New Wire-to-SMT Board Terminal Featured at ATE 2007
By John Colwell, Bishop & Associates Inc.

At the recent Assembly Technology Expo in Chicago, Zierick Manufacturing Corporation introduced what is believed to be the newest and most economical way to terminate discrete wires on surface mount (SMT) printed circuit boards. The product is a surface-mount, insulation-piercing terminal and termination tool that combine the advantages of crimping, insulation piercing, and surface-mount technology, resulting in reduced production costs, improved reliability, and increased processing speeds.

Surface-Mount, Insulation-Piercing Terminal (Zierick Manufacturing Corp.)

While the product can be applied wherever a wire needs to be permanently connected to an SMT printed circuit board, the most popular utilization is for instances where the wire passes through the terminal and numerous serial connections are made. Examples of this type of application are channel block lettering (iIllustrated at the right) and LED lighting devices, where a series of LEDs are attached to a pair of wires.

Compared to conventional methods, the new system is less expensive than a two-piece, pin-and-socket connection or an IDC (insulation displacement connector) type of connection, which provides strain relief. According to the manufacturer, it is more cost-effective than soldering wires to a board by hand, and utilizes about the same board real estate as a hand-soldered connection.

Moreover, the new insulation piercing terminal provides a highly reliable connection, as it uses a well proven crimping technology with unique Insulation Piercing Spikes (IPS). The IPS inside the terminal penetrate the wire insulation to the core of the wire, and provide a gas-tight connection during the crimping process. With this method, there is no need to strip the insulation from the wire and the termination can be made not only at the end of the wire, but at any place along the length of the wire.

Physically, the terminal consists of a flat base with two sidewalls perpendicular to the base. Two insulation-piercing contact spikes protrude from the flat base. Between the contact spikes is a flat area to facilitate vacuum pick-up and terminal placement. There are two deep score lines near the transition area between the sidewall and the base of the terminal.

The new Zierick process begins with the terminal being placed on the SMT board together with the other required components. Recommended solder pad geometry is only 0.235 (5.97mm) by 0.110 (2.79mm). After the assembly goes through reflow, it is moved to the terminating machine, which feeds the wire into the terminal and crimps the terminal sidewalls over the wire.  

In the process, the insulation-piercing spikes penetrate into the wire without the necessity of removing the insulation. The spikes make contact with the wire strands. The crimp not only facilitates the contact, but also provides excellent strain relief for the wire. The two score lines on the terminal wall ensure that no deformation is introduced near the edge of the solder fillets, thereby preventing cracking and peeling of the solder joint.

Termination Tool (Zierick Manufacturing Corp.)

The termination tool not only terminates the wire, but also feeds or stitches the wire into the terminal, completely eliminating any work related to wire handling.      

The crimping tool footprint is illustrated above, along with the printed circuit board clearance requirements.

The product is available in loose piece (P/N 1286) and on tape (P/N 1286T). The Zierick Surf-Shooter SMT loose piece pin feeder, shown at the left, feeds surface mount loose piece pins ranging in size from 0.025" (0.64mm) square to 0.080" (2.03mm) in diameter, up to 0.750" (19.05mm) in length, at feed rates greater than one pin/second.

The Surf-Shooter SMT presentation unit is 3.750" (95.25mm) wide and is readily mounted in the feeder bay of most flexible placement systems, including Siemens, Universal, and Europlacer machines.

More information about this and other Zierick products can be found at www.zierick.com.