Parametric PCB base

thingiverse

Parametric PCB base =================== The master location for these files is https://gitlab.com/wjcarpenter/3dprinting/-/tree/main/parametric-pcb-base They are also available at https://www.thingiverse.com/thing:5713009 For a project I was working on, I was well on the way to designing a custom enclosure. I did a lot of work on the base to hold the PCB. When I was looking around for something to help with a detail of the rest of the enclosure, I came across mrWheel's YAPP_Box project, https://github.com/mrWheel/YAPP_Box, which does everything I was planning, plus a lot more. So, I am not even using this design myself, but some of the OpenSCAD things I figured out along the way (especially threaded spikes and donuts) might be useful to someone in some context. This is a parametric design for a flat base to hold a PCB. It has 4 posts for mounting the PCB and also to provide stand-offs from the base. If you 3D print this, don't forget to allow for shrinkage of your filament material, else it won't match the PCB mount holes. (For shrinkage, I recommend using precise dimensions here and enlarging the design by some percentage in your 3D print slicer.) In OpenSCAD preview mode, the parts are colored to make it easier to understand what this description is about. - base: blue - stub: red - spike: green - donut: orange - grid holes: invisible :-) The base and mount hole positions can be taken directly from the kicad PCB layout. In kicad, the Y axis starts at the top of the page and increases toward the bottom. There's also generally an overall offset from a (0,0) origin. The SCAD layout is moved to a mostly (0,0) origin and is reversed with respect to the Y axis. You might not notice that since the board is likely to be symmetric both horizontally and vertically. For the PCB mount holes, there is a cylinder or square that holds the PCB away from the base. It's called the stub and has a slightly larger diameter or side than the mount holes that rest on it. Emerging out of the stub is another cylinder called the spike, which can be threaded. The spike is slightly smaller than the mount holes. The idea is that you can put the spikes through the mount holes so that the PCB rests on the stubs. You just need enough height for the stubs to keep any through-hole solder areas from touching the base. You just need enough height on the spike to pass through the PCB and be held in place with hot-melt glue or something. (If you were careful, you could melt down the top of the spikes to hold the PCB in place.) You can also use donuts slipped over the spikes to hold the PCB in place. The donuts and the spike can either be smooth or have matching threads. To use threads for the donuts and spikes, see the "use_threads" config item below. If you choose to use that, you must obtain the threads.scad library from https://github.com/rcolyer/threads-scad and put it in one of the locations described here: https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Libraries (The simplest is to put it in the same directory as this file.) If you don't use threads, you can simply comment the "use" line out. (Or you can leave it as-is and ignore the warning given by OpenSCAD.) In 3D printed parts, there is always a worry about precision for parts that need to fit together. That's why the parameters below include separate items for adding or subtracting a little bit from some dimension. You may need to experiment a little bit on your 3D printer to get things to fit nicely. The default settings are what make my 3D printer happy, but yours may be different. To help with experimentation, see the "just_one_corner" config below. There is also a grid of rectangular holes in the base. You might use them to mount the base somewhere with cable ties or something else. If you don't want those holes in the base, just put a quantity of 0 for either X or Y (or both).