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Designing for sand 3D printing: size, walls and files
Six numbers make a file printable in sand: walls of 5 mm or more, overhangs 7 mm thick reaching up to 50 mm, holes from 3 mm, two 30 mm escape holes for any closed hollow, 3 mm fillets on inside corners and detail from 1 mm. One print fills 1800 × 1000 × 700 mm. Send STEP, OBJ, STL or 3DM.
Sand 3D printing is forgiving. The loose sand around a piece supports it while it prints, so there are no support structures to remove and almost any form is possible. A few rules still decide whether a file prints as drawn. Keep to these six numbers and it will. Go under them and a piece can still work: we look at it with you in design review.
The six numbers
| Rule | Number | Why |
|---|---|---|
| Walls | 5 mm or thicker | Thinner than that, we look at it with you |
| Overhangs | 7 mm thick, out to 50 mm | An overhang this thick can reach up to 50 mm on its own |
| Holes | 3 mm and up | Holes this size stay open, so the loose sand can be cleared |
| Escape holes | 2 × 30 mm for any closed hollow | The loose sand inside needs a way out |
| Fillets | 3 mm radius on inside corners | A sharp inside corner is where a piece chips |
| Emboss and deboss | 1 mm | Lines, letters and texture read from 1 mm, raised or cut in |
Size
One print fills 1800 × 1000 × 700 mm. That is the footprint of a dining table, so tables, consoles, benches and lounge chairs can print in one piece. A piece can be turned on its side to fit. Anything larger is printed in parts and bonded.
Loose sand holds pieces at every height, so one print can carry a main piece and fill the space around it with smaller ones. That matters for a series or a whole interior: several pieces share one print.
Hollow or solid
Pieces print solid all the way through unless you design them hollow. Hollow is worth it. Price follows weight, so a hollow piece costs a fraction of a solid one that looks the same from outside. A 500 mm sphere weighs about 111 kg solid and about 45 kg with a 40 mm wall.
A closed hollow needs two openings of at least 30 mm so the loose sand can come out. Place them where they won't show, such as the underside. We plan them with you.
Built in, not added
Draw these into the file and they print with the piece:
- Joints. Pegs, sockets and lids. Press fit, sliding or loose: we set the gap with you in review.
- Cable channels. A clean path through solid sand for lighting, end to end. No drilling.
- Fixing points. A seat for a pin, so a wall piece hangs true.
- Cages. Delicate parts print inside a cage that holds them safe, cut away after.
Second materials
Sand sits well with glass, metal, wood, stone and light. Design the interface into the sand part: a rebate for a glass top, a channel for a cable, a seat for a clock movement. The second material is made to your brief and fitted before the piece ships.
Files we accept
- 3D files: STEP, OBJ, STL or 3DM (Rhino).
- No 3D file yet: a sketch with dimensions, or an image and a brief.
Before anything prints, we check four things that look fine on screen and go wrong in sand:
- Overlaps. Two shells that overlap are merged into one solid.
- Resolution. Too coarse a mesh prints curves as facets. We check it is fine enough for the size.
- Units. A file in inches or centimetres can arrive ten times too small. We check the size you meant.
- Loose parts. A part that touches nothing falls off in the sand. We find it before the print.
What sand is not made for
Small mechanical parts, mirror-polished surfaces and very thin walls. For those, another process will serve you better.
From file to piece
- File check and design review
- Print in black sand
- Lift out and clean
- Infiltrate with resin
- Finish by hand
- Crate and ship
Most pieces take 4-6 weeks. Pricing is by weight: €158 per kilogram including VAT, with no setup fees. See How much does sand 3D printing cost?
Ready to send a file? Start on Production.
Questions
What is the minimum wall thickness for sand 3D printing?
5 mm. Thinner walls are possible in some places, and we review them with you.
Do sand 3D prints need supports?
No. The loose sand around the piece supports it while it prints. Overhangs 7 mm thick can reach up to 50 mm on their own.
What is the largest piece you can print?
1800 × 1000 × 700 mm in one print. Larger pieces print in parts and are bonded.
Which file formats do you accept?
STEP, OBJ, STL or 3DM. A sketch with dimensions works too.
Can I print a hollow piece?
Yes, and it costs less. A closed hollow needs two openings of at least 30 mm so the loose sand can come out.
Is there a minimum order?
No. A single piece or a full series.
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