Page 22 - MetalForming November 2019

Servos
Offer
Solution
for AHSS
Servomechanical presses provide solid options in combatting tough-metal challenges such as springback, reverse tonnage and more.
We’re well on our way to run- ning out of adjectives to describe the new steels invading our forming and fabricating operations: high-strength steel... advanced high-strength steel (AHSS)... ultra-high-strength steel. Before super- duper-strength steels hit the market, we’ve got to learn to tackle what we already have, and develop plans for what’s coming. That’s the focus of R&D throughout manufacturing, and a major theme of the EWI Forming Work- shop, co-sponsored with Precision Met- alforming Association and held in October at Ohio State University.
One presentation, Successful Form- ing of Aluminum and AHSS Using a Mechanical Servo Press, offered up ser- vomechanical-press solutions for form- ing ultra- and AHSS and combatting such hazards as springback and reverse
BY LOUIS A. KREN, SENIOR EDITOR
tonnage. Beginning with a general comparison of mechanical, hydraulic and servomechanical presses, Shrini Patil, product manager for Aida-Amer- ica, dug deeper into AHSS issues faced by stampers, and presented some shop-floor examples where servos shine.
More Energy at Lower Speed
Hydraulic presses provide capacities exceeding 50,000 tons, dwarfing those for mechanical (less than 6000 tons) and servo-driven (to 3500 tons) machines. As for speed and torque, hydraulic units maintain full torque throughout the stroke, with speed diminishing toward the top. On the other hand, traditional mechanical presses provide diminished speeds toward the bottom while maintaining torque on a standard torque curve.
While servomechanical presses hold to the standard torque curve, they exhibit speed versatility throughout the stroke, as we’ll find in upcoming examples. On the next set of features― repeatability, energy management, maintenance and operating cost― servo-driven presses win hands-down, according to Patil. The technology behind such capabilities translates to a high initial cost, but also the lowest lifecycle cost, he says, while providing attributes that aid in forming difficult materials.
Energy Ready When Needed
Let’s look more closely at one ser- vomechanical-press feature, energy
20 MetalForming/November 2019
www.metalformingmagazine.com