- May 01, 2007, Edited by Claudia Hine Managing Editor
There's significance behind the phrase “critical edge” at Smith & McLaurin. The company's specialty is labels for retailers in Europe, Australia, and New Zealand. All have precise specifications for the distance from the edge to the peel-off label on each roll, which is produced by strip coating or dry lap coating.
“Some customers want five millimeters between the edge and the label, while others want eight or ten,” says Graham McKay, quality systems manager. “That's our critical edge. When retail customers change prices, they need to peel off and apply new labels. We have to apply the adhesives in the right places and be in registration so it's easy for workers to lift off the label.”
To ensure the critical edge, the company purchased an LOL-5 stroboscopic inspection light from Unilux. The handheld, battery-powered LOL-5 is used in making a specialty product in which alternating uncoated and adhesive-coated strips are applied. The accuracy of the strip or dry lap pattern requires the ability to maintain tight width tolerances and control drift. Operators use the LOL-5 to inspect the product during coating to ensure there are no visual defects or sideways wander of the strip or dry lap pattern.
“More important, the LOL-5 also helps us inspect the product during slitting and rewinding,” McKay says. “Here, the inspection lamp is used to back-light the running web. The stroboscopic light enables operators to ‘freeze’ the image to differentiate between the uncoated and adhesive-coated strips to confirm that critical dimensions are being maintained.”
Yield Has Improved
“The adhesive is clear, but there are shades of white operators can see with the LOL-5,” McKay says. “We have been able to identify coating defects and monitor our quality better. We used to rely on the naked eye when the slitter was running in conjunction with a measurement at the end of each cut to monitor quality. We've improved our yield by 3 percent because we can inspect on the run to make sure we're maintaining tolerance.”
This year the company purchased another LOL-5 to be mounted on the transverse side of the web. This enables operators to monitor the back end of the coating operation and the slitter with a single light while remaining outside the safety beam.
“We've been very happy with our Unilux light, and now we'll be able to maintain the same function in a safer environment,” McKay says.
Smith & McLaurin Ltd.
Cartside Mill, Kilbarchan, Renfewshire PA10 2AF UK; +44 (0) 1505 707700; www.smcl.co.uk
Unilux — PFFC-ASAP 301.