I recently got into printing robot parts, but hit a snag when it came to finding mecanum wheels that could be created with almost nothing but printed parts. I looked online and found CAD files for 8 inch mecanum wheels from AndyMark, which I rescaled to ~3 inches and printed each part from there. I included the Autodesk Inventor assembly file in case you want to rescale it from there, use it in your own CAD modelling etc. My rescaled .stl's are just the right size to mount a servo horn onto, making it perfect for servo-driven robots.
Here's the site I found the CAD drawings from - http://www.andymark.com/Mecanum-s/53.htm
For 1 wheel of 1 type:
- 4-8 spacers, depending what rigidity you want
- 2 mech plates (left or right), with full support
- 12 rollers
For a full set:
- 16-32 spacers, depending what regidity you want
- 4 of each mech plates, with full support
- 48 rollers
You will need at minimum, 8 #2x8mm screws per wheel to attach the plates. You can hot glue them if you wish, but screws will be the strongest option. These are the screws I used - http://www.amazon.com/dp/B000NHXO1M/ref=biss_dp_t_asn
I printed 12 rollers at a time and peeled them off the raft and sanded them down to make them smooth. To attach the rollers to the plates, I used 1.75mm ABS rivets (instructions here - http://www.youtube.com/watch?v=WqNxYHWpYko)
When you print out the plates, print them with full support. Because there are 45ÃÂº bent "petals", the plate part itself is off the print tray. It will take quite a bit of work to clear away the support material, but it is worth it.
You can mount these wheels to anything, but I chose servos. The larger holes are the perfect size for a servo horn, which you can even mount a horn when you screw in the spacers.
When you attach the rollers to the plates, make sure you leave at least a milimeter of space between the roller face and the "petal" face for smooth rolling.
EDIT - I updated the screw size for the 3 inch wheels, they need to be #2 screws. They can be found on Amazon for $3 for 100.