Membrane-pressed MDF panels fill the bill; converting from metal powder finishes to thermoplastics re-defines the appearance, durability and repairability of Sprint's bill payment kiosks

Wood & Wood Products, Nov, 2004

In the high traffic environment of wireless retail stores, automated bill payment kiosks fabricated of powder-coated sheet metal incurred scratches, dents, scuffs and stares from pens, markers and spilled drinks.

"As a result, wireless companies were incurring high costs to replace damaged kiosks or repair them in the field," says Tom Zaken, director of national program development at Creative Kiosk, Norcross, GA.

One of Creative Kiosk's wireless customers is Sprint. The company accepts tens of thousands of payments each month through the kiosks, providing convenience for customers and sales personnel alike.

Sprint's typical wireless bill payment kiosk incorporates a processor, software, bar code reader, touch screen interface, automatic cheek accepter, bill accepter and check-writing counter. At any one of Sprint's 450 nationwide retail stores, the customer can scan the bar code on his or her bill or enter the phone number, credit card number or other identifier. The kiosks accept payment by cash, check, credit card or debit card; credits the customer's account; and prints a receipt.

NCR Corp., which provides kiosks for Sprint and other wireless companies, approached Creative Kiosk in an effort to improve both the appearance and the durability of its kiosks. Zaken says, "NCR wanted something smoother, more branded, with a flashier finish. We recommended membrane pressed MDF boards based on our excellent results in applications such as airline e-ticket kiosks and movie ticket kiosks."

As a result, Sprint wireless stores now provide a new generation of kiosks that withstand more punishment than previous sheet metal units and, when damage does occur, allow easier field repair at a lower cost.

Improved Performance

Creative Kiosks employed radically different design parameters and fabrication methods. Instead of relying on powder-coated sheet metal housings to satisfy cosmetic and structural requirements, the company's latest kiosks utilize an internal steel future for support and abuse-resistant, membrane-pressed MDF panels for the kiosks' exterior.

The kiosk panels consist of 3/4 inch MDF board, normally melamine-backed, that is CNC-routed to produce 3 D shapes, then surfaced with 1mm heavy-gauge Kydex L protective thermoplastic sheet that conforms to all top and side surfaces of the routed substrate. The resulting seamless panel is impact resistant, chemical resistant and, if all else fails, replaceable in the field.

The proprietary thermoplastic alloy exhibits notched Izod impact resistante of 15 ft-lb/in. (801 J/m) (ASTM D-256), tensile strength of 6,100 psi (42 MP/a) (ASTM D-638) and Rockwell Hardness 94 (ASTM D 785).

Membrane pressing causes the sheet to conform to all 3-D surfaces routed into the MDF board, including compound curves, intricate profiles, sharp details, undercut edges and wire management holes routed completely through the component. It is also easy to rout brand identification into the substrate and encapsulate the graphic with protective surfacing material at no additional material or labor cost.

"It's like taking the handcuffs off of our designers," says Zaken, whose company specializes in the manufacture of interactive kiosks. "Without the limitation imposed by materials that bend only in one direction, designers can create virtually any three-dimensional shape, satisfying objectives that were once mutually exclusive."

In addition to designing components that are stylish, designers can ensure that the kiosks are ergonomically correct, without the unsafe corners or sharp edges associated with sheet metal. The redesigned bill payment kiosks are also safe and attractive with soft-looking rounded edges and corners, as opposed to sheet metal units "that looked like cold sheet metal boxes," Zaken says.

Manufacturing Benefits

Membrane pressing holds a manufacturing advantage over sheet metal fabrication, allowing production of panels in short time frames and short runs of tens or hundreds of units, typical for kiosks. It is also a relatively quick, semi-automated process compared with labor-intensive sheet-metal fabrication.

Piedmont Woodworking, a manufacturer of value-added, membrane-pressed components based in Rutledge, GA, pressed the kiosk panels and machined them on a CNC router for Creative Kiosk.

John Colby, general manager of Piedmont Woodworking, says that Kydex sheet is easy to membrane press. "It confroms to outside corners and deep recesses without thinning, maintaining uniform wall thickness and impact resistance in these areas." Kydex sheet, in a standard red color that matched Sprint's corporate red color, did not fade, deform thin or break like other materials when stretched around a corner or curve, Colby adds.

The Process

Membrane pressing encapsulates all but the bottom surface of flat or 3-D wood-core substrates by causing thermoplastic sheets to conform and adhere to all tops and side surfaces, including rounded corners, sharp profiles and fine details (even wire management holes routed completely through the substrate).