How about air bearings made of plastic?

Still working on my first own printer I'm wondering, if it shouldn't be possible to print bearings working with compressed air.

While the surface quality of the inner side of the bearing is less important, compared to metal-bearings, it should be possible to e.g. drill the inner part to the correct diameter.

I'm thinking about that because of the LM8UU-bearings, which are either expensive or lousy in quality.

Compressed air bearings are not that new (common for precision machines), but I wonder if they, for our purposes, could be printed.

Here's a short video about the technology: [www.youtube.com]

It's possible, but I do we have any need for the capabilities such as high speed / high load bearing that fluid bearings offer? It would add more complexity and vitamin count for what benefit?

Still I would like to see it done. It should be very easy to design and mock up, though I don't have an air compressor at the moment to power it... hmm.

Nyarlathotep Wrote:
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> It's possible, but I do we have any need for the
> capabilities such as high speed / high load
> bearing that fluid bearings offer? It would add
> more complexity and vitamin count for what
> benefit?
I try to reduce the vitamn count, not to raise it. The (printed) compressor raises the vitamin count would allow to replace the bearings and, more important, reduce the runtime costs that abrasion would cause over time. That's the idea.

>
> Still I would like to see it done. It should be
> very easy to design and mock up, though I don't
> have an air compressor at the moment to power
> it... hmm.
I'm thinking of a small printed compressor. Souldn't be too complicated.

Uh, then you have this compressor running all the time. Might be a quite noisy experience. Also it's probably a challenge on its own to design a printed compressor which survives more than a few hours.

What's wrong with simple, plain old bushings? The better ones from IGUS or even printed ones? Especially with printed ones I see quite some room for improvements over the current technology.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Traumflug Wrote:
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> Uh, then you have this compressor running all the
> time. Might be a quite noisy experience. Also it's
> probably a challenge on its own to design a
> printed compressor which survives more than a few
> hours.
Maybe. It's a challenge, of course. Wouldn't be interesting otherwhise.
It's a question of how much pressure is needed. Think about compressors for aquariums. They are very silent and quite simple constructions - not so powerful though.
On the other hand a wobble-compressor (which is silent too) with one or two pistons and blade valves can be printed quite easily and would be relatively powerful.
I've got an old two piston wobble-compressor here that can serve as a master.

> What's wrong with simple, plain old bushings? The
> better ones from IGUS or even printed ones?
> Especially with printed ones I see quite some room
> for improvements over the current technology.
There's not too much wrong about classic bearings, especially if they are printed. But abrasion is an issue, even for good bearings, while air bearings don't wear out.

RobertKuhlmann Wrote:
-------------------------------------------------------
> Nyarlathotep Wrote:
> --------------------------------------------------
> -----
> > It's possible, but I do we have any need for
> the
> > capabilities such as high speed / high load
> > bearing that fluid bearings offer? It would add
> > more complexity and vitamin count for what
> > benefit?
> I try to reduce the vitamn count, not to raise it.
> The (printed) compressor raises the vitamin count
> would allow to replace the bearings and, more
> important, reduce the runtime costs that abrasion
> would cause over time. That's the idea.
>
> >
> > Still I would like to see it done. It should be
> > very easy to design and mock up, though I don't
> > have an air compressor at the moment to power
> > it... hmm.
> I'm thinking of a small printed compressor.
> Souldn't be too complicated.


A printed bushing doesn't require any vitamins, though. They will eventually wear out but with a well-tuned machine a printed PLA bushing can certainly run for some months of heavy use. I think Nylon would make a better bearing material, but I'm not certain if the Nylon formulations we have available for printing is optimized for wear or not.

I have tried nylon (taulman 618) as bushing material. I think it is safe to assume that it will last a rather long time: My test setup

If bushings wear out, they have to be made adjustable

@RobertKuhlmann: you're right, it depends on pressure and volume required. Have you any idea how much this would be?

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Generation 7 Electronics	Teacup Firmware	RepRap DIY