Routing / CNC to form ceramic work?

[moh]

Hi folks,
Posting this to see if anyone has done something as ridiculous as using a router / CNC to form their ceramic piece
I've been playing around with a design that's a 4"x6" (3.5" thick) solid piece of clay that's basically an O with very crisp edges. Can't extrude it, can't slipcast it since it's a solid slab of thick clay. 
So now I'm thinking to ram press the piece, let it dry and use a router on it for that sharp crisp edges. Has anyone looked to power tools to sculpt their piece this way? Care to share your experience?

[Hulk]

Hi moh!

No experience machining clay, am recalling a thread here (this forum) on turning pieces using a lathe (not recalling if it was a wood or machine shop model); any road, bein' curious (and on the couch), found

a five axis cnc milling machine (by Tarus), aye.

Note the work is being done on damp clay panels, hence chips (vs. dust), which makes some sense, eh?

Whilst waiting on replies, could you expand on the three and a half inch thick idea?

[neilestrick]

Does it have to be solid? Lots of potential problems with drying and firing something that thick. Casting it hollow would save a lot of headaches.

Clay is terribly abrasive, so it'll dull tools quickly, and the dust can wreak havoc on machinery. Even working leather hard you'll need to deal with dust and clay bits getting into the moving parts.

Seems like with something that small you could do it by hand. Or make a model via CNC, then make a mold of it and slip cast or press mold it. You can cast solid things, there's just not a lot of good reasons to do so.

[moh]

Yes I did think about making it by hand, the trouble is that this project is for 3000 of these. omg..

[neilestrick]

5 hours ago, moh said:

Yes I did think about making it by hand, the trouble is that this project is for 3000 of these. omg..

I would definitely think about making a few masters via CNC, then making a bunch of plaster molds and slip casting them hollow, assuming they don't need to be solid for some reason. You can probably get 3 casts a day, so with 10 molds you're done in 100 days.....Plus you'll save a lot of clay by making them hollow, and save a ton of weight if you need to transport the bunch. I think the mess of dealing with CNCing 3000 clay pieces would be horrendous. Alternatively, you can make a press mold. Regardless of the method, you're probably looking at a certain amount of hand work before they're done, whether it's prepping the piece for machining, or cleaning up joints after molding. If you're just looking for the finished product, there are ceramic production services that may be worth the money. They could also just make the molds for you if that's not something you're adept at. Mudshark Studios is one company that comes to mind. 

[PeterH]

Sadly the car industry seems to use CNC on oil-clay rather than fire-able clay.
Why car designers stick with clay http://www.bbc.com/autos/story/20161111-why-car-designers-stick-with-clay
The first thing to know about this marvelous medium is that it isn’t actually clay. “Clay is different waxes with some filler in it,” says VandenBrink. “That used to be sulfur, and more recently small glass beads, but it’s mostly waxes. Honestly, it’s hard to know exactly what’s in it, because the formulas are proprietary.” There are half a dozen companies that make plasticine clay suitable for full-scale design modelling (a few car companies make their own blends), and they deliver their product to design shops on flatbed trucks by the pallet-load. In a typical year, Ford goes through about 100 tons of the stuff, formed into hard, extruded cylinders about 3 inches in diameter. When a designer is ready to build, a lump of it is heated to about 66°C (150°F), and applied.
... still it's pretty to watch, and I include a video as eye-candy.

Slipcasting does seem an attractive option, but I wonder how difficult it will be to handle the shrinking onto the core forming the hole in the "O"? Sounds like the sides might be deep, crisp and vertical. Are you glazing or going for an unglazed vitreous surface? 

 CNC eye-candy:

 

[Magnolia Mud Research]

On 3/16/2021 at 3:39 AM, moh said:

Posting this to see if anyone has done something as ridiculous as using a router / CNC to form their ceramic piece
I've been playing around with a design that's a 4"x6" (3.5" thick) solid piece of clay that's basically an O with very crisp edges. Can't extrude it, can't slipcast it since it's a solid slab of thick clay. 
So now I'm thinking to ram press the piece, let it dry and use a router on it for that sharp crisp edges. Has anyone looked to power tools to sculpt their piece this way? Care to share your experience?

Consider this analogy for your project: make bolt washers from pipe instead of bars. 

Devise an pipe extrusion setup for long lengths of clay pipe: Say 2-3 meter. When the "pipe" is at ~bone dry, slice the pipe on a fine bladed bandsaw into sections to fit the specification.  

Must first determine the intermediate dimensions (for extrusion and for the bone dry states) that meets the required fired dimensions.  You might find that you can cut cleaner at a moisture level between leather hard and fully "bone dry".  I have found in some of my work that sawing of not-fully-bone-dry clay leaves a smoother cut surface than at bone dry.  Experiment.   

LT