Page 38 - MetalForming February 2016

Precise Cylinder Control
Best Clamp in the Industry
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Panel Present Detection & Double Sheet Detection Clamp communicates when a panel or multiple panels are detected.
Series GRM Pneumatic Workholding Clamps
Fig. 4—A touch- screen operator interface connects via Ethernet to both a PLC and the motion controller for operator mes- saging, power-unit control, sequence control, and real- time monitoring of cylinder positions and forces.
to four proportion- al servo valves that operate the cylin- ders.
During the ini- tial steps of the cycle, the motion controller is set to control the posi- tion of the outer loop, ensuring that
the individual cylinders are level while monitoring and limiting the total force being applied. The final step seam- lessly transitions to force control, ensuring that the press applies the specified tonnage.
“We’ve now got absolute control of position and pressure, so we can run four cylinders simultaneously, or we can run two different press functions at the same time, and get a perfect part every time,” explains Moore.
Control Frees Operators, Yields Precise Press Operation
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The press system also contains a PLC for supervisory control. The motion controller connects to the PLC via Ethernet for PLC functions that include storing recipes, downloading motion instructions, monitoring motion results and monitoring the power unit. A touchscreen operator interface (Fig. 4) connects via Ethernet to both the PLC and the Delta RMC for operator messaging, power-unit con- trol, sequence control, and real-time monitoring of cylinder positions and forces.
“Synchronization is a big portion of our requirements,” says Moore. “With the motion controller controlling the position of the cylinders, both cylinders are kept within a couple thousandths of an inch of each other during press operation in order to maintain com- pletely flat platens.”
Missouri Metals’ older machines weren’t capable of maintaining this level of precision because the quality of production was heavily dependent on the machine operator.
“Requiring an operator to open a hydraulic valve,” Moore says, “can cause mistakes that result in wasted material. Now, we don’t scrap parts.”
In addition, the older presses limit- ed productivity by requiring an opera- tor to be at the press constantly during production. Now, the operator turns on the press, selects the program and pushes the “up” button. Then the oper- ator places the part, presses the “down” button and can move on to another machine to perform other tasks. MF
Workholding Solutions
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MetalForming/February 2016
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PHD’s Series GRM Clamps offer the BEST switch technology available in the sheet metal handling industry