How to prepare an STL file for 3D printing: a pre-order checklist

1. Format: STL, 3MF or OBJ

Printing needs a polygon mesh, not a drawing. STL is the standard every program and library exports. 3MF is better: it stores units, colors and print settings and weighs less. OBJ works if there are no textures. STEP and IGES are CAD formats — we convert them ourselves, but the calculator does not read them: send such a file on Telegram.

2. Units: millimeters, not inches

STL has no units, so a model from a US library can open 25 times too small or too big. Easy check: the calculator shows the dimensions right after upload. If a phone case comes out 7 × 3 mm, the file is in inches — type the real size into the “height” field and everything recalculates.

3. A watertight mesh with no holes

The slicer cuts the model into layers and must know what is “inside”. A hole or flipped faces make the weight wrong and leave gaps in the print. Free check: Bambu Studio offers to repair the mesh on import; online, 3D Builder on Windows or the Formware service do it. We run every file through mesh repair before printing and tell you if the model had to be changed.

4. Wall thickness: 1.2 mm and up

• A 0.4 mm nozzle prints walls in whole lines: 0.8, 1.2, 1.6 mm. A 1.0 mm wall becomes 0.8 mm plus a gap.
• Minimum for decor — 1.2 mm; for load-bearing parts — 2 mm or more.
• Small text and relief: no thinner than 0.8 mm and no lower than 0.4 mm, or it blurs.
• Holes print slightly smaller than nominal: for an M5 bolt design 5.3–5.5 mm.

5. Orientation: which side is the bottom

The printer builds bottom-up, and anything overhanging steeper than 45° needs supports — extra plastic, time and marks on the surface. Rule: largest flat face down, pretty side up or sideways. A case prints open side up, a vase bottom down, a figurine on its feet or back. Our calculator counts supports in the orientation the model has in the file, so a good position shows up immediately in the weight.

6. Size: up to 250 mm in one piece

The Bambu Lab P2S chamber is 250 × 250 × 250 mm. Larger models are printed in parts and glued, but it is better to design the cut into the file: along a flat face, with a key or pins. If a cut is not needed, consider scale: a part half the size weighs eight times less and costs roughly five times less.

7. Several parts: one per file

A set of ten parts is easier to send as ten files or one 3MF with separate objects. Then we arrange them on the bed optimally and you can order different quantities. A single STL where parts are merged into one object cannot be split by the slicer.

8. What else to tell us in the order

• What the part does: bears load, sits in the sun, touches food — this decides material and infill.
• Fit tolerance: if the part must slide into another, send a photo or the size of the mating part.
• Color and quantity — the calculator asks for these.
• Deadline: if you need it by a date, say so and we plan the queue.

The short checklist

• STL, 3MF or OBJ up to 100 MB, in millimeters.
• Mesh closed, normals facing out.
• Walls from 1.2 mm, text from 0.8 mm.
• Flat face down, minimum overhangs.
• Up to 250 mm per side, or the cut is designed in.
• Set parts as separate objects.

FAQ