Page 12 - MetalForming-Oct-2018-issue

Tech Update
Energy-Efficient Servo-Hydraulic Press
portions of the stroke. The press’ cushion cylinder also is operated by servo motors that work as gen- erators. Braking energy distributes to motors used for acceleration and form- ing through a kinetic storage system and a central direct-current converter. Because energy stores within the press, electricity from the grid during peak loads is not required, resulting in a lower connection fee. Stored energy surpluses also can be restored
AP&T has introduced a new servo-hydraulic press, which reportedly offers short cycle times, high precision, low energy con- sumption and minimum need for main-
tenance. The press features several
technical innovations. First and fore-
most, the hydraulic system’s control
valves have been replaced by servo
motors, which means that speed, position and press force are completely controlled electrically.
to the grid.
A closed-loop system monitors the entire press
“The design has made it possible to limit the
number of unique moving parts, cut down on oil
volume, reduce pressure in the hydraulic system
to a maximum of 250 bar, and eliminate the effects
of any variations in oil temperature,” says Patrik
Haglund, AP&T product manager-presses. “This
lays the foundation for a very robust process with
a high degree of availability and repeat accuracy, at the
same time that the need for maintenance is substantially reduced.”
process and continuously controls slide movements, quickly corrects any deviations, and ensures precise speed and position, according to company officials. Also, the system actively governs the slide’s par- allelism in relation to the press table—a unique
The servo-motor solution also reportedly has reduced energy consumption by 40 to 70 percent, depending on the application. Heat loss generated by pressure valves can be avoided, and some servo motors are used as generators during nonworking
“The acceleration and retardation speed is an impressive two to three times higher than that of a conventional hydraulic press, thus enabling extremely short cycle times,” Haglund says.
AP&T: www.aptgroup.com
Next-Gen. Servo-Press Control
analysis. An automatic counterbalance control with an electrically controlled pneu- matic regulator, another option, automat- ically sets the slide counterbalance pres- sure during die setup. With the automatic die-height-adjustment control option, a resolver tracks die-height position and reports it to a control module. A variable- frequency drive for the slide-adjust motor provides two adjustment speeds—high speed (for faster adjustment) and slow speed (for fine adjustment). And, slide position can be set automatically from the job-recipe memory.
Aida-America, Dayton, OH, has released the next generation of its exclusive Allen- Bradley-based DSF-series servo press control for machines with capacities from 315 to 3500 tons. The control utilizes an Allen-Bradley Compact Logix programmable logic controller for press operations, diag- nostics and safety on a 19-in. Allen-Bradley PC touchscreen. Features include direct access to a pdf of the press manual and infinitely programmable stroke and velocity profiles, reportedly allowing for higher productivity than mechanical presses and improved precision as compared to hydraulic presses.
display of actual and virtual crank angles. The control’s teach function minimizes the possibility of operator-entry error, while a three-speed, CNC handwheel step-feed control provides precise setup functionality.
Available options include an integrated four-channel, strain-gauge-type, forward- and-reverse tonnage monitor with signature
integrated function that contributes to high forming precision and less tooling wear.
The servo-press control system includes a Beckhoff servo-motor motion controller, a 500-job recipe with flash-drive loading/ unloading capability, remote diagnostics via eWon routers, 16 die-protection control channels with PNP/NPN inputs and sensors interfaced and stored in the job-recipe memory, 16 programmable-limit-switch circuits with sensors interfaced with the job-recipe memory for quick setup, and
The automatic single-stroke option solves timing issues when the automation equipment cannot keep up with the press. With this feature, the press automatically stops and waits for the next initiation signal from the automation equipment. Other options include continuous on- demand operation, servo-feed-control integration and servo-press/servo-transfer integration interface.
10 MetalForming/October 2018
www.metalformingmagazine.com
Aida-America: www.aida-global.com