Chill Roll Stand Modifications
Customer: A local printing company in La Crosse WI wanted to make modifications to a
used press in order to increase production.
Project Scope: To meet product margins, this company needed to increase the production speed of their
web printing line while maintaining product quality. To meet this goal, custom-built chill
roll stands were required to cool the web for further processing. The existing mechanical
drive link to the chill roll stands had to be removed, and in their place, electric motors with
electronic gearing were used.
Industrial Automation was contracted to design, construct, and install additional controls
that would operate the new chill roll stands. Both manual and automatic controls would
be needed for successful automation.
Project Design: Industrial Automation’s chill roll stand control design utilized Allen Bradley Powerflex
755 series VFD’s. The 755 series VFD’s were programmed to perform in a gearing
mode. While in the gearing mode, the VFD’s follow an encoder signal from a press line
shaft encoder. They also utilize an encoder signal from the output shaft of the motors they
control. By comparing the two encoder signals, the VFD’s provide an electronic gear
lock (ratio) to the line shaft.
Once gearing is accomplished, certain algorithms are added to the equation to modify the
speed control slightly, which in turn provides adequate tension for the web. This insures
print quality and cut-off accuracy.
Project Results: The completed control system allowed this company to increase production rates
approximately 450 units per minute to over 800 units per minute. Cut-off accuracy
was increased and overall yield is up as less material is scrapped when change
overs are required.