While the trend of industrial electronics is toward utilizing surface-mount methods, Press-In PC-board terminal blocks present an alternative to surface-mount devices.

Conventional PC-board terminal blocks are usually placed on the board with the pins inserted through plated holes. A wave-form process solders the pins underneath directly to the board.

With Press-In technology, a press inserts Press-In PC-board terminal blocks into plated through holes. During fitting, the pins' C-shaped cross sections constrict to pass through the holes. When the block is fully pressed into place, pin lengths below the holes expand back to their original configuration--securing the block. The easy-to-use method requires no soldering, lowering cost, and eliminates soldering faults, flux problems, and additional cleaning.

The mechanically stable Press-In technology supports large industrial OEMs who have board-space and cost constraints. Double-sided assembly is possible, with no additional fixing techniques, such as retaining clips.

Press-In blocks come in sizes ranging from high-density, 0.150-inch, to 0.200-inch spacing. They require from 11.2 to 13.5 lbs/pin for insertion and come in many styles and pin positions. Phoenix Contact supplies the required header tools as well as the Press-In PCB terminal blocks.

To contact a Phoenix Contact product engineer, call 800-322-3225 or fax 717-944-1625.

Proper placing multiple PC board connectors

by Lou Castagna, Project Engineer AMP Inc., Harrisburg, PA

Designers commonly must place more than one pair of connectors between a pair of PC boards. Most connectors are not designed for such multiple applications, leading to misalignments and non-connecting "stubs" or high mating forces.

An analytical procedure can help determine acceptable placement tolerances. Screening connector systems before verification testing, the procedure manipulates connector dimensions. Placement tolerances are determined to yield a functional system. The procedure treats PC boards with multiple connectors as statistical series systems. With more connectors, placement tolerance of each connector becomes stricter.

In reality, marginal mating interference is absorbed by flexing of plastic and contacts. To approximate actual conditions, the procedure permits designers to assign an allowable interference value.

To speak with an AMP applications engineer, call 800-522-6752, fax 717-986-7575.