QuicklayerPrints

Design for printing.

The handful of numbers that decide whether a part prints well. They’re the rules we check every file against, so following them means fewer surprises and a quicker yes.

Quick reference

Filament (FDM)Resin
Minimum wall1.2 mm · 2 mm if it carries a load0.8 mm
Raised or cut-in detail0.6 mm high or deep, 0.8 mm wide0.3 mm
Smallest readable text4 mm tall, bold sans-serif2.5 mm tall
Sliding fit0.3–0.4 mm gap per side0.15–0.2 mm
Press fit0.1 mm per side0.05 mm
Unsupported overhangup to 45° from verticalalways supported
Unsupported bridgeup to 20 mm—
Largest single part252 × 252 × 254 mm—

01 Wall thickness

Cross-section of a printed wall: three extrusion lines side by side make a 1.2 mm wall 1.2 mm = 3 lines A solid partThe wall, magnified 0.45 mm line
Our filament printers lay down lines 0.45 mm wide, so a 1.2 mm wall is three lines side by side.

A filament printer builds every wall from lines of melted plastic about 0.45 mm wide. Anything thinner than two lines is either skipped by the slicer or printed as a single fragile line, so 1.2 mm is our minimum. Anything that holds weight, clips shut or gets handled a lot should be 2 mm or more.

Resin can go down to 0.8 mm. If you hollow a resin model to save material, add two drain holes at least 3 mm across so uncured resin can escape; trapped resin cracks parts weeks later.

02 Tolerances & clearances

A peg in a hole with a clearance gap on each side 0.3–0.4 mm each side to slide holepeg
Leave a gap on each side, not in total.

Printed parts come out within about ±0.2 mm on filament and ±0.1 mm on resin. When two parts fit together, design the gap in:

  • Sliding or turning fit (a lid, a hinge pin): 0.3–0.4 mm per side.
  • Snug fit that goes together by hand: 0.2 mm per side.
  • Press fit that needs a squeeze or a tap: 0.1 mm per side.
  • Print-in-place hinges and chains: 0.4–0.5 mm, and tell us so we don’t “fix” it.

03 Overhangs & bridges

Overhangs: 45 degrees prints unsupported, steeper needs support; a chamfer instead of a flat ceiling 45° prints fine flat ceiling: support add a chamfer
Each layer can sit about halfway off the one below. Past 45°, it needs something underneath.

Each layer needs something to sit on. Slopes up to 45° from vertical print cleanly; steeper than that, and flat ceilings, need temporary supports that we remove by hand, which leaves a rougher surface and adds time.

Swap a flat underside for a 45° chamfer where you can, and make horizontal holes teardrop-shaped (a point at the top). A flat span between two supports (a bridge) is fine up to about 20 mm.

04 Text & fine detail

Embossed and engraved lettering with minimum sizes embossed ≥ 0.6 mm engraved ≥ 0.6 mm deep stroke ≥ 0.8 mm widetext ≥ 4 mm tall
Text reads best on top faces. On sides, it takes on the layer lines.

Use a bold sans-serif at 4 mm tall or more, with strokes at least 0.8 mm wide. Raised text should stand at least 0.6 mm proud; cut-in text should go at least 0.6 mm deep. Fine serifs and script fonts fill in on filament: if the lettering matters, choose resin, where 2.5 mm text is sharp.

05 Holes, pins & threads

Holes print about 0.2 mm smaller than drawn, because the plastic squashes inwards. Either draw them 0.2 mm larger or tell us the size that matters and we’ll drill or ream them to size.

Printed threads work from about M8 upwards. For smaller screws, draw a plain hole and tell us the thread: we fit brass heat-set inserts, which are far stronger than printed threads and survive being undone again and again.

Pins thinner than 3 mm snap easily on filament. Where a pin must be small, print it lying down, or use a steel pin in a printed hole.

06 Strength & orientation

Layer direction decides strength: a hook printed lying down is stronger than one printed standing up standing: snaps lying down: strong
Layers bond to each other less strongly than a line bonds to itself.

A filament print is strongest along its layers and weakest between them, a bit like wood with the grain. A hook printed standing up snaps along a layer line; the same hook printed on its side is several times stronger. When we check your file we choose the orientation for strength first and looks second, unless you tell us otherwise.

Round off inside corners with a fillet of at least 1 mm: sharp inside corners are where cracks start.

07 Splitting large parts

A large part split in two with alignment pins flat joint + 4 mm pinspart Apart B
Split along a flat face so both halves print flat on the bed, and add pins so they only go together one way.

Our largest filament printer, P1S 1, takes parts up to 252 × 252 × 254 mm. Bigger things are printed in pieces and joined. The best splits:

  • run along a flat face, so each piece prints lying on that face;
  • sit where a seam looks deliberate: an edge, a groove, a change of colour;
  • include two 4 mm alignment pins with 0.2 mm clearance, or a tongue and groove;
  • join with glue for decorative parts, or bolts through printed bosses for anything that takes load.

If you’d rather not do it yourself, send the whole model: we’ll suggest where to cut and show you before we print.

08 Before you export

  • It’s a closed solid, with no holes in the surface.
  • Walls are at least 1.2 mm (0.8 mm for resin).
  • Parts that fit together have clearance designed in.
  • It’s drawn in millimetres, or you’ll tell us the units.
  • Fine detail is on top faces, and at least 0.6 mm high or deep.
  • It fits one of our printers, or it’s split with pins.
  • You’ve exported STL, 3MF or OBJ at a sensible resolution (under 50 MB).
Check your model Exporting a clean file