Readers: If you want to build the power expander featured in this post, please go to PCBWAY's Community pages--a gerber ready to download and/or fabricate as well as KiCAD files, stl for 3D printing, FreeCAD files, and so on are here.
Also please visit PCBWAY's site using the link here--it will help this blog. Thanks.
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I had so much fun getting started Kicad, why stop there? I needed to replace Fusion 360 whose license fee will go up by >700% in a few years with something more affordable.
After some looking around I chose FreeCad, a popular open source choice for 3D modeling.
As a first project I created a tray for an improved Warm Floater (initial post here). The Warm Floater is a small PCB allowing 3 Euro modules to be powered by a single 16 conductor ribbon.
The update employs box headers in an effort to make it nearly impossible to orient the power cables incorrectly.
FreeCad seemed difficult to grasp at times but after a few evenings I got it working. There are endless youtube tutorial videos about it that got me me out of most jams.
And I need to remember: it's free. No whining!
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| 3D printed tray printed by my patient sponsor, PCBWAY |
Like Fusion360, Freecad starts with 2D sketches and allows you to extrude them (FreeCad calls this "pad") to a 3D shape.
A few of the issues I had with FreeCad:
I was unfamiliar with "constraining" my sketches, locking down proportions. A good video about sketch constraints is here. This makes sense, we don't want our dimensions drifting all over, but at times the sketch looked constrained to me but I still got at least one "DOF" ("degree of freedom") and found I was "under constrained" (since I married my psychiatrist girlfriend, no, but in the world FreeCad, perhaps?)
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| Doh!! still one DoF! |
I couldn't figure this one--I could tug and pull and my sketch would stay put, so what was underconstrained? but--my tray still printed OK.
Everything with different Z extrusions had to be its own sketch. Maybe. Still trying to figure that one out.
To make the tray edges for this post's project I had to craft a rectangle sketch on the XY plane, extrude or "pad" it, then "pocket" it, making the tray's Z access edges. So far, so good.
Next I created a second sketch and constrained two 3mm holes. The second sketch was superimposed on the first. Then I could "pocket" the holes (sketch 2) to push them though the tray (Sketch 1). I could find no other way to do this, and this seemed like a lot of steps to create an extremely simple 3D shape.
Again, once I figured it out it made sense, but I kept trying to get the holes cut out of the tray within the same sketch--nope.
I printed one of these out on my 3D printer but needed more of them.
With my tray STL file in hand, I whipped up a simple PCB uploaded both to PCBWAY, yes they do 3D printing, and wham, it was back. The 3D print jobs looked great. I am not saying that because they're my sponsor, really, the quality of the print was top notch.
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| 3mm nylon screws and nuts fastens the PCB to the tray |
This got mounted in my bench rack, now I can put more modules with low current draw in there....much needed improvement.
I figure I will get better at Freecad over time....this still feels very new to me.
See ya next time.
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