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Support material header

Posted by Assargadon 
Support material header
August 31, 2007 12:25AM
Does it planned to include support material header in Darwin?
Or in Mendel only?
Re: Support material header
August 31, 2007 12:27AM
Hmmm...I see. Darwin 1.1....hm.
So, Darwin 1.0 will be not self-replicable?
Re: Support material header
August 31, 2007 03:07AM
My understanding was the waterdrop shape, the one used as the reprap symbol, was chosen/developed because the extruders could produce it without support material.
I don't know if I like the idea of having a right angle in anything that takes stress, but for all I know the corner brackets may be overengineered as it is.
Re: Support material header
August 31, 2007 07:40AM
One question I haven't seen answered it "What is the support material made of?" and "How does it get removed?" Okay, that's two questions.
Re: Support material header
August 31, 2007 07:54AM
the support material we're looking at is polyfilla, or common wall spackle. it can be removed in water.
Re: Support material header
August 31, 2007 08:02AM
How hard would it be to make a head that can extrude various forms of clay and cement? I think such a head would be rather useful, either for making aluminum-casting molds directly, or as cheap filler material. You could then theoretically use any material that comes out as a thick paste, such as your polyfilla or regular backyard clay, as a support material. You might even be able to extrude solder paste with the same head, but I don't know.

-Samuel
Re: Support material header
August 31, 2007 08:04AM
Hmmmm.... spackle takes quite a while to dry. Plasterers will apply it, then go away for a day. Or is it possible to force it to set more quickly by applying heat? That seems like a good material: set it by applying heat, dissolve it by applying water.
Re: Support material header
August 31, 2007 08:44AM
The spackle doesn't have to dry. Mixed with the right quantity of water, it is quite thick enough in its wet form to support an object being built (that's how it stays in holes in walls and such without dripping out as it dries).
Re: Support material header
August 31, 2007 09:29AM
Is there an effort running on building such a dispenser? I am very interested in any dispenser capable of depositing a thick paste like pollyfilla or clays.
Filled resins wich have very varied properties (from conductive resins to heat resistant ones) have that consistency and would use the same type of dispenser.
Re: Support material header
August 31, 2007 09:37AM
Re: Support material header
August 31, 2007 12:31PM
ZachHoeken Wrote:
-------------------------------------------------------
> the support material we're looking at is
> polyfilla, or common wall spackle. it can be
> removed in water.

I haven't had a chance to post any new pictures recently, but i've got my machine to extrude tile grout from a syringe. It prints at a reasonable resolution, at the moment i have a few problems with drift on one of the axis, so i've only tried single layer printing but i hope to get that fixed soon. I tired a few materials and stuck with tile grout because it it thick enough not to run and not so thick it can't be extruded, and also it sets very quickly. It is probably very similar stuff to polyfilla though.
Re: Support material header
August 31, 2007 01:32PM
For Heaven's sakes post some pics, man! smiling bouncing smiley
VDX
Re: Support material header
September 20, 2007 04:12AM
... i had to mix some glass- and gold-powder with a liquid to a dispensable paste.

So i found out, that i can have a high variable and fine adjustable viscosity, if i use either pure dexpanthenol (eq. D-(+)-Pantothenylalcohole) or mix it as needed with water.

Dexpanthenol didnt dry, but with heating i can remove it completely and sinter the formed volume to the endstate - glass-soldering (~430
Re: Support material header
September 22, 2007 11:27AM
Hmmmm..... I wonder what happens if you mix dry plaster with rubbing alcohol and then put it into a syringe? Might set very quickly.

/me goes off to try it. Wish him luck.
Re: Support material header
September 22, 2007 11:51AM
Good luck, but I think plaster needs water to make it set. I expect if you add alcohol and let it evaporate you will be left with powdered plaster rather than a solid.


[www.hydraraptor.blogspot.com]
VDX
Re: Support material header
September 22, 2007 12:36PM
... i used dexpanthenol for manually dispensing of very small droplets (~60 microns) of glass-powder or a mix of eutectic gold-soldering powder with plain gold-powder in 1micron-size.

The paste must preheat and the dexpanthenol have to vanish completely, then i can fire and sinter until 1000
Re: Support material header
September 22, 2007 07:14PM
rubbing alcohol has water in it. But more to the point, plaster of paris is an exothermic reaction, so rubbing alcohol doesn't have much of an effect on it. It hardens even in lack of air, which is NOT what we want. Oh well.
Re: Support material header
September 22, 2007 07:47PM
What if, rather than using a pressurized feed, and controlling the volume by measuring the deposition time, a thinwall tube is used along with a set of rollers which squish the tube against a semicircular path. Like this: [russnelson.com]
You can get a controlled flow as long as the tubing you're using holds its size well enough against the tube.

Hmmm.... but maybe that would work better using a pressurized feed?? Depends on the viscosity of the filler material.
Anonymous User
Re: Support material header
September 22, 2007 10:29PM
RussNelson Wrote:
> What if, rather than using a pressurized feed, and
> controlling the volume by measuring the deposition
> time, a thinwall tube is used along with a set of
> rollers which squish the tube against a
> semicircular path.

Sounds like you're describing a peristaltic pump:
[en.wikipedia.org]
VDX
Re: Support material header
September 23, 2007 08:20AM
Hi Russ,

... it seems, that i have an 100%-dexpanthenol without water in it, when i have it open over weeks, it didn' dry out and i didn't know, if it's hygroscopic ...

It's very adhesive and have an extremely high viskosity, nearly like toothpaste - it flows much slower as honey, but it flows and forms a perfect droplet with a smooth end-surface.

I use it as solvent for heavy powders like gold, platinum, ceramics or glasses.

My mixed up pastes are stable without sedimenting for weeks, so it's a perfect medium.

If i need a lower viscosity, then i can mix with water, but then it dries over hours or days ...

Ciao, Viktor
Re: Support material header
September 23, 2007 10:48PM
Yes, emf, that's the name of it! Thanks!

I've been thinking further about the support / filler material. It really only needs three properties: 1) it needs to support the construction material, 2) it needs to be removable using a solvent that doesn't dissolve the construction material, and 3) it needs to be accurately dispensable.

Note that I said nothing about slump, or hardening. It doesn't need to! You just need to be able to construct a vessel which holds the filler around the part being constructed. Then, the amount of slump doesn't matter. And as long as the construction material doesn't sink into the filler material, you don't need to worry about hardening.
VDX
Re: Support material header
September 23, 2007 11:10PM
Hi Russ,

what about wax?

It's cheap, doesn't need so high temperatures (e.g. lowtemp-wax) and is easy to remove ...

Some synthetics or vaseline can be used too - then it's maybe easier to cool down the apparatus, for stiffening the support material.

With releasing to room-temperature it goes liquid again ...

Ciao, Viktor

*** appended ***

... gelatine culd be a try too - it's easy to liquidize and easy to remove with hot water ...

Edited 1 time(s). Last edit at 09/24/2007 12:13AM by Viktor Dirks.
Re: Support material header
September 30, 2007 06:19PM
Do the green parts on the front page still have their support material attached? It looks as if so.
Re: Support material header
September 30, 2007 08:12PM
Hmmmm..... I think that perhaps the best support material would be something which is soft when heated, sticky, cools quickly to a hard surface, AND is water soluble. Caramel! Or something else involving sugar.
Re: Support material header
October 01, 2007 03:33PM
Hi Russ

Yes they do and a point of interest,it is a pain to get the support material off it does breakaway but only with quite a pull and looks not dissimilar to the product material Adrian might know what it is.

They also start on a very firm foam base and lay down a layer of support material to start with possibly to help the product latch on and start correctly, just a thought.

Ian
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