When these pins are pressed into a plated through-hole, the points (the major or circumscribed diameter) of the polygon are set or imbedded in the hole while the flat sides of the feature (minor or inscribed diameter) provide relief, allowing the remainder of the plated through-hole barrel to remain intact. The result is that internal board layers are not disconnected when the pin is pressed in. With a properly specified hole size, the polygon shaped press-fit feature will allow the pin to be secured in the hole while maintaining continuity throughout all the layers of the PCB.
Mill-Max employs its machining skills to manufacture either square or hexagon shaped press-fit features to suit a variety of hole sizes and assembly requirements. Square press-fit features normally leave a larger gap between the flat side of the feature and the hole, useful for solder flow and venting of gasses, while a hexagon feature will provide more interference and greater retention.
The pins are used in applications with more demanding mechanical or electrical requirements, such as power supplies, power converters and any device subject to blind mating or rough handling. They are typically staked into a PCB at the press-fit end and either soldered or plugged in at the pin end. The smallest pin diameter in the group is .040 inches, while the largest is at .080 inches — typical sizes for DC-DC converters. These pins are suitable for high current applications, the limits of which depend on the temperature requirements and heat sinking abilities of the environment. The pin material is typically brass, but for greater electrical conductivity and more efficient heat dissipation tellurium copper is also available.