A bright new idea for smart card productionA bright new idea for smart card production

Cham, Switzerland--Who says you can't eat your cake and have it, too? The Swiss company Sempac SA proved it possible by developing a new concept for producing smart cards economically, whatever the batch size.

Traditionally, printing companies have manufactured these magnetic stripe cards using pre-molded card bodies or bodies punched from extruded sheets. This process requires several steps, including printing the cards and then providing them with a chip module.

Challenging conventional thinking, Sempac SA devised a technique for producing the cards by adapting proven injection molding techniques. Its process involves placing a chip module and preprinted labels into a mold, injecting a resin, and joining the layers using low injection pressures (between 800 and 1200 bar) and temperatures (290C maximum).

The challenge involved coming up with a polymer with extremely high flow properties, good mechanical properties, and the ability to maintain high dimensional stability.

Ronfalin(reg), an ABS by DSM Performances Polymers (The Netherlands), proved able to meet the stringent ISO standards for smart cards. The material has a tensile strength of 41 N/m(super2) and a melt flow index at 220C and 10 kg of 55 degrees/min. Further, it can hold dimensional tolerances of plus or minus 0.0005 mm in all directions.

Adhesion is good, and the coefficient of thermal expansion mismatch between the polymer and the module is not an issue, due to a clever chip design that involves side anchors.

The obvious advantage of this approach, of course, is that Sempac SA can easily change production lot sizes with virtually no interruption in the production process. It may be making telephone cards one minute, and bank cards the next.

Moreover, by using a four-cavity mold and handling, the throughput rate is approximately 3,000 cards per hour. Production costs, are roughly comparable to traditional smart card fabrication techniques.