I felt inspired to create a bubble machine to help entertain my 18 month old granddaughter. (Yeah, that's who it's for. Let's go with that.) Everything prints easily without supports (although you will have to rotate a couple of things to get them oriented correctly). Note that you'll need to print out two bearing rings. One goes on each side of the wheel. In addition to printing out the parts, you'll need six 3/8" ball bearings. You can use a regular household fan to power it or you can print out the fan shroud and mount a dedicated fan. If you decide to use my fan shroud then you'll need to get a 120mm high-speed fan. You're going to want to get one that moves a significant amount of air. A standard computer fan won't cut it. You want a more powerful one like the kind that are used in computer server farms. I used an Axial 1238 server fan which seems to work just fine. The holes in the shroud I made are sized to work with standard 3mm screws so if you have some of those lying around that are long enough, you can use those but I chose to widen the holes a bit so I could use the screws that came with my fan. I've also included a .step file in case you want to mess around with this and remix it yourself. UPDATE: I've added a second bubble wheel that has rings in two different sizes. This seems to give a bit more variety to the bubbles. Give this one a try. I think I like it better than the original wheel.