Busener started researching adhesives that would offer better heat and cold resistance, and a stronger bond to nonporous substrates than the industry-standard ethylenevinyl acetate. He found that polyurethanes offer heat and cold resistance at 150 to -40 C.

However, the same chemical properties that make polyurethane a good choice for strength and performance also pose challenges during material processing and application. Busener had difficulty finding an adhesive dispenser because of the adhesive's premature curing, charring and maintenance problems. He turned to Nordson Corp. (Westlake, OH), which supplied the company with an adjustable, closed, extrusion slot-nozzle system.

The system comprises a closed edge-banding system, which replaces the roller and open glue pot with adjustable slot-nozzle technology for precise adhesive application and reduced maintenance. The system also includes a MC Series applicator for polyurethane processing, an EB60V adjustable edge-banding slot gun for applying the material and a PLC interface to the parent machine.

The PLC interface predetermines leading and trailing edge patterns. Panels are fed into the edge-banding machine, and the EB60V gun is triggered to start and stop dispensing at the preset points, based on the panel length. The positive application pressure to the panel provides accurate and repeatable coating, with consistent coating weights.

"You can assign a glue-line width and height to each specific panel, without stopping to change a shim blade. With the PLC interface, the predetermined starting and stopping points are infinitely variable and very precise," Busener says. "There's also no corner build-up or excess glue on the panel. It's a very clean, controllable process."

Eliminating rollers and open glue pots also eliminates airborne contamination. As a result, the closed configuration reduces production costs associated with maintenance, cleaning and labor. With few moving parts, maintenance and repair is simpler. In addition, the MC Series applicator provides even processing and constant adhesive viscosity for high bonding quality. The temperature control prevents adhesive charring and premature curing, eliminating adhesive waste.

According to Busener, the company is now more productive because downtime for changing panel sizes and routine maintenance is drastically reduced. He also attributes reduced material consumption to the system's controlled application process and the elimination of material waste when cleaning the glue pots.

"The bottom line for me is that I'm putting out a better product," Busener explains. "I'm getting a better bond with the polyurethane and better appearance because there's no excess adhesive being used."

For more information on dispensers, call Nordson Corp. at 440-985-4000, visit www.nordson.com or Reply 3.