With the introduction of new Avon Color IV mascara products, Avon Products Inc. (Morton Grove, Ill.) decided to upgrade its automated mascara package capping equipment to achieve higher and more consistent torque applied to the mascara bottle cap.

The filling line needed on-line torque measurement/application equipment capable of ensuring all caps were applied with 7.5 lb-in. torque to reduce the possibility of product dry out or leakage. The solution also needed to ensure that each cap was properly tightened, and if a cap was not tight, the bottle had to be marked as a reject and pulled from the system prior to packaging. Additionally, the solution had to minimize line downtime during installation and debugging.

Upgrade of the capping unit's controls involved installing a new servomotor, drive, and capping unit controller, connected to the existing programmable logic controller (PLC). Retrofitting the controls retained as much of the existing applications possible. Automation Horizons Inc. (Des Plaines, Ill.) was chosen to engineer and perform the equipment upgrade for the new mascara line.

To minimize installation downtime, a test/simulation station was built in the lab to develop, test and optimize the concept prior to installation. As this research and development effort evolved, an unforeseen obstacle was discovered. The engineering team realized that there was a need to control the speed and the applied torque simultaneously and independently. The drive as originally envisioned was unable to support those requirements from one programmed location. The decision to perform the original development on an off-line test/simulation unit allowed engineering to perfect the new capping unit without risking production downtime.

The drive hardware selected had three modes of operation: position, torque, and velocity. The drive and the PLC could control velocity and the torque, but not independently through any one device.

To control both parameters independently, Automation Horizons' system integrators added an analog card to control the applied torque, allowing the unit's motion card and drive to control speed and issue all drive alarms and faults. Velocity and applied torque are controlled through the operator station. The PLC then interprets the request, and controls the motor to yield the required speed and requested capping torque. Control of speed and applied torque is independent.

After initial testing, it was discovered that, by examining certain servo performance characteristics, mechanical maintenance issues could be predicted. The unit's operator interface was used to alert operators to problems before mechanical malfunctions due to mis-adjustment or wear could impact production.

After testing the lab unit, the new system was installed, tested, and validated on the line during a scheduled downtime, thereby minimizing impact on product scheduling and production.

For more information on Automation Horizons, visit www.controleng.com Comments? E-mail djohnson@cahners.com

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