Is there a PCB construction that creates an area of the board that can easily be broken?
In the sketch the dotted section could be easily broken to reduce the size PCB. My design would have each breakout section containing a button(s) that wire back to a single edge connector. Breaking off pieces of the PCB reduces the number of buttons.
I was wonder if such a technique is used and what it might be called when constructing a PCB?
Hi Sean,
There are lots of options, for instance if you need enough of them, (e.g. in the tens of them), economically it may just work out that getting a load of them in different lengths is cheaper, as Andrew says, the costs are so low for a basic board, there is less reason to make them with the snap-off capability. I had a board with several different sections, but I gave up and just ordered 50 or so of each of the sections, and even if some go unused, it was still cheaper. Personally I like this option, because it's cheaper production since there are less operations, and the boards are easier to use because they do not need sanding etc after they have been snapped off (not essential, but it bothers me if I don't.
Another option is to make the board the minimum size but easy to solder together (if you're not using the board shape for strength too), for instance for touch buttons, I went with a 2x2 array, and the boards can be fitted next to each other for (say) a 2x4 array. In that case, I used a separate cheap connector on each board though.
Often with the drilled hole method, it can be combined with slots, i.e. the board may have slots, and then some small holes (mousebites). There will likely be examples of it online, with suggested dimensions. Some development boards do a similar thing, to (say) snap off the debugger from the rest of the board
The guillotine idea is nice too. It will flex the board slightly, but for the size of board and the use-case, it's likely no issue. It's more effort though, compared to a load of ready-made boards of the right dimensions.
Incidentally, for some projects, as a more far-out idea, perhaps aluminium PCBs are another option too, since they are getting to be very low-cost, e.g. if you want to make board that can be broken off by metal fatigue with a sharp bend along holes, but can also be used to take on a different shape through smaller angle bends. I experimented a little bit with aluminium PCB bends here: XR-1000 Chassis and Electromechanicals: Putting it Together however I still need to learn more about that. One would probably need to initially experiment with a few iterations to make it a useful technique for their end application (if it is usable at all, because it has some significant limitations too).
Examples from an eval board (TI FDC sensor board). The left and right side pads are connected on the underside, I've drawn red lines to show the traces. They used slots to make the board easier to snap off, because the small holes on their own would be difficult to snap apart with hands.
(image sources: TI website)
Here they used large slots:
Hi Sean,
There are lots of options, for instance if you need enough of them, (e.g. in the tens of them), economically it may just work out that getting a load of them in different lengths is cheaper, as Andrew says, the costs are so low for a basic board, there is less reason to make them with the snap-off capability. I had a board with several different sections, but I gave up and just ordered 50 or so of each of the sections, and even if some go unused, it was still cheaper. Personally I like this option, because it's cheaper production since there are less operations, and the boards are easier to use because they do not need sanding etc after they have been snapped off (not essential, but it bothers me if I don't.
Another option is to make the board the minimum size but easy to solder together (if you're not using the board shape for strength too), for instance for touch buttons, I went with a 2x2 array, and the boards can be fitted next to each other for (say) a 2x4 array. In that case, I used a separate cheap connector on each board though.
Often with the drilled hole method, it can be combined with slots, i.e. the board may have slots, and then some small holes (mousebites). There will likely be examples of it online, with suggested dimensions. Some development boards do a similar thing, to (say) snap off the debugger from the rest of the board
The guillotine idea is nice too. It will flex the board slightly, but for the size of board and the use-case, it's likely no issue. It's more effort though, compared to a load of ready-made boards of the right dimensions.
Incidentally, for some projects, as a more far-out idea, perhaps aluminium PCBs are another option too, since they are getting to be very low-cost, e.g. if you want to make board that can be broken off by metal fatigue with a sharp bend along holes, but can also be used to take on a different shape through smaller angle bends. I experimented a little bit with aluminium PCB bends here: XR-1000 Chassis and Electromechanicals: Putting it Together however I still need to learn more about that. One would probably need to initially experiment with a few iterations to make it a useful technique for their end application (if it is usable at all, because it has some significant limitations too).
Examples from an eval board (TI FDC sensor board). The left and right side pads are connected on the underside, I've drawn red lines to show the traces. They used slots to make the board easier to snap off, because the small holes on their own would be difficult to snap apart with hands.
(image sources: TI website)
Here they used large slots:
