on the line via automation, such as the robotic press-tending.”

Die changes occur roughly once per shift, according to Claucherty, and swapping robotic fingers represents the most challenging aspect of each die

“We change out 10 robots with multiple fingers,” Claucherty says. “We have three people running the line, so one changes the fingers, one moves the dies and the third stages material and performs other duties. We are running four sets of parts through that press line across essentially only one shift, which is amazing when considering that hydraulic presses run slower than mechanical presses. With the automation, we keep that line humming.” MF