Page 38 - MetalForming-May-2018-issue

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MetalForming/May 2018
www.metalformingmagazine.com
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speeds is challenging, and costly from an energy standpoint. Merging the benefits of servo-mechanical presses with the flexibility of hydraulic presses present a solution to that challenge.
In fact, AP&T has developed a hot- stamping process to produce high- strength-aluminum parts in complex shapes that reportedly can reduce weight by more than 30 percent as compared to steel parts. This innova- tion arose in tandem with, and helped drive advancements in, servo- hydraulic-press technology, according to Haglund.
AP&T is testing a 600-ton servo- hydraulic press, which benefits from a couple major advancements necessary when forming complex shapes from unique and new materials, such as high-strength aluminum, at production speeds.
Individual Cylinder Control a Big Advantage
The biggest advancement—and advantage—in the company’s servo- hydraulic press is individual control of each cylinder via servo drives and hydraulics, according to Haglund. This allows parallelism between the press table and the slide even if more force is needed in one corner of the part or at different heights along the part. If needed, press force remains consis- tently high during the entire press cycle, he explains, and can be distributed with precision. This delivers efficient, energy-saving operation and less wear on tools and the press itself. In addi- tion, maintaining such control means not having to overbuild dies to com- pensate for unexpected force.
Redesigned hydraulics represent another advancement. With force and
This complex, high- strength-aluminum part provides one
example of the capabilities and appli-
cations promised through the recent development of
servo-hydraulic presses.
direction controlled via an electric motor, needed valves and other hydraulic components are reduced or eliminated, meaning significantly lower energy consumption, less noise and less maintenance. Haglund estimates a 30-percent reduction in maintenance time and costs as compared to a tra- ditional hydraulic press, along with a longer service life. The reduction in energy usage translates to less gener- ation of hot oil, which in turn requires less cooling components.
Given these advancements, Haglund describes how servo-hydraulic presses in general, and AP&T’s new press in particular, provide benefits on the shop floor.
“This technology unites the consis- tently high press force and flexibility offered by hydraulic presses with the energy efficiency and excellent speed- control possibilities offered by servo- mechanical presses,” he says, noting that a servo-hydraulic press can, depending on the working cycle, achieve significant energy savings as compared to a conventional hydraulic press. “On our system in particular, acceleration and deceleration forces reach 250-percent higher than those on a conventional hydraulic press (owing to servo motors driving down the cylinders and precisely controlling deceleration), which enables substan- tially increased production capacity.”
Technology Worth Exploring
Users should not expect servo- hydraulic presses to approach the high- est speeds of their servo-mechanical brethren, but they’ll certainly outper- form in hot- and cold-stamping appli- cations where hydraulic presses typi- cally would get the call, according to Haglund. MF
Servo-Hydraulic Presses