"Brutis" Breeder Mini Mendel redesign

My wife has took to calling it Brutis, because what I have together so far looks so beefy

A few design questions, I didn't know if anyone had a good answer.

-On the Mendel, the thinest part that holds a NEMA 17 is the X solid end bracket, and it's 5mm. Other parts are in thicker brackets, and have side supports. I take that to mean that the minimum a nema 17 should have would be the 5mm/no side supports. That's what I am designing to. Is that a bad assumption?

-On a bowden extruder, the extruder is usually mounted below the build plate, but I am considering mounting my extruder mirrored to the X axis motor, with the ptfe tube fed up and back down onto the trolley and an acyric tube fed down to my printed filament spool. Is there a reason for the normal bowden positioning?

-Does anyone know a cheaper place to get PFTE tubing int he US than Mcmaster carr? $5 a foot is steep.

If you have any sugjestions please post it here or over at [reprap.org] I will post the parts to Thingiverse because I don't know how to upload them to RepRap.

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repraplogphase.blogspot.com

If you have any suggestions please post it here or over at [reprap.org] I will post the parts to Thingiverse because I don't know how to upload them to RepRap.

That's not good. (Also, there's a bit of politics there, I'm afraid ).

I've added this to the text of the wiki page:

=Files on the RepRap wiki=
*[[File:all_the_brutis_parts.zip]]
*[[File:all_the_brutis_parts.tar.gz]]

If you now go to
http://reprap.org/wiki/RepRap_Breeder
and click "all_the_brutis_parts.zip" it will prompt you to upload the file. Or you can use the command on the mediawiki page "upload file" (lower left, under 'toolbox') but it's less elegant.

Please email me if you have any trouble at all with any of this.

Also, you may want to cut-and-paste example layout stuff from
http://reprap.org/wiki/Example

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If you want to change the name to
http://reprap.org/wiki/Brutis
http://reprap.org/wiki/Behemoth
http://reprap.org/wiki/Hooke
http://reprap.org/wiki/Pookey
add #REDIRECT [[pagename]] to the old page.

I'm bad with names.

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Does anyone know a cheaper place to get PFTE tubing int he US than Mcmaster carr? $5 a foot is steep.
Did you try ebay?

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Are there any php developers out there who want to help RepRap?
Help us develop Big_Fat_Upload_Button technology.

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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:
-------------------------------------------------------
> Are there any php developers out there who want to
> help RepRap?
> Help us develop Big_Fat_Upload_Button technology.
>

I like this. Thingiverse isn't a good base for extensive documentation.

and

"-On a bowden extruder, the extruder is usually mounted below the build plate, but I am considering mounting my extruder mirrored to the X axis motor, with the ptfe tube fed up and back down onto the trolley and an acyric tube fed down to my printed filament spool. Is there a reason for the normal bowden positioning?"

I am pretty sure it is mostly to eliminate sharp bends.

Edited 1 time(s). Last edit at 07/25/2010 12:22AM by tesla893.

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-Steve

The main reason I am looking to put the extruder on the X axis (but not on the trolley), is so that I can use less PTFE. If the tube is only moving back and forth with the trolley, not back and forth and up and down I should be able to shave 1 foot off it's length, which in a project where I want to have a Pololu Electronics option that allows for $300 printers, every $5 counts

Now I have to print out some of these parts, and order my PTFE tube. I have everything else in shipping or on my desk.

The 1st build will be a RepG/Makerbot/ATX power supply version so that it is as easy as possible to set up as possible electrically (for me).

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repraplogphase.blogspot.com

I've found ptfe tubing on ebay before, pound or two per metre, in ~3m lengths. My bowden extruder isn't finished yet, but you really do want to reduce bending as much as possible, so this probably isn't the best place to cut corners. The tube I have barely stretches, but as you bend it it shortens a little, so I'm going to go for a fairly big loop. Microstepping the extruder motor helps as well, because the extra spring due to the tube makes it more likely to skip steps.

So... What if I where to mount the extruder above the x trolley? Say like this [www.thingiverse.com] .

The tube would be almost perfectly straight for the 1st few layers, and the higher you go the more bend that would occur. Mini Mendel is already pretty restricted on the Z axis anyway, so shouldn't be hard to mount the extruder 300-400mm above the top of the machine. Is this worth trying? Every foot adds cost, and I want this to be as cheap as possible.

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repraplogphase.blogspot.com

spacexula Wrote:
-------------------------------------------------------
> So... What if I where to mount the extruder above
> the x trolley? Say like this
> [www.thingiverse.com] .
>
> The tube would be almost perfectly straight for
> the 1st few layers, and the higher you go the more
> bend that would occur. Mini Mendel is already
> pretty restricted on the Z axis anyway, so
> shouldn't be hard to mount the extruder 300-400mm
> above the top of the machine. Is this worth
> trying? Every foot adds cost, and I want this to
> be as cheap as possible.


I would say test and try... But my mental experiments with bowden driver positioning tend to lead to the conclusion that Ed put it in the right spot. Think of it as bike braking cables... They are convex relative to the brake lever and the frame like this....[www.abikestore.com]

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-Steve

[www1.mscdirect.com]

Will this work for bowden cable?

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-Steve

No, but this one would. (you need 1/8 inch ID)

[www1.mscdirect.com]

Wow, good catch. That's 1/2 the price of Mcmaster carr, and they have more varitety.

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repraplogphase.blogspot.com

What McMaster-Carr tubing are you talking about? Do you have part numbers?

As I was discussing here, McMaster PTFE tubing is very cheap.

Brand-name Teflon:
5239K11 ($1.09 per foot)

Semi-transparent PTFE with colour bands:
53935K221
53935K222
53935K223
53935K224
53935K225
($1.25/foot)

Those are all 1/32 inch thickness walls. you need at least 1/16 inch so that your cable is rigid. The cheapest Mcmaster carr sells is 52365K615, which is $3.23 a foot. MSC is $2.89 a foot. It's not huge, but I am trying to get the cost down, and ever few dollars helps.

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repraplogphase.blogspot.com

Really? I thought a rigid cable would be worse, because it needs to flex as the extruder moves around, and a rigid cable would introduce drag on the print head (especially with a multi-head system). Has anyone tested it?

All bowden to date to my knowledge have had 1/16 inch walls. You want the ridged wall because it reduces flex due to the extruder.

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repraplogphase.blogspot.com

With too thin of a wall it will fold onto itself.

MSC is a good place to order stuff. I honestly forgot about them until my dad reminded me today.

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-Steve

I think Vik mentioned this in IRC a few days ago, but polyethelene tubing for ice machines seems to be decently low friction. I bought three feet at Lowes today for $.16/foot. I can easily push filament through the whole length. It is 1/4" OD.

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-Steve

Thanks for the heads up

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repraplogphase.blogspot.com

Wow, if I go with Bushings instead of bearings, I will be able to knock 20 dollars off the cost, reduce the rp parts by 1/3 (some were between 20-25 peices TOTAL), and add 10mm to the Z axis. I think I am going to have to move to bushings... bye bye 70% of the work I have done to date

What brought this on was prusajr's photo of his/her X axis. beautiful! (and several people on the RepRap forum that pointed me in the same direction)

[www.flickr.com]

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repraplogphase.blogspot.com

spacexula Wrote:
-------------------------------------------------------
> Thanks for the heads up

[www.youtube.com]

Didn't workout so well...

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-Steve

New Brutis development page

Brutstruder design page

The Development page has a quick update. Hope you enjoy it.

Yea Tesla has took over the design of the Brutis, I am working more on trying to get a functional Mendel Farm operational right now. He seems to be doing a good job so far.

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repraplogphase.blogspot.com

I just added a forum-widgit-rss-fee link from the brutis wiki page back to here.

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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!

Of late I’ve broken down the Brutis into two groups
1) Orphaned (Alpha) Brutis designed in Heeks Cad
2) Brutis Mini-Mendel based on the Prusa Mendel
[reprap.org]

A test release of the x carriage for prints on a MakerBot has been released
[www.thingiverse.com]