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Story 144 – 2000 – Products

Stable connections through flexibility

Press-fits combine many properties

Press-fit connectors are increasingly replacing the soldering of printed circuit boards. The high demands on the formability of the material require special strips which Wieland produces according to the exact specifications of the customers.

The times when electronic components were soldered onto printed circuit boards are largely over. The connection of the printed circuit boards with other components is now also usually done with so-called press-fits, small plugs that are pressed into corresponding holes (vias). This creates an electrically and mechanically stable connection – quickly, cost-effectively and without time-consuming soldering.

The prerequisite for this is not only the good electrical conductivity of the connectors, which is ensured by bronze or high-performance alloys. The mechanical properties of the press-fits are also decisive: On the one hand, they should be able to be pressed into the vias with little force, and on the other hand the connection should be reliably stable. This is achieved by a spring force that the connector head develops thanks to complex geometries. The production of these "flexible press-fit zones" therefore requires complex, sometimes considerable forming, which places very special demands on the material – not least in terms of maintaining low tolerances.

Individually tailored to customer requirements, Wieland supplies press-fit manufacturers mainly with strips in thicknesses between 0.60 and 0.64 millimetres. They are ideally suited for the production of press-fit connectors for the vias which usually measure one millimetre. The increasing use of press-fit technology has now also led to other dimensions. On the one hand, a trend towards ever smaller connectors requires strip thicknesses of just 0.2 millimeters. On the other hand, press-fit connections are now also used in power electronics modules for transmitting large currents. These press-fits are then manufactured from strips with thicknesses between 0.8 and 2.0 millimeters.

Whether with the smallest or relatively large dimensions, the special requirements on the electrical and mechanical properties of the strips remain a challenge which Wieland meets through constant further development.

heads of connectors with flexible press-fit zones

The heads of the connectors are designed as "flexible press-fit zones" due to complex forming processes, which ensure secure connections by means of spring force.

Press-fits

Press-fits require special mechanical properties of the strips made of high-performance alloys. They are developed and produced exactly according to customer requirements.