Problem:

The flexographic printing press consists of multiple printing stations, each printing a single individual color. In order for the colors to register properly on the moving web of material the tension must be controlled as the material exits the Unwind Section and enters the Rewind Section.

Solution:

Controlling Tension in the Unwind Section:
The tension in the Unwind is controlled by Cleveland-Kidder Ultra Cartridge Style Transducers and the WebPro Controller. The tension must be controlled just enough to prevent slack and wrinkles in the material as it unwinds. The machine operator keys the desired tension into the WebPro and it compares the set point tension to the actual tension measured by the Ultra Cartridge Transducers. The WebPro then sends a command signal to increase or decrease torque to a CMC Drive System or Cleveland-Kidder EMAG Brake attached to the unwind roll.

Controlling Tension in the Rewind Section:
The Rewind solution is the same as for the Unwind except that an EMAG Clutch is used in place of a brake.

Result:

This is referred to as closed-loop control system. The actual tension to the set point tension is continuously monitored and corrections are made in real time. This ensures that tension is continuously maintained in the most accurate and precise manner possible. Cleveland Motion Controls has the products to provide the complete system solution.