Page 30 - MetalForming August 2012

Servo-Drive Presses
We’re speed-limited based on the drives and motors available, as well as by the ability to securely grip the material as it feeds. That’s where the industry will see technology advances related to feed equipment—so we’re not the speed constraint.”
Speed constraint becomes most crit- ical when metalformers operate a servo press in pendulum mode. “In this oper- ating mode, completely unique to servo presses, we cannot only be concerned with acceleration and feed rate, and just play beat the press,” says Willie Chacko, CEO of feed supplier Dallas Industries. “In pendulum mode, there’s often precious little time available for us to fit in our motion profile to index the material before the next press stroke.
“With a conventional press, we run the feed in impulse mode,” Chacko continues. “The press control says feed and we feed. Then we signal when the feed is complete so that the press can stroke. Now we’ve learned and adapted
This screen capture from digital video footage of a servo-drive press in action, provided by Anchor Danly’s Ray Osborne, illustrates what can happen to ball-bearing cages when the ram accelerates rapidly from BDC and then reverses quickly from TDC. At this point in the stroke, the ram is rapidly accelerating downward just milliseconds after TDC. The cages have lost their timing and position, ultimately leading to performance problems and eventual damage to the retaining hardware.
the technology so we can synchronize our motion with that of the servo press, and still develop a smooth motion pro-
file in the time allotted.”
What Chacko is alluding to is Dallas’
ServoPressSelect feed control, slated
Drive Your Press with Innovation
Hydraulic Press Drive PSH
learn more about Voith
Servo Press Drive PSH sales-rut@voith.com
28 MetalForming/August 2012
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