Originally Published MPMN May 2009

BREAKTHROUGHS

Electronics Supplier Has Good Connections

Bob Michaels

Zierick Manufacturing Corp. was determined to improve the process of connecting wires to printed circuit board (PCB) assemblies, a procedure that involves large, complicated components and must often be performed manually. Through its efforts, the company developed a product that not only simplifies and miniaturizes PCB wire connections but also has won a metal-forming award.

Zierick’s metal-stamping-based system for connecting wires to surface-mount PCBs consists of a flat base for solder adhesion and two sidewalls perpendicular to the base that serve as crimp ears to hold the wire in place. In addition, the component contains two insulation-piercing contact spikes that protrude from the flat base and contact the conductor after they pierce through the wire’s insulation and make an electrical connection. The connector also features two grooves in the transition area between the crimp ears and the terminal base, which ensure that when a wire is crimped into the terminal and the ears are formed around the wire, the solder joint will not experience stress cracking.
“The system works by crimping the wire with the crimp ears,” comments Janos Legrady, Zierick’s vice president of R&D. “Instead of having to strip the insulation from the wire, there are spikes in the crimp ears. When you form the ears around the wire, the spikes penetrate the wire and make the electrical connection.” The rest of the crimp material also provides very good strain relief, Legrady says. “You can pull the wire and bend it or move it, but you do not transfer the movement to the connection area.”
Wires are typically connected to PCBs using bulky barrier blocks, pin-and-socket assemblies with two separate connector components, insulation displacement connectors, or hand-soldering methods. “Until now, we didn’t have a good solution for connecting a wire to a PCB,” Legrady remarks. “Connections were made using a complex screw and plastic housing process that was both expensive and clumsy. We saw the need to address the issue of terminating a wire to a PCB in an inexpensive way that would not take up more room than a hand-soldered connection.”
In addition to their assembly limitations, some conventional techniques for connecting wires to PCBs, such as insulation displacement connectors and hand soldering, do not ensure the connection against electrical failures caused by vibrations or other types of strain. In contrast, tests show that Zierick’s crimp terminal offers failure-free connectivity.
“My favorite test involves subjecting the component to a high number of thermal shocks,” Legrady notes. “When thermal shocks occur, there is always movement in the connection in the form of expansion and contraction. A high number of shocks will break down substandard connections.” Zierick’s engineers performed 500 hours of thermal shocks, subjecting the component three times an hour to temperature shifts ranging from –60° to 120°C and measuring the connection’s contact resistance before and after the shock. “During this torture test,” Legrady states, “resistance increased less than 10%, which indicates a very good connection.”
As a result of its wire-to-board technology efforts, Zierich has been named the 2009 recipient of the Higgins-Caditz Award by the Precision Metalforming Association.

Zierick Manufacturing Corp.
mount kisco, ny
www.zierick.com
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