a NEW type of Filament Feeder?? possibly.

Hi,

there's an animation of this proof of principle device I'm working on, which, although not designed or intended to be used on a RepRap, it has been modified a bit to be made on one and should work on them just the same.

The concept, drawings and animations, are covered by a Creative Commons Type2 license and are posted as such on other sites.

This allows for free use, development, discussion on the basis of accreditation, private use and share-a-like, any further developments for specific use with RepRap's will however fall under this sites license.

So basically, for RepRap use it's open source, my other project for which I intend to use it, is not (for now at least).

Also, the Miga Motors are covered by there own patents, but can be purchased and I'm sure an open source, DIY alternative could be devised, (by someone else) so please avoid infringing their rights.

I emailed Adrian to clarify a few points and I believe this is an accurate(ish) appraisal.


Have a look, if there's any interest I can tailor my early prototypes for RR and brake away further downstream, at this point the types of materials I'm pushing, pulling, climbing just need to be variety of stiffness and of small diameter.

Miga Motor Specs are on their site...

For starters, if someone local to London has some filament off-cuts to play with...


[gallery.me.com]

cheers

john

Hi John,

I'm afraid this won't really be suitable, because you cannot continuously feed at a fixed rate. Also, I don't see how this is any simpler than the current pinch-wheel design which is in production use. Additionally, there is a huge gap between concept and practice...

-Geert

Hi Geert,

I realise this is deferentially one for the the developers out there.

Although the motors themselves are fully compliant commercial products used in auto, medical and aerospace industries the idea of applying them to a hollow linear motion device is what appears to be new and what I'm investigating.

The model is quite crude because my cad skills are rather lacking and I wanted to keep it as simple as I could.

My intention is in fact to cascade at least a two sets, and ripple the feed so that one pair is always pushing at a constance force of up to 22 N at a speed of up 50ms to get up to 200 mm/sec. running them very slowly to achieve 4-5 mm/sec to feed 3mm rods simply uses even less power and greatly extends their lifespan.

there are much smaller boards that will work for these speeds ,but I have this size for my needs.

With feedback they become fully position-able at, full torque, in both directions

As this is well over-specced for the current line of RepRap (from 4 off the shelf motors weighing 13 grams each) made me think it could be a way forward for the high speed, multi head devices that some people are dreaming of.

In the short term, they would be far more expensive then all the current solutions but could avoid any twisting and work on soft solder or ABS equally as well.

Thanks for your comments, I'll end up doing a full breakdown eventually, but I wanted uninformed comment as well.

Oh, they can also run off the same current control board at the same or lesser or greater voltages.

john

I like it.
I've seen these devices before sold on sparkfun.com in the US.

Because they have a high degree of precision and instantaneous torque, I think they might be very useful for pulsed extrusion, where the amount of plastic extrudes is carefully controlled by rapidly pulsing the feeder. Look up how ink jet printers push ink out of nozzles for an idea of how useful this would be. I'm not sure if this motor and filament feeder fit the profile, but it looks like it is on the right track.

Keep up the good work,
Lawrence

John,

Opinions are cheap. Build it and test it. That's the only way to know if it will be any good or not.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

:-)

I'm afraid you'll get a lot more support if you have a go, than posting ideas. Most of us have our own ideas we're busy with, testing out, and trying to get working - there's very little time left for real life, let alone anything else.

Posting any idea, you'll get positive and negative comments. Truth is, no-one really knows - we can have a guess, maybe point out some obvious problem areas, but the only way is to build a prototype and have a go.

Some of the most counter-intuitive ideas work fine, and some of the obvious ones just don't work. Extruders and drive systems is such a complex area, with so many inter-related variables, it's really difficult to tell!

Good luck, and let us know how you get on!

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Reprapping blog and other rants: [renoirsrants.blogspot.com]
My Reprap: [sites.google.com]

Hi John,

some years ago i developed a flat oszillating drive with form-/friction-mechanism what would work in a similar way but is maybe simpler to fabricate.

Look at the dokuments and drawings here: [depatisnet.dpma.de]

When arranging two (or more for smoother moving) machanical oszillators around the filament with a fitting surface covered with small slope blades or fibres (as showed in the drawings) then you'll have a drive with defined feed per osz-step and very high torque ...

Viktor

Edited 1 time(s). Last edit at 06/17/2009 03:30AM by Viktor.

... for a thought of the 'flat oszillating drive'-function you can look at the photos regarding "OSZ-Gleiter..." here: [www.ctbot.de]

I built some moving demonstrators with Fischertechnik and a sort of 'slant-fibres-tape' and some rotating drives and elevating mechanics too.

Imagine the same structures much smaller not on a plane but in two half-pipes surrounding the filament and you have a filament-feeder which can apply as much force/torque, as the fibres can withstand - i calculated for perfect aligned carbon nanotubes against a hard smooth surface some ten thousand(!) Newtons, but the only material that can handle this forces would be pure diamond

Viktor