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 VFDs. The 755 series VFDs were programmed to perform in a gearing mode. While in the gearing mode, the VFDs 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 VFDs provide an electronic gear lock (ratio) to the line shaft.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.
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 from 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.