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Mendel design 4 ballscrews

Posted by Mark Bauer 
Mendel design 4 ballscrews
April 30, 2010 05:32PM
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.
Re: Mendel design 4 ballscrews
April 30, 2010 08:17PM
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.
Re: Mendel design 4 ballscrews
April 30, 2010 11:43PM
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. grinning smiley

Edited 1 time(s). Last edit at 05/01/2010 12:55AM by SebastienBailard.

-Sebastien, RepRap.org library gnome.

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! grinning smiley
Re: Mendel design 4 ballscrews
May 01, 2010 10:56AM
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...
Re: Mendel design 4 ballscrews
May 23, 2010 10:25AM
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
Re: Mendel design 4 ballscrews
July 02, 2010 03:02PM
eustace Wrote:
-------------------------------------------------------
> 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.


[haveblue.org]
Re: Mendel design 4 ballscrews
July 26, 2010 10:07PM
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? smiling bouncing smiley

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) smoking smiley

Also, where in the wiki are you documenting?


-Sebastien, RepRap.org library gnome.

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! grinning smiley
Re: Mendel design 4 ballscrews
November 30, 2010 07:56AM
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) smoking smiley
>
> 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.


[haveblue.org]
Re: Mendel design 4 ballscrews
November 30, 2010 05:40PM
Does your offer extend to Australia? I'd like to get some of this:
[www.mcmaster.com]
Re: Mendel design 4 ballscrews
November 30, 2010 06:25PM
Sure, I can certainly send stuff over to Australia as well. Drop me an email and let me know your McMaster shopping list.


[haveblue.org]
Re: Mendel design 4 ballscrews
November 30, 2010 09:34PM
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 smiling bouncing smiley

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? smileys with beer

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


-Sebastien, RepRap.org library gnome.

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! grinning smiley
Re: Mendel design 4 ballscrews
November 30, 2010 09:58PM
Hope the name is ok, btw. grinning smiley


-Sebastien, RepRap.org library gnome.

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! grinning smiley
Re: Mendel design 4 ballscrews
December 01, 2010 07:17AM
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...


[haveblue.org]
Re: Mendel design 4 ballscrews
December 02, 2010 07:43AM
That was for the full-size router, actually.smiling bouncing smiley

(RepRap doesn't have one yet.)


-Sebastien, RepRap.org library gnome.

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! grinning smiley
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