Omniwheel

This is an omniwheel I use on a threewheeled omnidirectional robot. The wheel is as simple as I could think of. It is a lot of work to print and assemble three of them, and you would probably be better of buying them ;-)

Still, I had a lot of fun printing them, and if you want to make this model too, here are some pointers from my experience with making them.
 

Plates
I printed the plates with a 0.4 nozzle and a layer height of 0.2 (using the “0.2mm QUALITY” preset). There is no support needed to print them.

Rollers
I used TPU PLA to print the rollers. This is actually the hardest part of the model. The TPU is very stringy and I ended up printing them one by one because of that.
I used a nozzle of 0.4mm and layer height of 0.2mm and for infill I choose 80% concentric infill. This gave a reasonable hardness while still keeping some of the flexibility of the TPU.

Roller Sleeves
I first tried to print the rollers without the sleeve but because the TPU is not printing as smooth a standard PLA the rollers would not turn smoothly on the axis. So I decided to print PLA sleeves to insert into the rollers. 

The sleeves are printed with a 0.25mm nozzle and a layer height of 0.10mm. The slicer will report printing instability, but I had no problem printing them without a brim. As long as you make sure you use the smooth build plate and have it cleaned with alcohol, it will work out.

Separator
Very easy part, nothing special to mention, used a 0.4mm nozzle and 0.2mm layer height

Assembly
The sleeves fit snuggly into the rollers, I pressed them partly in by hand and then used a small hammer to get them fully in. They are designed to protrude a little bit.

For the axes, I used 2mm steel rod that I cut in pieces of about 23mm

The outer- and inner plates are fixed together with small m2 screws and hold the axes of the rollers.

The assembled plates are separated with the separator part. As hub I used a Pololu 3mm hub. 

The plates, the separator and hub are then fixed together with four m3 screws of 20mm length.