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.
Continuous and extremely homogenous material transition between press pin and through-hole plating.
- With regards to long-term reliability, the press-fit system is convincing since it has the lowest FIT value (Failure in Time) of the overall system. It is up to 30 times better than that of an SMT solder joint. A single solid press pin has a typical extraction force of 100N or approximately 70% of the insertion force. Therefore press-fit connections are predestined to provide not only electrical but also mechanical connection solutions for electrical components.
Advantages of the Press-Fit Technology
- Very high ampacity, ideally suited for high continuous and peak currents
- Press-fit connections show extremely high environmental stability
- Low-resistance connection (< 200 µΩ) means low self heating, hence less heat must be dissipated through the system
- No heat development on sensitive components and no thermal stress of the circuit board
- Extremely stable mechanical
- No problems with cold solder joints
- High mechanical retaining forces
- Double-sided mounting of circuit boards is possible
- Much higher long-term reliability as for solder connections
- More secure than soldering and screw connections
- No changes in the production of circuit boards necessary
Using the Würth Elektronik power elements, currents of up to approx. 300A can be transferred to the printed circuit board. These power elements provide wide-ranging application options.
|Option for fitting a fuse||High current Board-to-Board connection|
The processing of press-fit elements fits seamlessly into the production process and is thus very cost-effective. Multiple power elements can be fitted simultaneously using press-fitt tools. Compared to soldering, the printed circuit boards are not subjected to thermal loads.
If not stated otherwise in the drwaing, the Würth Elektronik power elements have quadratically designed press-fit pins. The through-hole plating in the PCB must therefore have the following characteristics:
Our power elements are designed for the press-fit system. Alternative processing methods, such as soldering, are not contemplated.
as per IEC 352-5
Max. 250 N per pin,
min. 40 N per pin
Min. 30 N per pin
|Via specification for chemical surfaces||Via specification for HAL|
Power elements in Press-Fit Technology
|Material: Brass (CuZn39Pb3)|
|* The Ultimate Torques can be taken from DIN 267, Part 25|
|Derating Measurement for Power Elements|
|* Operating current is defined by the PCB, cross section of the cable and cable lug. Suggested cross section according to VDE 0100 on page 153.|
Get the AppNote as pdf version here