Printing Clay at the Resolution of Plastics

  • Hello all,

    I had a nice chat with @T3P3Tony at the East Coast RepRap Festival this past weekend, but unfortunately a laptop issue prevented me from demonstrating the printer. I thought I'd share a few links about this experimental effort, for Tony and anyone else who might be curious about clay extrusion.

    I've been very focused on trying to see if clay can match FDM polymer printing in terms of resolution and form complexity. After a few years of work nothing has convinced me this is untrue, though there are some areas where things have gotten difficult.

    So here are some links relating to high resolution (in the context of extrusion) clay printing:

    I've built a small one and a larger version with two extruders

    The print nozzles I'm using are cake frosting tips, which have been great to work with - cheap, stainless steel, easy to replace. The best cake frosting tips I can find have come from the UK, like the Duet itself.

    I'm an artist/teacher using this for art purposes, but also interested lately in architectural possibilities. Some finished objects can be seen here.

    This is an open source project but also very much a work-in-progress. Thanks for checking it out if you made it this far!

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    Very cool. A clay printer is definitely on my bucket list. I love the look of the finished pieces.

  • very nice.

    have you tried the vase mode to make a vase?

  • Awesome, thanks for sharing. What type of clay are you using, you have to make a special mixture or? what type of feeder, the compressor, suringe or some type of moineau pump?

    I assume you followed up on the work of clay printing pioneer unfold ( ) on rapman ( e.g. ) ... he was pretty successful with clay printing back in the day.. no clue where he is at now nor where it all led finally 🙂

    I'm attm testing the clay filament by Kai Parthy .. dunno if you seen it, you can print it with "normal" 3mm extruder, it's not 100% clay, it's a filament that melts but than you can put it in kiln and it will become porcelan 😄 (or how you called baked clay 😄 ) .. it might be interesting to you too 🙂

  • @tom_lauerman

    Awesome! Thanks for sharing. What do you use to push the clay into the nozzle (i.e. your equivalent of our filament extruder)?

    Also to improve bridges and overhangs we blow cold air on the molten plastic. Have you ever experimented with blasting hot air at the clay to achieve similar?

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    @tom_lauerman It was excellent to meet you at ERRF. For everyone who has not seen Tom's parts in person they were both technically interesting and very attractive art! This one was my favourite:

  • @Veti Yes, vase mode is well suited to vase making! I'm generally working more with sculpture and architectural forms, but several others are doing fantastic things with vessels. My favorite in that realm is Jonathan Keep.

  • @smece I've used many types of clay - earthenware, stoneware, porcelain, etc. The formulation is not totally essential but the water content is. Also, large particles can clog an extruder so one has to use clays that are well matched to a particular nozzle aperature. I have exchanged probably thousands of forum posts and emails with Unfold studio! I have yet to meet them in person sadly, as they are in Belgium, I'm in Pennsylvania, USA. I love Unfold's work and they are always keen to share ideas. The Kai Parthy filament is interesting. I tried a sample a few years back, but I had difficulty with its brittleness. As a person with many years experience working with clay I was eager to work with wet stuff I am so familiar with. I'm sure amazing things could be done with Kai's filament.

  • @deckingman Thanks for your interest! I'm using a mechanical syringe with an auger assist at the printhead. Put another way, there is an extremely powerful piston which displaces the clay out of the nozzle. This is coupled with an auger screw which regulates the flow rate of that displacement. (Hope that makes sense!) Its a fully mechanical system, no air compression - and all of it controlled by the Duet.

    One could try and heat the clay as it exits, but clay does shrink as it dries, and uneven, rapid drying is the principle cause of warping and cracking. So, one would have to apply heat carefully. Personally I think it will be easier to design and print a combustible support material than to rapidly dry the clay as it is bridging.

  • @T3P3Tony Many thanks! I hope to be back at a similar event such as MRRF or next year's ERRF with a more robust setup. The small printer is something I've barely even tested at this point, but the big printer is too big to exit the room in which it was built.
    I was happy that ERRF was full of all kinds of works-in-progress and non-commercial projects like mine. Got lots of good ideas and feedback. I'll be demonstrating multi color clay printing at a ceramics conference in the spring (NCECA), but that conference is 99% not about 3D printing. On the off chance there are Duet forum users who attend NCECA (@3DPotter might be the only other one) come check it out.

  • @tom_lauerman Thanks for that, and you are talking to a retired mechanical engineer, so it makes perfect sense.

    Off topic I know but have you heard of Delft pottery? It's well know in Europe. I'm in the UK but we were in the Netherlands a few years back and visited the Delft factory. They told us that they actually import their clay from Cornwall in the UK. So if ever I give this go, I'll know where to get clay from.☺

  • @deckingman Yes, Delft clay is well known worldwide, beautiful stuff. A lot of the porcelain we use here in the states is also of UK origin, so we always curse the shipping cost. Probably the best porcelains in the world are in China, but maybe the brightest white clay in the world comes from New Zealand and is a type called Halloysite.
    That said, I don't always prefer porcelain. Simple red terracotta clay can be found anywhere in the world (I think) and is wonderful stuff to work with.
    Its a lot like filaments I guess, and maybe porcelain is like some exotic nylon that is difficult to print, but terracotta is like PLA (if PLA had a 30,000 year history of use). Not a perfect analogy!

  • @tom_lauerman said in Printing Clay at the Resolution of Plastics:

    I have exchanged probably thousands of forum posts and emails with Unfold studio! I have yet to meet them in person sadly, as they are in Belgium,

    I'm much closer to him geographically but in 10+ years I never met him in person neither... (must admit have not spoken to him in ~6 years 😞 .. time flies)

    but I had difficulty with its brittleness

    dunno if you had a chance to check out eSUN filament boxes? they solve this problem 😄 as they preheat the filament, you can chose the temp zone (1-4) and how long you want it to heat the filament, it also measures filament non stop so you know how much you have left (not very accurate but..) .. I ordered one from HK and loved it and now ordered another 10 😄 would be useful for kai's and bunch of other filaments, especially ugly ones like brittle 3mm natural pla or water loving nylon 😄 ( ) ... not very useful for real wet clay 😄 ...

    thanks for sharing the details, I was expecting you are using moineau pump to get that precise extrusion rates, piston+auger ... must be some precise machining 😄

  • @tom_lauerman Thanks for the lesson - very informative. You obviously know your subject. If I every decide to build a clay printer, and need answers, I'll know who to ask.☺

  • @smece Interesting about the filament boxes, I haven't seen those. I think preheating would really help with printing Kai's filament. Thanks for the link.

  • @deckingman Many thanks! I've been working with ceramics more or less full time for 20 years, so I've picked up a few things ☺ I'm going to revisit dual extrusion with a teeter-totter system (nozzle not in use moves up and out of the way) in the near future and a year or so ago this forum gave me some very good staring advice on that, much appreciated.

  • Hello, @tom_lauerman I would like to know what software you use to cut your STL's, since as I currently understand the prints are calculated from solid mm of filament and in your case you use clay, what parameters do you move or what is the configuration and how do you find it?

  • It's been 30 years or so that I've last tried to make something out of clay - but I remember very clearly being warned about trapped air bubbles, since they expand in the oven and may cause the hardened part to shatter (and damage parts around it). You appear to be using infill structures similar to "regular" 3D printing - how do you deal with that?

  • @jhonf441 Thanks for your interest, sorry for the slow reply, I hadn't seen your reply until just now. I use Slic3r, Prusa Slicer, or Cura to prepare the files for clay printing. I've made a printer configuration that works for my custom system. Because I am using a 50mm diameter tube of clay as "filament" I can input the diameter of the filament in the slicer as 50mm. Believe it or not, the slicers handle this just fine, doing the correct calculations to account for a 50mm filament being pushed through a 1mm or so nozzle.

    As for air pockets, one really just has to be sure the material is thoroughly dry and has heat added at an appropriate rate of increase. Rushing the firing or putting damp work in the kiln would be problematic. The concern is to not turn trapped water into steam, causing an explosion. Printing offers some advantages with this as it is possible to have very uniform wall thicknesses as well as very thin walls.

  • @tom_lauerman hello I would like to know more about the correct calculations to take into account that a 50 mm filament is pushed through a nozzle of approximately 1 mm, how is the calculation?

  • @jhonf441 Hello again, I maybe made that sound more complex than it is, here goes again:

    In my slicing program under filament diameter I use a value of 50mm.
    Also in the slicing program, I set the nozzle diameter for the printer to 1mm.

    The slicing program knows from these settings just the right rate of speed at which to advance the plunger through the syringe, because I have an extruder e-step value that is accurate. If I send a command to extrude 10mm the plunger moves downward 10mm.

    Many other tweaks can be made, such as "flow multiplier" in the slicer, or realtime extruder motor adjustments in the Duet web interface for fine tuning.

    The speed of the auger in my tool can be adjusted independently as well in the Duet web interface. However, the auger isn't really pulling the clay through the feed tube, just helping avoid lag or oozing.

    I hope that makes more sense.

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