ceramic slip deposition head

Referring to my earlier post: [forums.reprap.org]

I am going to experiment with reprapping ceramic clay slib to create parts that after baking form ceramic objects. The slib material can range from a clay like substance to a more yoghurt kind of liquid. It dries (and shrinks!) by air. It can also be reinforced with fibers to give it more strength and reduce shrinkage.

Apparently some of you already did work in that direction.
I found 3 possible designs for the head:

- de Fab@home syringe exruder: [eposition_Tools#Model_1_1-Syringe_Tool" target="_blank" rel="nofollow">fabathome.org]
This one would need to be fitted on the RepRap or a similar design. Problem is the small reservoir.

- Peristaltic pump design by Adrian Bowyer: [blog.reprap.org]
This looks very promising. Would love to test this on slib.

- Paste Extruder: [dev.www.reprap.org]
Looks a bit like a syringe head but bigger

Anyone who did experiments with the above concepts or tried different approaches to extrude cold substances that could be useful for ceramic slib? When I have my machine and some first extrusion heads I'm going to do some tests and ask for advice from a pro ceramist for the clay recipes (I only have basic knowledge).

Any help and tips appreciated! thanks.

Best!
dries

Edited 1 time(s). Last edit at 02/02/2009 03:04PM by unfold.

Hi dries,

i built a simplified paste-dispenser - look here for some images: [forums.reprap.org]

It's meant for small volumes (10ml-cartouche with ID-0,15mm-needle for fluid PMMA) and high accuracies, but i have the parts and threads for 50ml-cartouches too.

In another thread i posted some images of different components: [forums.reprap.org]
and a heated paste-dispenser: [forums.reprap.org]

Actaully i'm more active in optimizing my CNC-mill than repstrapping, but it's on my agenda again ...

Viktor

Hi dries,

You might want to take a look at "contour crafting". Probably discussed elsewhere on these lists, but anyway, these folks have some neat videos on youtube of prototype concrete extrusion machines:

[www.youtube.com]

good luck with your project and keep us posted - pumpernickel

hi pumpernickel,
Yes, I've seen those videos some time ago but thanks for mentioning them! A contourcrafting head can be added to the list of possible designs. Although I think that this would mean that the controller software should be altered to for the rotation of the printhead? Sounds a lot like controlling the knife of a vinyl plotter. Would this be hard to add to the software?

Dries

well, i don't know much about the software side. it probably would not be too hard to add another axis to the toolhead (a stepper motor, say) and modify the gcode firmware to control it; and the arduino might not have enough i/o for a new axis so you would need a bigger controller (a sanguino, say) and then the gcode would have to come from somewhere, so you would have to modify skeinforge or whatever is pumping out the gcode... it sounds like a lot of work, but each of the individual steps is not too complicated. It could definitely be done, but it takes a lot of time to debug all the little things...

Consistency of yogurt you say? Do you mind explaining exactly what ceramic slip is? Shrinkage can be a very good thing or a very bad thing, depending on whether or not it shrinks uniformly.

Gene Hacker Wrote:
-------------------------------------------------------
> Consistency of yogurt you say? Do you mind
> explaining exactly what ceramic slip is? Shrinkage
> can be a very good thing or a very bad thing,
> depending on whether or not it shrinks uniformly.

Very good question. from wikipedia:
"A slip is a suspension in water of clay and/or other materials used in the production of ceramic ware. Normally a deflocculant such as sodium silicate is added to disperse the particles and hence allow a much higher solids content to be used. The addition of a defloculant allows the water content to be kept to a minimum which reduces the amount of shrinkage when slipcasting. The mixing can be by hand or more usually in a blunger."

So basically it is clay with water and is mainly used for slip casting. Slip casting ceramic goods is done by pouring slip in a plaster mould. The plaster sucks the water out of the slip. After a few minutes a layer of 3-4 mm clay is deposited on the mould. See the process here -> [www.nymphenburg.com]

I dont kow if slip is the best form to rapid prototype clay. But the deflocculant mentioned above can be used to alter the fluidity. Slip would be easier to extract true a syringe or something similar but will be to fluid. The other possibility is to use normal clay but thats hard to extrude as I suppose. Or a substance inbetween. Many possibilities here, you can even reinforce clay with cellulose fibers to make the unbaked model stronger.

I also want to contact the European Ceramic Workcentre in Holland when I have a working RepRap. They have some of the best specialists but first I need to do basic tests.

The shrinkage factor of wet to dry clay is not that big, basic rule is that the amount of water is the amount of shrinkage.

There are also promising industrial pocesses that I'm not to familiar with but like to explore. basically the use ceramic powder mixed with a range of binders:
[www.substech.com]

Hi unfold,

look here: [forums.reprap.org]

And search the posts with "viktor waterglass" and "all dates" - there we mentioned some aspects of clays and fluid mixtures.

I mixed waterglass with ceramic-dust for embedding high-temperature sensors in ceramic-tubes with 500

hi viktor,

That 'all dates' hint was what i needed, thanks! Have been searching the forums before and did find some stuff about ceramics but I overlooked this setting. Will search again, also for your waterglass posts.
I am also researching a bit into ceramic injection molding (CIM) since they use a thermoplastic resin mixed with ceramic powder. Its pellets as far as i understand. And i can imagine that making a 3mm wire from it is probably impossible because it will be to fragile.

I find the best way to search the forums, and most sites with there own search, is to use Google with site:forums.reprap.org in front of the keywords. Oddly enough Google is better at searching than most built in searches

---

[www.hydraraptor.blogspot.com]

Hi all.

Took some time to digest true threads referring to ceramics besides other work piling up. I really felt stupid missing al this valuable info because of overlooking an option in the search page (one vote for changing the default setting!) and thinking that I wanted to do something brand spanking new .
But in the end a lot of the info was a bit dated so I dont think there is much active development on ceramics. Here's a list of relevant topics I found:

-Late 2007, on sintering ceramics among other stuff: [forums.reprap.org]
-Aug. 2008, also on sintering: [forums.reprap.org]
-March 2007, some notes by OhioMike on polyceramics: [forums.reprap.org]
-March 2008, about ceramic paste extrusion:[forums.reprap.org] (basically same question as mine) Very interesting info in Sebastians post.
-Dec. 2008, short discussion about clay: [forums.reprap.org]
-Late 2008, comments from Mark Ganter on printing ceramics Z-corp style and with Fab@Home: [forums.reprap.org] (his article in ceramic arts daily is an interesting read: [www.ceramicartsdaily.org])

So a more appropriate question would be Whats the state of ceramics early 2009? . Viktor has been very active in most of the above discussions and shared his insights here to.

From all this info my conclusion would be that the best toolhead to start experimenting with is a syring design.
My first step will be to build a basic syringe tool for testing various recipes that I have in mind and checking some of viktors stuff with waterglass eo binders and reinforcements. Something like gelcasting [www.ms.ornl.gov] looks promising too. My main interest is larger scale objects so 2-1mm extrusion nozzles would be fine. Contour crafting, mentioned here, builds on this for vessel type objects but not my focus now since that would require additional hacking on the reprap hardware and software. Yikes, I already have a hard time getting is just to run on my Mac.
Later I would like to test hot extrusion with ceramics mixed with polymers, best would be to have a granule extruder and trow in some ceramic injection molding material but thats also far fetched for now. I talked with a relative of mine who runs a big dental lab but they do not use this type of polyceramics.

Sounds like a good plan? Now I need to hunt for a syringe design that I can base my extruder on.

greetings!

Hi all,

quick update,: I've build a Bits form Bytes machine and it is happily crunching out plastic objects. What a fantastic machine. Of course the first print was a (un-whiskeyproof) minimug. Next step, syringe tool.
Photos are @ [gallery.me.com]

thanks for al the advice!

unfold!

Damn it! Why aren't you blogging this in the builders blog or at least putting a teaser there linking to your pics. That's brilliant print work!

---

-------------------------------------------------------

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

Hi Forrest,

Thanks for your comment! I was a bit surprised by the print quality, expected some more bumps in the road before getting there. Bits from Bytes did a wonderful job on the kit. How can I post to the builders blog?

Small explanation of the prints:

First print, minimug. Surprisingly (to me) successful first print. Unfortunately not whiskey-proof.
[gallery.me.com]
[gallery.me.com]

Set minimugs, 1st: from downloaded Gcode file, 2nd: first try at converting STL with Skienforge (wrong orientation), 3th: Succesfull conversion STL-> Gcode:
[gallery.me.com]

Pony:
[gallery.me.com]

Being a spatial designer, I needed to print one of our own products which was very suitable for printing. An espresso cup that morphs from cross to circle:
[gallery.me.com]
[www.unfold.be]

3d EEG brain scan (3 sec.):
[gallery.me.com]

3 days of printing:
[gallery.me.com]

Paperclip (get it on thingiverse: [www.thingiverse.com])
[gallery.me.com]

Looks like some very Nice results

---

Bodge It [reprap.org]
=======================================

---

BIQ Sanguinololu SD LCD board	BIQ Stepcon	BIQ Opto Endstop
BIQ Heater Block PCB	BIQ Extruder Peek clamp replacement	BIQ Huxley Seedling
BIQ Sanguinololu mounting	BIQ standalone Sanguinololu or Ramps mounting	Print It Stick It Cut it

My rep strap: [repstrapbertha.blogspot.com]

Buy the bits from B&Q pipestrap [diyrepstrap.blogspot.com]
How to Build a Darwin without any Rep Rap Parts [repstrapdarwin.blogspot.com]
Web Site [www.takeaway3dtech.com]

Thanks Bodge It, so far the funniest print has been this self portait made from a 3d scan. You can find it on thingiverse if you want a minime too

Oh wow, I love it - how on earth did you do it?

Hazel

This is from a commercial scan but you could use the free [www.david-laserscanner.com] for this. More work but good results.

Updates!

After a pauze to do some other stuff I actually got back to the reason why I got into RepRap in the first place: printing ceramics.

At the moment I have done the first tests using something along the lines of the Makerbot Frostruder MK2 design
I have started a blog about the progress at UnfoldFab so there you will get updates about it.

Today I also found a very relevant link in a reaction at my original intro topic . This is actually exactly what I was trying to do: robocasting

To relay some useful conclusions here:

• While initially enthusiastic about Zach Hoeken's pressurized syringe tool I am after two days a bit skeptic about how controllable this process is. I had to remove as much distance as possible between compressor and extruder to prevent pressure build up in the tubes. I will try soon with a separate pressure controller that I can mount close to the extruder and that is much more presize that the system build in the compressor. But what worries me more is that the flowrate is dependent on the pressure AND the mixture of the clay and so far it is hard to get that very consistent true different batches. Its a nice test bed but I think i will need to build a stepper driven tool to compare.
• We-Need-Software... And we plan working on it. Skeinforge is not very useful when you want to build single filament wall objects and when you really want all the control you can get over infill structures etc. For us this is not so much about reconstructing 3d object but about using the very form language of FDM but in different materials. What we want is a tool in which you can draw gcode lines. At the moment we are looking at a Gcode import/export plugin for Illustrator using Scriptographer. Yes, AI is not 'free' but it is what we know best. But we'll trow the plugin out for anyone to use.
• Rapman is definitely not intended for wet slurries, the design is very open. An air bubble can trow around some mud and dry clay gives lots of dust. Will need to look at a system to cover some parts ore have a closed build area. Thinking about a paper/plastic bellow around the build area.
• Object stay flexible true the build and hours after so one rapid move from the extruder can deform parts of your object.
• No idea why objects taper, shrinkage?

One photo of some tests (more in the blog):

Edited 1 time(s). Last edit at 01/16/2010 01:46PM by unfold.

I apologize in advance if you already know about this, but I just read about "precious metal clays" that that can be used to make "solid" metal jewelry pieces. You sculpt the clay then fire it (bake it in a kiln). They have silver, gold, bronze and copper clays. It seemed interesting to me. BTW, I would love to buy one of your creations (especially if it was in silver.

Ben

Unfold, that's utterly cool.

Have you tried firing the clay pieces yet?

Sebastien, they are waiting till the kiln is full
Should get my hands on one of these ultra small 1 liter kilns

copy from unfoldfab

The future's here baby! (first successfully printed ceramic vessel)

We took some time to play around and get used to the dynamics of the clay print process. It was also time to step up (or down?) the resolution from 1.9 to 0.8 mm using screw-on luer lock tips. We are also now using powder clay that can be mixed in exact quantities instead of moisturizing chunks of clay. Also figuring out ways of reliably filling the syringes without trapped air. I'm using a similar 60cc syringe where the front is cut off and use this to suck in the clay from the mixing bowl. Then the clay is transferred to the print syringe, this works really well actually.

After some calibrating I decided to print a test design that would be hard to make using conventional techniques: a double walled vessel with fins connecting in- and outside. I was expecting mostly failure but it finished without to much trouble! Due to the restrictions of Skeinforge expecting 3d models, the walls are double filament (1.5mm total). As you can see on the Pleasant3d view there is an outer and inner shell and instead of a line connecting both there are o-loops. Testing a different design now that enables us to test a single filament double wall vessel. But in the end We will need a way to generate tool paths from single walled surfaces instead of solids

Last weekend I talked briefly with Adrian Bowyer after his excellent talk at FOSDEM. I was excited to show him our results after he finished his talk with mentioning ceramics as future possibilities (hence the title, wink, wink)

More images and video in our gallery

Now lets pray all together that trapped air bubbles won't make it pop...

That is a lovely piece of work! Congrats!

Apparently I'm not the only one who thinks so:
[www.boingboing.net]

boingboing gets ~2M unique visitors per month, maybe. Wow.

---

dries,

Would you like to upload some or all of your work to the wiki?

We have one entry here:
[objects.reprap.org]
but your work and configuration seem novel and different,
so maybe at:
[objects.reprap.org]
or
something similar, using the example page:
[objects.reprap.org]
as an example?

---

Also I was wondering, is it time to create a dedicated paste-extrusion forum? We've got a lot of syringe and ceramic stuff that I can refile into it.

Or is it better to keep everything under the heading of Extruders and Materials?

---

-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!

I've created a stub page here "Unfold Clay Results":
[objects.reprap.org]

Hi Sebastien

Indeed, got some mails from friends all over that found the boinboing post when reading the morning news. It got repeated at Wired, Makezine, Switched, open3dp, openmaterials ao. Nice.
Thanks for setting up a template, a syringe/paste forum could be nice to bundle the work. I will take some time to write up everything after 13th of march. We need to finish this project for an exhibition 'Design by Performance' that opens 13th at Z33, Belgium. Growth Modelling Device by David Bowen will also be shown there (reprap based growing union copying machine)

[www.z33.be]