This is just a simple project I did to make a small fence that fits on the side of the bed of my cheap Chinese CNC router. I decided to make them so that I can keep material aligned with the edge of the bed when clamping down before routing or lasering - they can be easily removed after clamping if desired. Hopefully I'll find other uses for them too :-)
The OpenSCAD file is included for customisation. I included variables for the length and fence height (that's the height above the bed, not the total height). I also included a snugness factor variable that can be adjusted to make the finished model fit snuggly in the 20x20mm extruded-section slots.
And if you're interested you can also read my blog-post about this project at the link below.
I printed at 0.2mm layer height, 50% infill, slow speed and thick shells. I don't think it's possible to print properly without supports.
After printing you'll probably need to lightly file or sand the model to make it fit without it being a bit small and wobbly. So it's best to print it very slightly too big so you end up with a nice snug fit.