Tuesday, December 28, 2010

Working Method - Jonathan Keep

Having just got my first printed ceramics outof the glaze firing I thought it would be a good time to offer a post on my current working method. On and off for the last ten years I have been using 3D computer modelling programs, mainly as a tool to train my visualisations memory and explore new forms. Using numerical transformations the computer can generate forms I would not otherwise conceive of. Scaling, particularly uneven scaling or scaling only in one direction I have always find interesting. The human eyes aptitude for responding to symmetries is another area I have explored both in 2D and 3D software. Morphology and the evolution of form is a third technique I use. The 3D program can calculate the transition from one form into another offering the possibility to capture a new form at any point along that transformation.

Recently I have started using Blender, an open source 3D program that offers great possibilities and I can see myself spending a lot of time with it. Unfortunately the most recent version does not yet have .stl export, the file type used to convert to code that the ceramic printer understands. So saved as .obj files I do the conversion to .stl in Netfabb Studio. What is useful in Netfabb is that the surface area of the form is given so I can make the necessary adjustments to make sure I will be able to print the object from one 60 ml syringe of clay paste. The saved .stl file is then opened in the BfB Axon program and finally the form is cut up to make a g-code file that goes on a memory card ready for the printer. The BfB Axon program has a minefield of settings that are required when using a self made printing head as with ceramics. This is another posting in itself and while I am still trying different syringes ( I want to be able to hold a greater volume of clay for each print) it will be a while before I know what my settled ceramic print head settings will be.

Three stages in preparation for printing – Blender, Netfabb and BFB Axon.

Morphology of glazed printed porcelain forms – height 9cm each.

Simple glazed printed porcelain scaled forms – 6 to 3 cm high.

Thursday, December 23, 2010

Shipping robots

I unpacked one of our printers that came back from an exhibition in Abu Dhabi last november and found that two of the four corners where completely loose, thats four grub screws for each corner that popped out of their place so now the vertical bar slides freely in the corners.
Funny thing is that when I unpacked them in Abu Dhabi, the crate was damaged and not very rigid anymore but the printer wasn't. I fixed the crate before shipping back and now it is the opposite.

Looks like I will need to take this one apart and reassemble correctly again, he was a bit wobbly in the first place...

And I will need to look into ways to better pack the machines, I always fill the crate with foam. Also on the bottom there is 3 cm foam in which the feet are plugged so the foam sits flush with the horizontal bottom bars. Will need to look into ways to improve this.

So fellow robot travelers, how do you ship your machines?

Tuesday, December 21, 2010

Kilns part 1: OpenKilnController

Last Christmas I got a small, almost new 8 liter kiln from my uncle who owns a large dental lab. He got it when he bought a whole lot of material in a liquidation and it was to big for them. Small for us is large for their industry, they use tiny desktop kilns, maybe 250 cc that fit a few tooth in them. The only problem was that it was only the kiln with the heating elements and no controller, thermocouple or relays. Buying all the necessary gear through our local pottery supplier would have made us ± 600€ lighter! So having a little tinker ethos I figured that it would be easy to build something yourself using an Arduino as a controller and a Solid State Relay to switch the 2 Kw elements. Not being such a great programmer or electro-engineer I dived into google thinking that this must have been done before considering the prices of commercial controllers,  some code would probably be available to get you started. Well, google turned op close to 0 hits so apparently there are not enough potters with programming/engineering background or hackers that like clay? After doing lots of research, driving to holland to pickup some old analog industrial temperature controllers, thermocouples and relays, requesting manuals for gear from the 80s from japanese companies I finally threw in the towel and bought a 300€ controller kit that was a perfect fit for small kilns like ours. I found this kit through all the googling (so never a waste of time) and figured that it was not worth it to continue my search for a DIY solution since I really lack the skills to pull it off from scratch. The ST222 kit I bought included a controller, thermocouple and relays and was made buy the UK company Stafford Instruments. So here's our inferno in a box.

I still love the idea of a DIY kit controller, I calculated the costs of a DIY solution to be around 150€ (Thermocouple 60€, Arduino 30€, SSR 30€, Display for Arduino, buttons etc 20€) which was a quarter of the initial commercial solutions and would allow you to preprogram all curves from a computer instead of using the awkward interfaces of commercial solutions and even monitor the kiln with plotted curves on the computer. The solutions on the market are really basic in functionality. While the 300€ controller was a sweet enough deal for our small kiln I still think a DIY controller would be very interesting for larger kilns. So I hope someone wants to pick up my mission for the OpenKilnController.

Here is what I have found so far, kiln controllers are PID controllers (I never heard of them, remember my lack of skills) and they appear to be very common in industrial control systems.  There is already a pretty decent PID library for Arduino. (http://www.arduino.cc/playground/Code/PIDLibrary) that could be used as a starter. The hardware is straight forward as mentioned above, you need a thermocouple as analog sensor, the Arduino with PID library as controller and a SSR as switching mechanism for the kiln. The tricky part looks to be the 'tuning' of the P, I and D parameters.
I also found some rforum posts over at arduino about 
DIY Arduino PID controllers so at least some people tried like PWillard.

UPDATE: While typing this post I revisited the forum thread I mentioned above and apparently GlennD did build a kiln controller for a glass fusing Kiln. Unfortunately only after I bought the ST222.

Sunday, November 28, 2010

Introductions - Jonathan Keep

Jonathan's post (Read An Englishman in Antwerp bellow first):

I am an artist potter based in Suffolk, England and for some time have been interested in studio based 3d ceramic printing so to find out earlier this year what Unfold have been doing was a revelation. Eager to replicate their system I visited Claire and Dries and now have my own RapMan oozing porcelain paste in my UK studio. With a desire to continue Unfolds generosity in sharing knowledge I plan to post my printing progress on the Unfold-fab blog to keep all the information in one place on the web.
My RapMan supplied by Bits from Bytes, Somerset UK is version 3.1.0 loaded with software 4.0.2. Building the flat pack went ok and I had it moving in three or four days. Not interested in printing plastic I have not put the print head together. Wanting to concentrate on printing clay I got on with putting that together.  My ceramic printing head is very cobbled together with bits of gas kiln equipment as I am well aware that there are still lots of development work to be done and so I just wanted to get started to develop from experience.
My starting point is, as developed by Unfold, a 50/60 cc plastic syringe held in a self made cradle attached to the RapMan printer head mount. The syringe is then pressurised from an air compressor -  that I fortunately already had as I have a spray gun for glazing. The one thing I had to go shopping for was the 1K Ohm resistor that bridges two points of the unused print head cable connector plug on the printer control board. This gets RapMan software to think a pen tool is fitted.

Differences from Unfold –
  • I am using a manual switch at the printer head for air pressure control rather than an electronic solenoid valve. This is for simplicity and so far has worked well as I can stop and start clay ooze as I want.
  • I am using a 1.5 nozzle size as my prints are single walled. My thinking is to duplicate conventional pottery coil building techniques. I have set the Z (vertical axis) increment to 1 mm. So a syringe takes about 20 minutes to empty/print and a tall form can be about 10 cm.
  •  I am printing onto pre prepared wades of clay so do not print a base. This does mean I need to get into the gcode in text editor and cut out some code.
  • I use a (not very good) hairdryer as I print to stiffen up the form as more clay gets layer on. 
It has been a week since I got clay oozing and the learning curve has been steep but things are happening and the development put in by Unfold has been invaluable. In which direction all this might go I do not know as ideas and possibilities keep coming but I am making pots. There are still lots of problems, with gcode, with how RapMan behaves, with the limitations of the syringe size but I have a tool I understand and can customise to my ends and that I feel has fantastic creative potential. 
There have been post on how to fill a syringe; well I have to add to that. Having a wall mounted clay extruder in my studio I made a simple turn and lock fitment to take the syringe on the base plate. I fill a plastic bag with the clay paste (my mix is 1 water to 2.5 porcelain clay powder) and stuff the bag into the rather rusty extruder. Put in the plunger and extrusion arm and pull down. Result filled syringe, and so easy to attach the next syringe for a fill.
For further information on Jonathan’s work see – www.keep-art.co.uk

Thanks for sharing Jonathan!

An englishman in Antwerp

Early last summer we got a friendly email from Jonathan Keep, a British potter who was very enthusiastic about what we achieved with 3d ceramic printing. His email kind of popped out between all the other emails of various people who are interested because Jonathan had been playing around for some time with the same idea of a robotized coiling machine based on a Reprap. Unfortunately he did not find time/budget to pursue the project at that time. Luckily for us ;-)
This was before Bits from Bytes started lowering the barrier by offering an easier (than starting from scratch with Reprap) platform to bootstrap this kind of experiments from. Without an XYZ robot to toy with, Jonathan managed to do some 'analog 3d printing' using a hand operated syringe and the results that he attached to his first email where fascinating and impressive to see:

His email ended with the plan to apply for a grant that included buying a BfB machine and doing a field trip to Unfold's office in Antwerp....

Fast forward: Jonathan came to Antwerp with his wife last october and we had a great afternoon (with tea mind you), it was great to exchange ideas. Here you see him using the virtual pottery wheel from L'Artisan Électronique like only a real potter can.

And a great snapshot of Unfold/Keep work:

Jonathan finished his Rapman last week and crafted the first objects with it. He will be posting to the Unfold ˜fab blog too and we are looking forward to what he will produce and post. We already feel the urge to finish the next claystruder prototype of which many bits 'n pieces are laying around in our studio because of the healthy 'competition' Jonathan put forward :-) 
The first post will be copy paste below until we can find how to add contributors. We also want to put a bit more effort in the Unfold ˜fab blog and post a bit more frequently from now on.

Tuesday, October 19, 2010

3d printed ceramics and video on show at Digital Solid expo

3d printed ceramics and video on show at Digital Solid expo at the Galerie de l'Ecole Supérieur des Beaux-Arts in Valenciennes, France.

info in french:

L'exposition  » Digital Solid / Design numérique » présente les travaux de plusieurs designers et de plusieurs ateliers numériques académiques ; François Brument, Ammar Eloueini, Mr Mann, UnFold/Claire Warnier et Dries Verbruggen, Studio lo, Innovathèque, François Clochiatti, Digital Knowledge/Studio de Projet de Master 2/ Ecole nationale supérieure d'architecture de Paris – Malaquais, l'ISD Institut supérieur de design et le Laboratoire numérique de l'Ecole supérieure des beaux-arts de Valenciennes. L'exposition comporte un volet pédagogique et didactique sur le prototypage rapide réalisé en partenariat avec Innovathèque du FCBA. Elle s'inscrit également dans le programme semestriel du Laboratoire numérique de Valenciennes et de l'Atelier numérique de l'Ecole supérieure d'art et de design de Saint-Etienne.
Ce projet ambitionne d'initier un réseau de compétence permettant la conception et la réalisation à distance de projets de design, la mise en place d'une plate-forme de recherche.

Certaines hypothèses seront expérimentées dans le cadre du projet « L'appartement, une métaphore du monde » au centre d'art Lab-Labanque, à l'occasion de l'évènement culturelBéthune 2011, Capitale Régionale de la Culture.

Lieu :
Galerie de l'Ecole supérieure des beaux-arts de Valenciennes
132 avenue du Faubourg de Cambrai
59300 Valenciennes

Infos :

Friday, October 8, 2010

‘Yes, we’re open.’

UDATE: The full setup of L'Artisan Electronique will be only on display at the opening and the weekend of october 14-16

Friday October 14, 9.30u-15 u
Saturday October 15, 9.30 u – 15 u
Sunday October 16, 14 u – 18 u.

For those who are in the neigbourhood, tonight is the opening of ‘Yes, we’re open.’ An exhibition curated by our long time friend Thomas Lommée from Intrastructures who you might now for his open-standards-for-things project OpenStuctures. We will be showing a new compact version of L'Artisan Electronique (v1.5) which we have been developing along side an improved clay print head and new virtual throwing wheel software (not included yet, those will premier in at Abu Dhabi Art beginning of november).

‘Yes, we’re open.’ is an exhibition on how our networked society is reshaping the way we create, produce and consume.  You can download a great Exhibition overview + open design manual done by Thomas at http://www.intrastructures.net/yes_we_re_open.pdf

8 october - 25 october, 10h - 21h
Budascoop, Kapucijnenstraat 10, 8500 Kortrijk

8 october, 18u30 - 22u30

Please be welcome!

The exhibition ‘Yes! we’re open.’ is part of the Innovation Festival Kortrijk.

Monday, September 13, 2010

missing photo's

Ok, learned a hard lesson. Was cleaning up and splitting my iPhoto library into separate libraries. Noticed only later that everything that I had deleted in one gallery was also removed from MobileMe. Will fix the broken links coming days.

EDIT: fixed

Thursday, August 19, 2010

Filling a syringe

Second post today, I'm catching up while sitting next to a humming Rapman printing a batch of ceramics. Unfortunatly I need to keep an eye on the flowrate and correct pressure or printhead speed every few minutes. More on that in another post. Luckily the Rapman has manual controls. turns head-adjusts speed-back to typing. Yesterday I was going through the excellent documentation of the frostruder at Makerbot. All goodies that where not available when I started, frostforge.py looks very usefull for adapting to Rapman. turns head-does not adjust speed-back to typing. On the Frostruder usage page in the wiki I found the following photo's of Zach filling a syringe:

I used this method exactly once :) Its totally unusably for getting a syringe filled with clay and trying to avoid any trapped air. So here's the method we hacked together in a few minutes.

The Syringe Transfer Tool!

The STT is a syringe from which the front is cut of and that is used to suck up material.

You still need a canister or lump of air free material but thats easier than to try and get the material compacted in every syringe individually. turns head-does not adjust speed-back to typing. 
Next step is to fully insert the plunger in the syringe and suck up material. The trick is to pull the plunger while simultaneously pushing the syringe in the material. After 100 times you can do it one handed while taking a picture :)

Now you detach the plastic plunger stick from the silicone plunger cap without letting air in (tricky part). After that you smooth the clay and taper it a bit, I always put little pit in the top to make sure air escapes before the clay reaches the nozzle when transferring the clay in the print syringe.

Onto the magic transfer move.... You make a nice stack of pssst-turns head-perfect print finished. A nice stack of plunger stick - STT - empty syringe and you push the clay out of the STT into the empty syringe, et voila! 

Clay recipe

I get the question often "is this special clay?". I always said that it was fairly standard but since I have been diving deeper into clay it looks more and more like there's a whole other universe in that slurry. Its not pottery, its higher chemistry and I wish I stayed a bit longer in ceramics class :)
At first we tried watering down modeling clay and this works but its hard to get consistent results. Now we always start from clay powder that you can find in the better ceramics supply store. I found out lately by buying a different type of clay that I had been lucky with the first clay that I bought because the last one had a really tough time NOT to collapse during print. The difference? Fat or lean clay, the one I always use is semi-fat (or semi lean, depends on your ideologies) and the one that collapses is lean. I can't find a good explanation in english online but fat clay particles are more plates and have a better cohesion. (if anyone has the explanation somewhere in english?)
So you'll want semi-fat or fat clay for 3d printing with extrusion. Next you need to balance the viscosity so that it extrudes around 4-5 bar (60-70 psi) but has enough strength to support itself as a build object. A water : powder ratio of 1 : 2.2 gives the best results for the clay powder we use here, this may vary for the powder clay you buy in the store but this might be a good starting point.
You could also reinforce your clay with cellulose fibers (paperclay). I have only done a quick test to see if it extrudes but did not build an object with it. I can imagine that it clogs faster.

Next post: how to fill a syringe.

Wednesday, July 28, 2010

Claystruder 1.1 uploaded to Thingiverse

Took some time to update the files of our Claystruder for Rapman prototype and uploaded them to Thingiverse.

Claystruder 1.1 by unfold

Its a slightly improved version of the one we use for printing our initial ceramics objects. I made some parts stronger, fixed some errors and enlarged the part where the top section of the syringe sits so that it would fit more brands of syringes. The design is based on the Frostruder by Zach Hoeken from Makerbot but uses one double action solenoid valve instead of two single action ones.

It is important to note that it was never designed with elegance or easy printability in mind, its just a quick and dirty prototype.

New Packaging

We have shed the default style and put this blog in a new packaging!

source: http://www.underconsideration.com/brandnew/

Tuesday, July 6, 2010

Anish Kapoor - Grayman Cries, Shaman Dies, Billowing Smoke, Beauty Evoked.

Some months ago we showed our first print tests with little square and round objects to a friend of us and  she pointed out that it really looked like a scale model of a recent artwork by Anish Kapoor: Grayman Cries, Shaman Dies, Billowing Smoke, Beauty Evoked. While we do know most of the work by Kapoor (you might know him from his turbine hall installation at Tate Modern) we hadn't seen his latest work yet. Looking at the images below you can probably imagine our surprise when we looked it up. That does indeed look like extruded slurry deposited with a 3d printer! In fact it is concrete and after googling some more we found the company Factum Arte that pulled this together. Factum Arte is a workshop based in Madrid that works with major artists and institutes on the production and conservation of artworks using various techniques like 3d-scanning, 3d printing, milling etc. They documented the process very well on their website here and here. You can also find all the movies on their Vimeo
Lovely quote: The Identity Engine is a shit machine that farts and craps its way along its ordained path, transforming concrete into stigmergic, self-organised structures. Wounds and gashes, pleats and folds emerge at will and either self-heal or continue to rupture. (excerpt from Unconformity and Entropy)
Some observations:
-We would really like to know more about pumping systems. While a frostruder style syringe head works as a proof of concept printhead for testing materials and software settings, it is not a good solution for producing useful objects because you are very limited size wise in what you can print without swapping syringe, a procedure that brings a whole lot of problems with it. The first step will be trying a larger reservoir on the side, something like an electronic caulking gun. But we need to brainstorm with some more people on this, time for a forum thread!
-Delcam software is used to drive the printer.
-In one video a little piece is mounted on the nozzle to smear all the slurry that rises above the nozzle output, smart because in our experience the quality of the print decreases if there is material piling up around the nozzle.
-Its not printing continuously, they can start/stop the output fast. No idea if this is done by the pumping system or with a valve at the nozzle.
-Support material is sand thrown in by hand, funny :)

Thursday, June 24, 2010


Our machine is finally back in the studio for a longer time so expect some updates. First experiences with glass for example. Stay tuned.
Last week we gave a talk and demo in Basel at Hyperwerk. Hyperwerk is an institute for post-industrial design (love that title) and feels like a large fablab/hackerspace but one where you can get a bachelor degree :)
They will start using a Frostruder and Makerbot for printing all kinds of material including ceramics. Besides a Makerbot they have a Mendel, ShaperCube and immediately ordered a RapMan after seeing ours. I am looking forward to their results!

Hyperwerk chief Mischa looking at a CNC styrofoam cutter

Thursday, May 13, 2010

One exhibition, two repraps, lots of other great projects.

It has been quiet for a while, not because we weren't working but the opposite :) So expect a few posts in the coming days.

What was taking our time? Art centre Z33 in Hasselt, Belgium commissioned Unfold to create an installation 'featuring a 3d printer' for the exhibition "Design by Performance". The Installation is called L'Artisan Electronique and combines traditional pottery craft with 21th century digital techniques. Its still on display till the end of May. If you happen to be in the neighborhood, we will be operating the printer the 29th of may.

From the catalogue:
The world of design has been witness to how the boundaries between art and experimental design are becoming ever more blurred. The exhibition ‘Design by Performance’ is a showcase for performative trends in contemporary design, which focuses not on the production of a finished product, but on the production process itself: objects whose realisation is a continuous project, affected or formed by either the environment, the specific situation in which they find themselves, or onlookersAs such, processes and performances constitute a crucial part of Design by Performance, thus lending the exhibition its unpredictable and spontaneous character, and converting what is otherwise a pure ‘exhibition space’ into a space for events, interventions and actions by designers, artists and the public.

Atelier NL (NL), Maarten Baas (NL), Pieke Bergmans (NL), David Bowen (USA), Oscar Diaz (UK), Edhv (NL), Front (Sw), Martino Gamper (UK), Simon Heijdens (UK/NL), Eric Klarenbeek (NL), Sofie Lachaert & Luc d’Hanis (B), Laurent Liefooghe (B), Lawrence Malstaf (B), Bruno Munari (IT), Markus Schinwald (Au), Studio Glithero (UK), Studio Libertiny (NL), Tjep. (NL), Unfold & Tim Knapen (NL/B)

For L’Artisan Electronique, Unfold created - aside from the ceramic printer you all know - a virtual pottery wheel in collaboration with Tim Knapen. This pottery wheel gives visitors a chance to ‘turn’ their own forms. At regular intervals, a selection of these designs is printed in clay and exhibited in the space.
In L’Artisan Electronique, pottery, one of the oldest artisanal techniques for making utilitarian objects, is combined with new digital techniques. The virtual pottery wheel was realsied by means of a 3D-scanner and digital design software. However, the installation still clearly refers to the artisanal process of working in clay. The printing process imitates the traditional technique used by ceramicists, in which the form is built up by stacking coils of clay.

The other Reprap on display is in David Bowen's Growth Modeling Device that has been featured on a few Reprap blogs in the past. Its a fantastic piece that copies a growing union plant at regular intervals. David, who together with his wife also happen to be wonderful people, build his own Darwin style printer using a Makerbot extruder and gen2 electronics. The fun thing is that the printer has no top frame and is still very stable. I think he did a better job at integrating the Reprap technology in his installation than us, we didn't try :) More info at http://www.dwbowen.com/gmd.html

Friday, February 19, 2010

Hello Blogosphere

This blog was originally intended to share our progress with fellow reprappers in modifying a 1000$ Rapman to print clay. But this post was picked up by BoinBoing two days ago and spread to Wired, Makemagazine, Openmaterials, Switched and Open3dp. You've got to love the internet, yeah! We got lots of great responses, questions and emails. For the new visitors that missed the previous discussions in the Reprap forum here and here and some other places we decided to write a follow up on some of the comments and to clarify some things:

-Unfold Fab is a blog by spatial design studio Unfold, check our website to get an impression of what we do.

-We use a Rapman from Bits from Bytes which is an everything-in-on-kit version of the open source RepRap project. Highly recommended machine!

-We will present our research as part of the Designed by Performance show at Z33, Hasselt, Belgium. The installation L'Artisan Electronique will feature a Rapman with Claystruder and a virtual trowing wheel that scans 3d hand movements and generates virtual objects that will be printed at a later time. The installation is a collaboration with Tim Knapen. David Bowen will also show his Growth Modelling Device, a Reprap based installation. More on this show soon.

-Is this the first use of rapid prototyping/manufacturing technology in ceramics? No, definitely not and some bloggers understood the posts title as if this was the first printed ceramic vessel EVER in the history of mankind.... Ceramics has been made before using expensive rapid prototyping machines, there is the work of Marc Ganter's team from U of Washington and John Balistreri from BGSU. Both use Zcorp printers with modified binders and clay powders. Then there is Robocasting which uses a very similar technique to what we are doing: clay extrusion. Also the work done on large scale concrete printers has lots of overlap like Contour Crafting developed by Behrokh Khoshnevis or the concrete printer used by artist Ansih Kapoor made by Factum Arte. There was a post in the pipeline explaining why we are doing extrusion and how it compares to the powder/binder based process, we'll post that in a few days. But as far as I know this the first ceramic vessel done on a sub 1000$ rapid prototyper! :) I think Switched.com got it right as to the importance of this affordable hackable technology being in the hands of designers:
With reasonably priced 3-D printers hitting the market, and DIY versions becoming more prevalent, we're now entering a very exciting time in which designers are experimenting with the materials they send through their extruders. We wrote back in November about Belgian design outfit Unfold and the Utanalog teapot it displayed at the Bits 'n Pieces Exhibition. Now, Unfold has successfully used its 3-D printer to print an earthen vessel from powdered ceramic material.
-Its not powdered ceramic material as in the Zcorp process. Clay is a suspension of minerals in water and the Zcorp based system kind of makes clay in the print process by adding the binder. We use clay as a print material and we use clay powder just to make clay that always has the same consistency. Sounds high tech to some but this is standard pottery techniques.

-Someone pointed out that it is technically not ceramics until it is fired and he/she was absolutely right but this is corrected as per the previous post ;)

-Can this be smoothed? Sure, dry greenware objects are very easy to sand or you can smooth them when still wet, many options and we'll do some tests on the next prints. We like the traces of 'making' on objects and thats why we left them rough.

Successfully fired

We bisque fired everything at 1000°C and all tests came out of the kiln perfectly which is very encouraging. Air doesn't seem to be to much of a worry. Yes, those are Utah teapots :)

Sunday, February 14, 2010

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)

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

More images and video in our gallery [note 04-2015: gallery is gone)

ps. Sorry Erik for the missing reference, its 70 x 70 mm

Thursday, January 14, 2010

Hello slurry World!

Here they are, the first extrusion tests with white baking throwing clay. All in all I am pretty happy with the initial results and the design ideas for rapid prototyped clay products start flowing too :)

The first set shows some prints with a Gcode file that turns the extruder's solenoid on and off for each layer. The benefit of the pressurized extruder should be instant on/off but apparently I have to tune some parameters to get to that. Off was very instant but repressurizing took considerable time. In this example you can see various pressure settings (3,5-5 bar) and as a result the extrusion gets thicker and the restart is quicker. The clay is probably a bit to thick, it didn't work at all straight from the pack so I mixed it with some water by hand. So maybe when it is more fluid, use a smaller orifice (add short a blunt needle), run quicker and higher pressure I could get instant restarts? I am also going to try not to depressurize the syringe by closing the exhaust. I hope that when I can keep some pressure that it will be easier to find a balance.

For the next tests I just removed all the start/stop code for the solenoid in between layers and got pretty good results, I should increase the Z speed to get thinner blobs when going to the next layer. The slightly thicker squashed extrusion (back left) gives much more reliable builds.

Here you see some 'solid' object, this are various stages of a cube with sparse infill and two solid layers  aborted somewhere in the print. The solid layers need some adjusting and I really should learn how to calibrate my machine, something I always run around. For all this tests I just set the layer height in Skeinforge to 1.4 mm and left the rest as is (except the amount of perimeters, infill ratio etc). In the bottom left example you see what happens if you run out of clay... A little air blast. At ths stage I got really enthusiastic about the possibilities for this mashup of old craft and new tech. This types of structures are very hard to do in traditional ceramics and we have some initial ideas with this.

Some less successful examples ;)

Lessons learned and questions unanswered so far:

  • 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 precise than 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?