Saturday, December 05, 2009

Can we print belts?



Yes, if we step back and look at what a belt does instead of simply trying to replicate existing ones.

Belt driven Reprap machines have always bothered me. They're fast and now that the price of NEMA steppers is getting reasonable, they're even becoming economical. It bothers me, however, that the belts and sprockets can't be printed very easily.

Last night I was cleaning up a corner block that I'd printed and was cleaning out a bearing seat with my Dremel tool fitted with a cylindrical abrasive head. These are a nice little fitting that lets you slip what is a cylindrical piece of sandpaper onto your Dremel. They are cheap and very effective.



I was looking at it when I realised that the toothed belts are toothed to prevent slippage and that there are other ways to prevent slippage than teeth.  An abrasive cylinder, for instance.  With an abrasive sprocket you wouldn't need teeth and the belt wouldn't need teeth either.

It was a matter of a few moments to design a 600 belt in Art of Illusion that would easily fit on my Rapman print stage.




A few minutes more and I had it run through Skeinforge and printed it in HDPE.





Cleaning the belt took a few minutes, not no big deal.




The resulting belt is very flexible and quite strong.




I've got a pile of NEMA 17s.  I might just print myself out a Mendel now.  Mind, I will be using my OWN electronics.

8 comments:

mccoyn said...

If you print a spiral belt you will avoid any tight turns and have all the turns going the same direction. That should make your belt more consistent.

Wade said...

Nice! Printing a looped belt would save a lot of trouble splicing belts for the Z axis.

The other advantage of teeth is that they correct slippage, up to a point. Without teeth you'll need to zero your axis a lot more often, depending on how much slippage you get.

Nothing stopping you from printing toothed belts too though.

Guy said...

You could mount 2 heated metal gears a little closer together than the belt thickness to make a toothing device.

Forrest Higgs said...

Nice idea.

Corwin said...

Why not print it with vertically aligned gaps? In other words, if you look at it from the side (the widest view), you would go from seeing something like
|||||||||||||||||||
|||||||||||||||||||
to something like
||**||**||**||**||**||
||..||..||..||..||..||
and effectively produce something between a toothed belt and a chain?

oiaohm said...

There are people mucking around with removable filler material.

Toothing is one option. Ladder belts is another.

So far I have seen no one experiment with making chain. Really one way chain is better than belts. Ie defective parts of chain can be replaced.

Joel said...

Wow, cool!

And it wouldn't be too difficult to close the loop from the get-go, either.

Print slowly enough, and it can all be one continuous extrusion.

Prober said...

Why not print it with vertically aligned gaps? In other words, if you look at it from the side (the widest view), you would go from seeing something like
|||||||||||||||||||
|||||||||||||||||||
to something like
||**||**||**||**||**||
||..||..||..||..||..||
and effectively produce something between a toothed belt and a chain?

Like the idea...how about building the position sensor into the belt?