Flex circuit provides cost-effective solution for Military relay manufacturer

Product: Flex Circuit
Market: Military
Application: Electric Relay

A manufacturer of electrical relays for Military applications came to Minco with no experience in designing flex circuits. The customer wanted to replace the hard wiring in 2A and 4A relays with flexible printed circuits. They sent Minco a hand wired unit which Minco's Design Engineer in our Flex Prototype Group used to design the circuit. Wrapping the heavy wire around the pins, soldering them, and routing the wires correctly was a time consuming assembly step, which Minco's flex circuit eliminated.

The four layers of conductors running from the relay to the connector are accomplished with a two layer circuit. Both ends of the circuit fit one on top of the other on the relay’s pins; the stiffener and solder pads, in the center of the circuit, fit on the connector. The design keeps down the layer count while providing enough room for the wide conductors. The circuit is etched on 2 mil thick copper and plated to 3 mil. The conductors are thick and wide to meet the current carrying requirement.

With the circuit terminations installed one on top of the other, this two layer design functions as a four layer circuit. Pictured above is a side view drawing showing how the circuit flexes and mates with connector pins.