Beads rather than belts?

I gather that the toothed belts are expensive. I grabbed 14 feet of Christmas bead garland at the dollar (plus tax) store. The beads are 8mm in diameter, and are spaced 2.3mm apart. That's big enough that the gear which drives them could be fabbed. In the meantime, we could use a technique like Vik's to create a gear.

The cord that holds the beads is quite inelastic. Over a 15cm section, a 5kg load only stretches it by 1mm.

Hi Russ,

... look for ready made beaded wires as used in window-rollos.

The connecting to a loop can be made with cast-molding the two ends with a molded bead ...

Viktor

I have a lot of this stuff sitting around--maybe 40 feet--and only have one issue with using this as a belt. How to connect it into a continuous loop. The only problem I'm seeing is that any connection joint essentially fuses two beads together causing the gearing portion of the system to choke on it. Basically it requires that each bead be seperate while any fusing system actually attaches the two beads together into a longer "tube-like" styructure that is no longer round and will not fit in the indentation for it in the gear system. Fix that and I'm a happy camper with this method.

Demented

Hi Demented,

... in an older post about the same problem (some months befor) i described one possible workaround:

- mill two halfs from aluminium with 3 (or more if for self-manufacturing beaded strings) halfspheric cavities in the size and distance of the beads ...
- draw over the complete length a centric v-grove for the string ...
- drill in one half holes to the cavities for injection-molding ...

Then insert the two end-beads in the outer cavities, connect the string with a small knot in the inner cavity (or only overcross the string, so the ends are out of the cavity), close the aluminium-mould and press hot plastic in the hole so you fill the cavity complete ...

Viktor

I thought all this looked familiar. There was some discussion about bead chains on the main blog: [blog.reprap.org]

It also just occurred to me that you can make your own using beads and monofilament: [jewelrymaking.allinfoabout.com]

Using cylindrical beads in an H pattern, you could even do a fairly decent sprocket chain. Something like this: [www.beadfx.com] ...only less ornate.

Edited 1 time(s). Last edit at 12/18/2007 03:25PM by Steve DeGroof.

Viktor,

Not totally understanding what you are saying. I think I get it but a picture would help!

Demented

Hi Demented,

... here a sketch:



Viktor

Edited 1 time(s). Last edit at 12/19/2007 01:43AM by Viktor Dirks.

Ah, I see. Very clever. That'll work just fine. The only problem remaining then is mold creation and the durability of the final product. Have to do some real-world testing to discover those.

Demented

... found an old 'comercial' beaded (+toothed) belt, what could be interesting even today too

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

wow Viktor, that's a... more than 7 years old follow up!
you're quite a believer :-)


At that time, 2007, probably toothed belts were quite expensive.
Now....the price equals to a roll of good filament.

I thing that, although various other solutions might work, a toothed belt is already a standard solution with good results and the price is not an issue any more.
In the end, a 3D printer is not a ... 2$ hobby....

Quote
alexella
wow Viktor, that's a... more than 7 years old follow up!
you're quite a believer :-)

... sometimes - uhmm - yes ... but 7 years aren't really long -- this part in the image, I've found in my basement, is around 25 years old and I've done my first DIY-3D-fabbing and related development around 1990 too ... and now working in this sector again

For the actual status of the 'timing' (or 'posidrive') belts here some links I've got in another CNC-forum:

[sdp-si.com]

[www.pic-design.com]

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]