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View Full Version : pic: Poor Man's Omni Wheel

Sean Schuff
24-01-2006, 15:06
[cdm-description=photo]22579[/cdm-description]
phrontist
24-01-2006, 15:06
Since when does CNC qualify as "minimal machining"? ;)
Chriszuma
24-01-2006, 15:16
You see, it's all relative. It's "poor man" compared to some other omni wheels, while it's "Sultan of Umbapamawow" to people not involved with FIRST
Sean Schuff
24-01-2006, 15:39
Since when does CNC qualify as "minimal machining"? ;)

You could get away with a simple mill and indexing head. We happen to be a PLTW school and have the ProLight mini CNC Mill. Yes, "minimal" is relative - but it isn't a $60,000 CNC mill.

Yee Haa!

Sean
ChuckDickerson
24-01-2006, 15:42
Nice job! That looks like something even our little team could tackle! I really love to see this kind of resourcefulness in FIRST. I think an off season white paper is in order! I would love to see how you made them using COTS parts and how the hold up during competition. Best of luck! I love 'em!
tbmantia
24-01-2006, 15:51
http://omniwheel.com/transwheel/transwheel-4000.htm

Might not be as big, but they are very cheap and won't take any time. We have used them for years and they work great.
KenWittlief
24-01-2006, 16:30
What material is used on the white rollers? It looks like nylon. Are you planning to cover the rollers with some friction material?

Ideally they would have excellent friction (grip) in the wheel rotation direction, and roll freely sidesways.
Astronouth7303
24-01-2006, 16:55
I don't think omniwheels count as "simple"...
Kyle Love
24-01-2006, 17:14
poor man omnis? Those things are amazing looking!
Sean Schuff
24-01-2006, 18:45
What material is used on the white rollers? It looks like nylon. Are you planning to cover the rollers with some friction material?

Ideally they would have excellent friction (grip) in the wheel rotation direction, and roll freely sidesways.

Actually tbmantia's link (http://omniwheel.com/transwheel/transwheel-4000.htm) has the exact same rollers we are using. They are the synthetic rubber coated polypropylene roller. Excellent rigidity at the core with a very "grippy" surface. We have yet to test them to their full limit but are confident they will work out well even if they need to be swapped out periodically. Ease of maintenance and low cost make replacing them as they wear a relative non-issue.

One of the other positive characteristics of the barrel rollers is their football shape. This makes rolling a lot less bumpy and makes for more solid contact on and between rollers.

One other spec I failed to mention - they are 6" diameter wheels to the outside of the barrel rollers.

Stop by our pits in Cleveland, Milwaukee and/or Atlanta to see them up close and get a status report on their effectiveness.

Sean
Rickertsen2
24-01-2006, 20:24
We have 2 of those mini CNC mills. I always saw them unfit for anything but making keychains and circuit boards. I never considered making plastic parts. Good idea!!
Jeff Pahl
24-01-2006, 22:48
We have 2 of those mini CNC mills. I always saw them unfit for anything but making keychains and circuit boards. I never considered making plastic parts. Good idea!!

We regularly cut 6061 aluminum with our mini CNC mills. Both are Sherline mills modified for educational use (one is a Denford, the other is a Intellitek spectraLIGHT). The trick is to know what the machine limits are, and to use sharp, high quality carbide tooling. Last Saturday I used one to drill the bolt circle patterns for the sprockets on the sides of the timing belt pulleys for our treads.

When they're the only machine shop you have, it's amazing what you will figure out to use them for :)