Projunk's Omniwheel Barrel Casting Form by MirecXP

Last crawled date: 3 years, 1 month ago

I have tried projunk's parametric omniwheels, it is great part for a robot. We have printed its barrels using FlexFill and it worked well on the carpet, but we had some issues using it on the smooth surface.
Now I've tried to cast the barrels from very soft polyurethane (Shore A20) using this mold. I think it will make the wheels more usable even with some other kind of material.
I have no prior experiences to casting, so I'll be glad if you have some proposals for enhancing the mold or the process.
You have to use some 3mm screws to tight the mold parts together. Correct orientation of the assembly has the same text on both sides on the same place. Do not forget to insert the axles in the mold before casting and use some clay to protect the axle bottom holes, otherwise the material may leak. Use the clay also around the edges where the two parts connect.
It is necessary to make all 8 barrels at once using this form, because some liquid material may leak to the empty neighbour barrel cavity. The exact amount of a material to make the 8 barrels is about 17ml, it is enough to prepare 20ml of material. I have used 20ml plastic syringe to fill it. I had to use a small piece of shrinkable tubing at the syringe needle hub to fill the cavities easier. Fill each barrel slowly until some liquid will leak from the small air holes around.
I have not used any removal agent, so it was very hard to open the mold and get the barrels out of it without braking the mold. Good luck. :)
After removal of the barrels it is necessary to cut some excess material with a sharp knife, do not try to rip it off.
Print also the 1-layer washers and put them on the axle on each side of the barrel to prevent unwanted friction between the barrel's sides and the wheel body.