Whether a printed part comes out strong, accurate, and clean depends on choices made in CAD. These are the starting rules we use for filament parts.
Wall thickness
- Minimum wall: at least 1.2 mm for a structural wall, and never below about 0.8 mm.
Overhangs and support
- Angles up to about 45 degrees from vertical print without support.
- Design support out where you can: add a chamfer under a horizontal boss, use a 45-degree fillet instead of a flat overhang, split the part, or reorient it.
Holes, bosses, and threads
- Add a small chamfer at the hole entrance to help fasteners start.
- Upright pins under about 5 mm diameter: add a radius at the base, lay the pin down in the print, or model a hole and press in a metal dowel pin. Fillet the base of every boss.
- Use heat-set brass inserts for anything that will be assembled and disassembled. Model a straight-walled hole to the insert manufacturer's spec.
- For coarse, low-stress threads (a jar lid, a knob), model them at 1.5 mm pitch or larger and test-fit.
Tolerances and fit
- Design clearance into mating parts. As a starting point, 0.2 mm for a loose slip fit, 0.1 mm for a snug fit, 0.3 to 0.5 mm for parts that must move freely. Printed parts vary with material and shape, so adjust from a test print.
Fillets and text
- Fillet inside corners, 1 to 2 mm.
- Raised text prints better than recessed text. Keep it at least 0.5 mm tall and 0.8 mm wide in the stroke.
Assemblies
- Split and join with dowel pins, snap-fits, or adhesive.
Send us the file
If the design itself needs work, ask for a design quote. Get a Quote or ask a design question.