New-Tech Europe | Oct 2016 | Special Edition For Electronica 2016

of contact, usually three to four “fingers.” (FIGURE 1: Multi-finger, heat-treated BeCu contact for high cycle applications) At the other end of the spectrum, some interconnect systems have a relatively stress-free life with few cycles, possibly in an office environment. A single beam contact system is usually sufficient for these types of applications, and if it is made of phosphor bronze or beryllium copper, it will usually withstand up to 100 cycles. A third contact option is one designed for high-retention, or “rugged” applications. The geometry of the contact beams increase the normal force and withdrawal force of the mating terminal. Long beams and therefore extended insertion depth make it rugged. (FIGURE 2:

Phosphor bronze contact designed for rugged applications.) While the focus of this article is contact design, we would be remiss if we did not mention insulator design in any discussion of rugged interconnect applications. Plastic insulator design features that are useful in environments requiring rugged connectors include: • Board locks on connectors that mechanically lock two together two printed circuit boards. • Positive latching systems on discrete wire and IDC cable systems. Manually activated latches can increase unmating force by up to 200%. • Screw downs which secure the connector mechanically to the board. • Weld tabs, which significantly

FIGURE 1: Multi-finger, heat-treated BeCu contact for high cycle applications

FIGURE 2: Phosphor bronze contact designed for rugged applications

FIGURE 3: Rugged features on insulators which increase the ruggedness of the connector

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