Page 24 - MetalForming January 2011

Press Brakes of a
Different Color
Traditional, hydraulic press brakes use gear pumps to pressurize lines that deliver oil to pistons. While the pumps prove fairly reliable, they have some disadvantages. For starters, they continuously draw power even when the press brake sits idle. They also are noisy and can cause machine vibration.
Worst of all: During production, temperature changes to the hydraulic oil can cause perceptible shifts in the ram, interfering with the ability to meet tight production specifications.
To eliminate the gear pump and other troublesome elements of traditional press brakes, manufacturers have devel- oped electric and hybrid press brakes.
Casey Schlachter is national press brake sales manager, Mitsubishi Laser/MC Machinery Systems Inc., Wood Dale, IL: 630/860-4210; www.mitsubishi-world.com.
Next-generation hybrid and electric press brakes are lean, green production machines that provide clean, quiet and accurate operation, while lending support to a shop’s bottom line.
BY CASEY SCHLACHTER
Hybrids employ hydraulic and electric technologies—hydraulic power still moves the ram, but a hybrid pump only is energized for a fraction of the day, and delivers exact positioning that does not rely on valve operation for control. This design also avoids the problems caused by changes in oil temperature.
How Green Press Brakes Work
The most common hybrid press brakes work with a motor that features a sealed shaft that reaches into a hydraulic tank. The shaft is attached to
and has direct control over a piston pump, which delivers hydraulic pres- sure to move the ram—but only when the operator steps on the foot pedal.
With electric press-brake technolo- gy, electric motors directly control ram movement with help from belts or gear mechanisms that drive heavy-duty ballscrews. Belt-driven ballscrew designs incorporate timing belts that encircle the motor’s pinion gear and another gear that sits directly above the screw. The ballscrew turns in and out of a nut attached to the ram, or
Electric press brakes prove reliable and efficient, and accurate—down to 1 micron.
22 MetalForming/January 2011
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