Today we had an presentation from Würth about Press-Fit. So what is Press-Fit ?

As a solder free fastening technology, press-fit technology frequently offers an attractive alternative to simple soldering technology. An effective electrical press-fit connection is created by pressing a pin into the plated through hole of a circuit board and – as part of cold welding process – generating a gas-tight electrical connection.

The trough-hole plating for a press-fit system is essentially made in the same way as are the holes for accepting components for THT soldering. Thus there are no changes required in the pcb manufacturing process. One outstanding characteristic of the press-fit system compared to the soldering system is that it produces not only an electrical connection but also an extraordinarily strong mechanical connection between the inserted components and the pcb.

Source: https://www.we-online.com/web/en/electronic_components/produkte_pb/application_notes/powerelemente.php