When you make tape, the adhesives have to stick—or your profits won't. And if the release coatings don't work properly, the profits get all gummed up as well.

Those are the constant concerns for Shurtape Technologies, the Hickory, NC-based converter of tapes used worldwide. Shurtape's products run the gamut from lint removers that pick up dust and pet hairs from dark clothing to high-tech applications in the automotive, computer, military and aerospace industries.

ISO 9002 certified, Shurtape has invested heavily in new technology and equipment over the past several years to produce its various tapes at five North Carolina plants. At Plant 36 in Hickory, a former textile mill, rolls of 5,000 to 15,000 linear yards are processed on a new automated printing, coating, laminating and curing machine that can handle webs up to 64 in. wide. Some of the more critical, value-added finishing operations take place here, as materials are run through the custom-designed unit. The only built-in inspection capability on the multifunctional machine is a gamma gauge to measure coating thickness.

When the facility opened in November 2000, as part of a 200,000-sq-ft, corporate-wide expansion, Shurtape considered making a printed tape that would be used for lint removal. The product would be private-labeled for a number of customers, and it could be produced most efficiently by coating everybody's material at one time and changing printing plates to identify each customer's product.

Shurtape managers recognized the need for an enhanced inspection system that could accommodate this production need, and maximize yield on its automated, value-added equipment. When plant managers and engineers saw Unilux Inc. (Saddle Brook, NJ) inspection systems at Pack Expo 2000 in Chicago, the light went on. They purchased two Unilux HD-851 stroboscopic surface-inspection lights that are expected to save $50,000 or more annually. The savings will come in reduced material costs as well as reductions in the value-added processing that took place when production errors went undetected. The company will also avoid labor costs associated with running additional product to fill orders.

"We coat many products in the plant and have a lot of different configurations," says Eric Patterson, process engineer for the plant. "The prep work is done in the Raw Department in our sister plant across the railroad tracks. Depending on the final product, they'll apply coatings for water shedding or release coatings. Then, the rolls come here, and we apply adhesives on one or both sides and sometimes add printing, just like potato-chip bags in a typical flexo operation."

After coatings and printing are applied, the rolls go through a lamination process before curing in a series of ovens built into Shurtape's proprietary coater/laminator. When adhesives or release coatings don't apply properly, defects show up as "chevrons," little chevron-shaped adhesive voids that will prevent a tape from sticking to a surface as specified.

"The Unilux system has paid for itself just on the chevrons," Patterson says. "They can be particularly difficult to see because there is some adhesive—just not the full coating. It's enough of a problem that the tape won't stick, and if the tape won't stick, the customer won't take it."

At the machine's full production machine speed, some 5,000 yards can be processed before the materials hit the inspection station. The web can be processed in up to 14 separate zones, and when machine operators find a chevron, they can make adjustments to each column.

With its square reflector for uniform illumination, each Unilux light provides 5,000 lux at 950 mm with 4 joules and 20-microsecond flash duration. The flash rate can be adjusted from 30 to 6,000 flashes/meter, and the intensity can be adjusted from 30 to 100 percent. This enables operators to match the light's performance to both the product and their own comfort levels, making inspection more effective and less fatiguing.

For items such as the lint-removal tape, where printing is also applied, the Unilux system lets the operator verify that the printing has been changed at the proper places to reflect the names of the companies under whose names the product will be sold.

"That's the real test of our inspection system," Patterson says. "We have to look for the chevrons across 14 zones, verify registration and make sure the right copy shows up in the right place without defects. We can get the Unilux light to literally 'stop' the web, visually speaking, to look at a 4-sq-in. print area. We also have to make sure that all the edges are straight in each column so that the tape will go through the slitting and packaging processes."

Shurtape has three slitters. Enclosed to muffle sound, each machine can slit 64-in.-wide tape webs into rolls of varying sizes, such as an 18mm (¾-in.) size for packaging tape. The system can also produce 60 rolls of 24mm-wide (1 in.) tape every 25 seconds. After slitting and rewinding for the specified length, the rolls are hand-inspected for quality and then packaged for shipment. Rolls can be pulled for sale as seconds if they are short or if the edges are not sharp, but they still must have the specified adhesives and release coatings.

The inspection light has proven to be a versatile tool for a variety of needs. "It was very easy to install and to get people in the plant to use it," says Stan Williams, technical projects manager for Shurtape. "It has enabled us to control overcoating and repeating defects, and it has helped us with our printing. We can get a finite look at everything even though we change plates frequently. We can always see when something is out of register. We couldn't look at all of our zones effectively without it."

Going beyond the fixed-mounted HD 851, Williams said Shurtape has begun using hand-held Unilux Miti-Lites for spot-checking at the Hudson plant, which has an 80-in. web. With the hand-held, battery-powered Miti-Lites, operators zero in on the causes of problems and correct them as early as possible in the value-added processing line. This is particularly beneficial when machines run 5,000 yards of material before it reaches the inspection station.

"With the Unilux, we can see what's going on in the entire run of a product," notes Clarence Sanders, QC manager. "If need be, it tells enough so that we can shut down a run if we have to and fix it right away. Then we can resume without defects."

Inspection is likely to increase in importance as Shurtape develops new products for both new and existing markets. The company has recently introduced a UV-resistant tape for painting applications and a specialty tape for the demanding circuit-board manufacturing industry.

"Every tape has value-added processes," Patterson says. "In our highly competitive markets, we simply can't afford defects and the waste and customer-service problems that defects create. Quality is critical, and Unilux gives us the inspection capability to find defects and fix them as early in the process as possible—when it's most cost-effective."

FOR MORE INFORMATION

UNILUX, INC., 201/712-1266, fax: 201/712-1366, www.unilux.com