Why overmolding is a key issue in the design of interconnect solutions

8 Sep 2021

A reliable and robust electrical connection requires more than cables and connectors. Depending on the application and the environment, a better solution may be to develop special connections with inserted or overmolded pins. Electrical contacts can be totally protected by a plastic overmolding made from a material selected to meet mechanical or environmental protection and space constraints. The protective function of this overmolding feature is essential to ensure the reliability of the connection. Overmolding can also be an asset to adapt and facilitate the integration of the connection into the customer’s system.

Connecting without a connector

For connections on printed circuit board assemblies (PCBA), the use of standardized connectors is typical but, depending on the size and the specific customer requirements, customized interconnect solutions may be necessary.

Unit pressfit contacts

 The pressfit contact solution on a circuit board is one of these solutions. A stamped contact with the pressfit function (eye-of-the-needle) is inserted into the plated hole of a PCB without the need for additional soldering operations. This insertion can be automated with the integration of dedicated machines into the assembly lines.

The design study allows the designer to define the size of the contact according to the current required for the application. Qualified pressfits of different thicknesses and platings are used to meet customer specifications. The PCBA with its pressfit contacts is then assembled into a plastic housing. This solution reduces the cost of the connector function and provides a perfectly integrated unit.

Overmolded pressfit contacts

Overmolded connections to fit the customer’s needs can also be considered. The co-engineering phase plays an essential role in the definition of the product: optimization of the geometry of the parts with the help of rheology software and choice of materials (PA, PBT, PPS, PPA, and others) in relation to the various constraints.

The overmolding joins together a set of parts while guaranteeing mechanical integrity and providing resistance to a variety of conditions such as shock, abrasion, chemical products, radiation, temperature, and moisture ingress.

Complex interconnects without connectors

The use of connectors is not always required, even for complex links. Interesting alternative solutions can be implemented. Special housings with contacts crimped or soldered to an extruded cable, which is itself overmolded, in line in continuous or semi-automatic mode, are among the custom-designed solutions that connector and cable manufacturers who have integrated this expertise are able to offer.

Read our full article "Why overmolding is a key issue in the design of interconnect solutions" in Connector Supplier's September 2021 Connectivity components ebook