Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

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Soldered PCB jumpers



Soldered PCB jumpers | 23 November, 2001

We are currently handsoldering PCB jumpers. Does anybody have any experience on how the PCB-pad footprint design should be for screenprinting PCB jumpers to ensure that the connection is soldered?

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Soldered PCB jumpers | 26 November, 2001

Depends on what you're talking about. For instance:

Jumpers between pads: Why not use SMT jumper components?

Long ECO jumper runs: When we have a serious problem in the design of our boards, we contract thick film additive jumper work. Search the fine SMTnet archives for contacts, for instance:

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Soldered PCB jumpers | 27 November, 2001

The reason why we are using soldered PCB jumpers is that it is cheaper than dip-switches, 0 ohms resistors, etc. Field updating is also easier. We are producing different variants of some of our products. It would nice if we could presolder the PCB jumpers on the most common variant by screenprinting solderpaste on to the pads. In combination with that we are looking for a suitable PCB pad design which ensures that the solder paste, when applied, does make the desired connection.

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Soldered PCB jumpers | 27 November, 2001

Oooo, I get it. We do that trick on the wave solder side of boards.

On the bare board, during design / layout, the basic shape of the jumper is a 125 thou disc of copper [that of course is eventually covered with whatever solderability preservative we use on the board]. The disk is usually divided into two half discs, but sometimes we see quarter discs. Designers divide the disc in: * Half with a 20-25 thou etch of the copper through the center of the disc. * Quarters with two perpendicular 20-25 thou etches of the copper through the center of the disc.

You need to save the fraction of a cent that it costs for a zero ohm resistor? Yeow!!!!

Doing this on the primary side, you'll probably want to experiment, depending on the stencil thickness and all that, but printing a round aperture maybe 250 thou on the jumper disc should do it.

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Michael Parker


Soldered PCB jumpers | 27 November, 2001

rather than applying jumpers, try thinking it another way.

Have all possible jumper connections pre-made by the fab design. Use an exacto or dremel to "open" the undesired paths by removing a bit of copper trace. total flexibility, only one fab makes multiple assemblies. No need to worry about open or insufficient solder joints that don't operate electrically.

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