Improved Hydraulics Manage Spring Force, Slash Cycle Time
|Sensormatic employs five of these Neff Model H40-3M 4-post hydraulic presses to blank styrene-coated metallic security tags, 144 at a time. Press bed size: 33 in. square, with 30 in. of daylight.|
“Also, the presses—120-ton C-frame models—were flexing enough under load that they would move out of tolerance,” adds Simone. “Our punch tolerances are tight—0.0002 in.—so this flexion of the press frames caused premature die wear.”
New Presses, Upgraded Hydraulic Circuitry
As a result of the presses’ inability to manage the stripping force during press retract and to improve press rigidity, Simone ordered five new 120-ton C-frame presses from Neff Press, Inc., St. Louis, MO, with beefed-up frames that, according to Simone, immediately solved the flexion issue. To replace the last of its aging hydraulic presses, Simone opted for five 4-post presses that allowed him to reduce press tonnage to just 40 tons.
At each of the two facilities manufacturing the security labels, Motoman six-axis material-handling robots load styrene-coated sheetmetal blanks, one robot serving each press. Underneath each blanking die feeds, left to right, a continuous roll of adhesive-backed liner, so that as the blanked labels fall from the sheet they adhere to the liner, which then rewinds at the opposite end of the press. The liner steps and repeats in registration with the press stroke, with a cycle time of 4.7 sec.“When we approached Neff Press to help us upgrade production, we asked for a 5-sec. cycle time,” recalls Simone, “quite a significant improvement
Sensormatic UltraMax anti-theft
labels comprise a metal-alloy tab coated with multiple layers of
styrene laminate. One stroke in a hydraulic press blanks 144 of the
labels out of a large s
from the 11-sec. cycle time we had been achieving. Eliminating the pad bounce, in addition to firming up the press structure, got us where we wanted to be, and beyond.”
Better Control = Less (Zero) Scrap
Eliminating pad bounce from the 16-ton stripping force was achieved thanks to a dramatic upgrade in hydraulic circuitry, says Simone. “The original presses used fixed-displacement pumps and solenoid-operated valves,” he says, which offered little process control. “The newer presses use variable-displacement pumps and proportional valves, which give us better control of all of the fluid in the presses.
The Neff 4-post presses are H40-30M models with beds 33 in. left to right, 33 in. front to back and with 30 in. of daylight. A cutout in the bottom bolster of each press allows the positioning of a vision system used to inspect the security labels in-process. The power unit—motor and pump assembly—mount externally and upside down to provide full access to all four sides of each press, allowing Sensormatic to easily integrate the coil-feed system that delivers the adhesive-backed liner, as well as the robot, vision system and scrap-removal system.
Each press runs with a 12-in. stroke, 2 in. of work in 2.9 sec. And a 30-hp power unit generates ram speeds as high as 1200 in./min. MF
See also: Neff Press, Inc.
Related Enterprise Zones: Presses
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