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Reprap Rack and Pinion axis drive system

by cyborg527 Dec 12, 2011
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I used a similar concept in my new printer. Your part here was what made me think about using this type of mechanism, but I ended up using a different thing as the part. My printer is on: http://www.thingiverse.com/thing:15611http://www.thingiverse.com/thi... It does work ok...

Alu reprap
by larsie

That was exactly what I was hoping someone would do.

Glad to hear! :-D

Oh btw, before I forget it. I tossed up a thread on RepRaps-forum regarding "this": http://forums.reprap.org/read.php?184,109884,109884#msg-109884http://forums.reprap.org/read....

Hopefully some nice information pops up there sooner or later! I'll keep it ajour of my findings as well. Keep up the good work!

inn the y direction what if the linear ballbearings where connected to the frame and the rails where connected to the print board instead of the frame. maybe it would be possible to make prints in the Y directions longer than the frame itself. It would wurk great together with the rack and pinion system

my hopes are that you could scale up future repraps by adding more of these modules to a chain

I'm sorry, but I have to...

That's a rack and pinion gear system, not a belt, but that doesn't stop it from looking like this could really work.

If a monkey took the place of a bicycle wheel, it's still a monkey.

would you be happier if I renamed it the rack and pinion system for repraps? DONT_KNOW

It would be taking the place of a belt in this case though.

this is brilliant. the timings belts are one of the more expensive parts of the reprap, so being able to print them would be amazing!

No they aren't. A pair of timing belts costs about $12. Contrast that to five motors at $16-20 apiece and the electronics that run between $100 and $200.

I think he means one of the most expensive non-electronic parts.

They're nowhere near the most expensive non-electronic parts, either. Those smooth rods ain't cheap, unless you get crap ones.

The idea isnt a bad one! but needs a little more work..

The linear "belt" is commonly used in the industry but looks a lot different. Check out


The "teeath" have special form to ensure a smoth run...

the thing with the teeth is I don't think 3d printers have a high enough resolution for those measurements to matter yet. the couple belt stick prototypes I printed out fit really well with the gear I put in the description.

I wonder if you could get higher resolution using a worm-gear instead of a traditional one with this build? -- I.e. stationary worm gear, with the rack mounted on the moving axis.

Also it would be good if you could add side rails to keep the gear from popping off the tracks on either side making it more rigid on the perpendicular axis.

It would be very neat if we could eliminate all of the non-printed (non-electrical) hardware on the rep rap (i.e. snap together plastic f
rame that doesn't need threaded rods...)

And I know the maker bot has the "heated conveyor belt" thing -- it would be cool to duplicate that with a hinged build area that 90% of the time was completely flat and rigid, but could be "pushed off the edge" so that it flopped down or something and the p
rinted parts fell off into a padded box or bucket...

Im making rails, and I have plans for motor mounts, I also have been toying with the idea of a worm gear. that's what the makerbot uses in its z axis, and it seems to work very well.

Im sure this is well within your relevant interestszone: http://www.thingiverse.com/thing:8938http://www.thingiverse.com/thi...

Linear Rail Gantry system V2

I don't quite understand. Is this meant to be flexible? It reminds me more of a rack, as in rack and pinion. If you want it to fit a timing pulley, you can Google the specks for the belt and get a dimensioned drawing.

I just learned about racks and pinions and yeah thats pretty much what it is, or kind of like a rigid belt to push or pull an axis carriage

I had a similar moment years ago when I "discovered" the drive ability of the common screw only to find out it had been a well known use of screw for several hundred years at least - don't be discouraged as some of the most amazing inventions have simply been from new fresh eyes reexamining the standard solutions to known problems - just because something has always been done some way most definitely does not mean that thats the best way to do it.

I actually kind of like the extension to this idea where you might print the rack on both sides of the stick and then attach the rack to your device. One of the things that keeps automation complexity (and costs) high is that we still for the most part use one set of "things" for controlling the
linear motion itself and another for controlling the location - e.g. most systems have rails of some sort for one and a screw, belt, rack, etc for the other. If we can figure out simple ways to combine them it will reduce both complexity and cost. Having the stick ride on a fixed set of gears and
bearing that control both location and linearity might be an idea in that direction.

lookup convergent evolution. what happened here was I rediscovered something that had already been made. I don't consider it a another invention, all I did was think about a belt that was cut at one end, and that was rigid, and it turned out to be a rack and pinion.

This guy just invented the rack and pinion drive system again. Nobody told him it existed, so he came up with an idea that would work better than belt drives. That's pretty impressive, really.

instead of an actual belt that wraps all the way around, this is more of a sliding stick that attaches to the x and y axises it sticks out either side instead of wrapping around the two pulleys on either side.