Mendel design 4 ballscrews

Call me a little crazy, but I know that the mendel can reprint its own parts, however has anyone tried to create a machine that uses a Ballscrew for XY and Z? (yes 4 ball screws 1 x 1 y and 2 z).

Ballscrews give greater accuracy and using some low cost aluminium prefab - mix it with a few ballscrews would make a stronger design and more rigid framework.

Personally I've got a lot of old ITEM aluminium kicking around which is engineered aluminium and would make a stronger system.

Mark.

Unless I completely don't know what a ball screw is, the McWire repstrap uses something similar, except without a ball bearing. The main problem encountered there is that they're too slow, but I'm sure that could change with a different pitch. If I'm not mistaken, the mendel z-axis almost uses ball screws, too.

McWire and WolfStrap, etc use generic threaded rod. If you take a cross-section, it has a triangular or saw-tooth shape. This is optimal for fasteners but not optimal for motion control. We use it for motion control anyway because it is cheap and it works, if not well, and not quickly.

[reprap.org]
uses acme threaded rod. This has a square cross section thread, and is optimized for motion control. You may see it in your inkjet printer, the threaded rod of your garage door closing mechanism, etc.

[en.wikipedia.org]
is a different beast. It has a cross-section like a series of cicular bites. Rather than thread riding in a threaded nut, small ball bearings recirculate between the threaded rod and the inside of the "Nut".
[www.youtube.com]

I've moved this thread to the extruded aluminum forum.

Edited 1 time(s). Last edit at 05/01/2010 03:55AM by SebastienBailard.

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

Real circulating ball screw assemblies are expensive - VERY expensive. Hundreds of dollars apiece.
I'm currently designing a mendel version with a larger print area (12in x 12in x 10in high), using Acme nuts and screws instead of belts. Much less expensive. Still slow, though, compared to the belt drive x and y axes. My current (experimental) x-axis design requires eight times as many turns of the motor for the same amount of movement. But I'm still working on it...

you could get multistart acme screws and it would be much faster moving. a 1/2" 10 turn 5 start would give you two rotations per inch of linear movement

eustace Wrote:
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> Real circulating ball screw assemblies are
> expensive - VERY expensive. Hundreds of dollars
> apiece.

Wow, I guess I've been underpaying for my ballnuts and screws! McMaster-Carr has a 5/8" ballnut for $26.29 (part #
5966K16) and the matching 5/8" ballscrew (5966K26) is $10.22 per foot.

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[haveblue.org]

I'm currently designing a mendel version with a larger print area (12in x 12in x 10in high), using Acme nuts and screws instead of belts.

Eustace, that sounds cool. Where in the wiki are you documenting?

Wow, I guess I've been underpaying for my ballnuts and screws! McMaster-Carr has a 5/8" ballnut for $26.29 (part #
5966K16) and the matching 5/8" ballscrew (5966K26) is $10.22 per foot.

Have Blue, do you know the brandname for the ballnuts and screws? McMaster-Carr won't ship up here to Canada because us Canuks might tranship stuff to the Axis of Evil. (no kidding)

Also, where in the wiki are you documenting?

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

SebastienBailard Wrote:
> Have Blue, do you know the brandname for the
> ballnuts and screws? McMaster-Carr won't ship up
> here to Canada because us Canuks might tranship
> stuff to the Axis of Evil. (no kidding)
>
> Also, where in the wiki are you documenting?

The ballnuts/ballscrews I get from McMaster-Carr are made by Thomson: [www.thomsonbsa.com]
I had no idea McMaster won't ship to Canuckistan - if anyone up yonder needs McMaster goods, drop me a line and I can get them for you.

As for documenting in the wiki, I have something of an aversion to wikis - I always feel like I'm intruding on someone else's space, I have no idea how to properly edit inclusions, and I have no clue as to where such information would best be located. In short, when I look for answers, I search the forums rather than digging through the wiki, and I'm guessing a fair number of others do so as well.

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[haveblue.org]

Does your offer extend to Australia? I'd like to get some of this:
[www.mcmaster.com]

Sure, I can certainly send stuff over to Australia as well. Drop me an email and let me know your McMaster shopping list.

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[haveblue.org]

As for documenting in the wiki, I have something of an aversion to wikis - I always feel like I'm intruding on someone else's space, I have no idea how to properly edit inclusions, and I have no clue as to where such information would best be located.

No worries, you're a RepRap developer and the wiki belongs to you, it's your space:
http://reprap.org/wiki/Rather_Blue_T-Slot_Bot

In short, when I look for answers, I search the forums rather than digging through the wiki, and I'm guessing a fair number of others do so as well.

Forums are great for commentary, feedback, etc. But it's the files and docs in the wiki that keep us going. If you do up a machine strictly as a series of blog posts and forum entries with file attachments, that's well and good, but it's useless to the newbies who wander into the wiki hoping to find actual documentation. I mean, can you imagine Mendel if it were just a series of blog posts and forum entries?

Since you're the lead developer for this sexy new machine ...

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

Hope the name is ok, btw.

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

I hadn't yet figured out a name for the machine, but I'll make sure to post relevant information to the wiki if I actually get to the point of completing the design. I have to finish building the full-size router first, after all...

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[haveblue.org]

That was for the full-size router, actually.

(RepRap doesn't have one yet.)

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!