New-Tech Europe Magazine | Jan 2018

Direct Connection onto the PCB The new REDFIT IDC plug connections with SKEDD technology

Daniel Kübler, Würth

In 2013 Würth Elektronik ICS introduced SKEDD, a new direct connection technology that is solder-free and uses IDC, they now share this new design with its big sister Würth Elektronik eiSos. This unique industry-wide solution allows for quick board mount, assisting in cost-effective firmware updating for microcontroller programming after assembly. Soldering and press-fit technology are the most common methods for establishing a connection between the PCB and a component or plug connector. In both technologies, a mating connector is permanently pressed or soldered onto the PCB on which the components are then attached. Both variants are suitable for automatic assembly but this time-saving advantage also entails some disadvantages. The THT

soldering process, for example, is not only complex, but also applies thermal stress to the electronics. The mating connector generates higher costs as well, let allown the preparation requires an assembly process that takes up valuable installation space. SKEDD technology eliminates all these disadvantages in one simple package. Simple yet reliable, it allows the plug connector to be connected to the PCB directly and released again by hand; without a mating connector. The trick with the right force In order that the plug is connected properly to a PCB using SKEDD, and allowing connection to be released again with multiple mating cycles, the connection solution has to fulfill three conditions:

Simple and convenient pluggability, even for connectors with a high number of poles (Picture 1a) The forked SKEDD contact has two adjustable arms. Their shape is essential for the force relationships in plugging the contact into the PCB. When plugging into the PCB, the SKEDD fork starts open; the elasticity comes from the curvature of the vertex. This is designed such that the SKEDD contact can be plugged in the Via with low force. The normal contact force has to be sufficiently high to establish a stable connection (Picture 1b) During the plugging process, the SKEDD arms begin to conform to the opening. At the end of the insulation process, in the plugged state, the spring stiffness of the SKEDD contact attains its maximum value, making the SKEDD contact

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