Load cells. They're a common component in most tension-control setups on converting lines. Yet their performance varies, and if they don't perform correctly, they can be a source of much frustration, not to mention downtime.

For John Meyer of Shurtape Technologies, Inc., Hickory, NC, a collection of older LVDT-style load cells were causing problems on his pressure-sensitive tape coating lines. "They very easily became mechanically overstressed during web breaks, to the extent that we would have to shut down a line and wait for them to unstress, for up to an hour," says Meyer, Shurtape's director of corporate projects, engineering management. Shurtape Technologies operates multiple plants in the Hickory area, specializing in masking, carton-sealing and paper tapes, but also coating various foils and plastics as well.

Finally, in 1998, Shurtape managers took some advice from Italian coating-machinery supplier Rotomec and retrofitted some load cells supplied by FMS USA, Inc., Arlington Hts., IL. "They're mechanically impossible to overstress," says Meyer. "Within six months, we had retrofitted a handful here and there. We accomplished our first full-line load-cell retrofit in December of 1998." Since then Shurtape personnel, lead by engineering services group leader Ron Griffin, have retrofitted six coating lines, consisting of 5–10 tension zones apiece.

"The biggest upfront benefit to the FMS load cells was the elimination of the downtime we were experiencing," says Meyer. "However, the intuitive setup and maintenance, and the resistance to vibration and durability are also beneficial. These things seem to last forever."

For Griffin, the typical one-hour load-cell retrofits are eased considerably by the stainless-steel construction and design of the FMS units. "No hole drilling is involved, because they're supplied with 12 predrilled mounting holes to choose from," he says. "A changeout basically consists of removing the old load cell, turning the shafts down, installing new mounting brackets, and positioning the sensor at the correct angle."

Griffin says the maintenance staff immediately noticed the difference when the switch to the new load cells was made. "They weren't having to constantly fool with them," he says. "My phone stopped ringing as often. I'd say going with the FMS load cells was among the Top 5 things we've done in this plant."

By the time a new $6.5 million Rotomec coater/laminator was installed in 2001, FMS load cells had become the official Shurtape engineering standard. "This new line is designed to have a lot of flexibility," says Meyer. "It can run everything from foils to paper and plastics. Reliable tension control will be important in realizing the potential of this line."

"Over the years we've evolved with FMS load cells—from carbon steel to now stainless steel, and basically every model number of web-handling product they carry," Meyer concludes. "They've been valuable partners."