Flanges enable an all-in-one 3D printed block mold for slip casting

The center piece of this 3D printed assembly defines the outside shape of the ceramic vessel (plus two spares at the top). This entire assembly is an all-in-one case mold for a two-piece plaster working mold. This was printed as six light-weight units on standard Prusa MK3 and MK4 printers, walls are 0.8mm thickness. The upper and lower inside model halves were glued together (with the aid of an inside hoop to line them up). Outer flanges were glued on to enable clamping the outer shell vertically and horizontally.

The membranes defining mold mating points are printed onto the inside model, they extend out far enough to clamp between the flanges of the outer shell sections (suspending the model in the center). The membranes have holes to enable inserting natch-pairs. The thin base is glued on to hold the lower outer shells in place (in flexes enough to enable extracting the plaster form without mold breakage). The whole assembly is held together by clamps so it can be used multiple times.

Related Pictures

Fastest possible 3D print of a case mold part

I am 3D printing half of the bottom section of the outside shell assembly of an all-in-one case mold (to make a plaster mold for casting pottery). There are multiple factors to take into account to make this print quickly with minimum material and yet be strong.

Notice the green 3mm wide brim all around the base (in the slicer view top right). The slicer generates that when asked, it helps stick the part to the printer bed.
Flanges are present on all sides of these to enable clamping them together. The overall shape and flanges on a ready-to-pour assembly make for plenty of strength. However, the top, which is actually the down side when assembled, prints with no flange (so no printed support is needed). I print separate flanges (shown between the top and bottom pieces (on the left) and glue them on.
I design with 0.8mm thick walls, these thus print in two passes (see video). This piece prints in about an hour on my machine. It weighs only 36g.
If the flanges are not 0.8mm thick the printer makes separate motions there risking catching the edge and flexing the print on each pass (this eventually loosens it from the bed).

3D Printing an entire one-off case mold in one piece

This 3D printed shell encloses an entire two-piece mold for v 5.0 Medalta Potteries ball pitcher - all that is needed is to fill it with plaster and peel off the PLA casing after it sets. We are still in the development stages so the fact that this will only produce one mold is fine. The membrane across the center is where the two mold halves mate (it also holds the inner model in place). The membrane has holes where natch-pairs can be mated for embedding into the plaster mold. The spare (shown lower right) will be rotated 90 degrees, it has a slot that fits snuggly over the membrane to hold it in place. The handle is being done separately. This was printed on a consumer 3D printer with standard PLA filament.

What is the best 3D mechanical design software for ceramics in 2025?

This picture has its own page with more detail, click here to see it.

CAD software and 3D printing are a potential revolution in vessel mold-making for ceramics (3D modelling is another topic). But there are two big problems: There is no way a potter, hobbyist or even small manufacturer can afford the typical software cost. While it is true most have free or low-cost trial or hobby versions, the strings attached are deal breakers. The second problem is the complexity of learning - that can be a bigger obstacle than cost. Until the recent price increase Fusion 360 seemed to be exactly what was needed. A great way to on-board the CAD world, using the free version and its great learning resources and best-in-class user interface. It is new and modern, a YouTube star. It is fully parametric supporting constraints and a timeline. True, it can choke on more complex drawings on consumer computers, but we don’t need to do those. But, for commercial use, it costs $680/yr. But that is cheap compared to some others! Upon discovery of the capability, the cost might be doable for you. Here are the ones you likely cannot afford (and maybe don't want): -OnShape runs in your browser. It focuses on collaboration for teams. Free-version drawings are public but going private costs $1500/yr! -Rhino is usable for CAD but is polygonal and targeted at modelling. It is not fully parametric and does not have a traditional timeline (however Rhino+Grasshopper is life-changing for geeks, both for CAD and modelling). $1000 to buy but upgrading is $500+. -Solidworks is fully parametric with editable history. But it is old, the interface shows it. It is low cost for hobby use but for commercial use it is far out of reach for individuals ($2600/yr in 2025). Some upcoming possibilities: -FreeCAD is becoming more viable. It is parametric, has constraints and exports and imports popular formats (but with lots of issues). Its model tree is equivalent to the Fusion 360 timeline, but more clunky and depends on careful setting of constraints. The learning curve right now puts it out of practical reach of most. But a capital injection, like Blender got, is coming. -Shapr 3D costs $299/yr, also works on iPad (which Fusion 360 does not), and uses the Parasolid engine like OnShape and SolidWorks. But it seems to be targeted at being intuitive for conceptual modeling and quick prototyping for drawings that are finalized in other products (limited support for accurate feature placement, constraints, parametrics and boolean operations).

Links

Glossary	0.8mm thickness This is an ideal wall thickness to print on consumer 3D printer since to normally creates sufficient strength and prints in one two passes
Glossary	All-in-one case mold A method of 3D printing the case mold shell of an entire assembled plaster mold for using in ceramic production.
Glossary	Mold Shell Flange Learning to create flanges in CAD design enables a new kind of DIY mold-making for ceramics: 3D-printed lightweight reusable molds that clamp together.

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