Materials, tolerances and design rules
Everything you need to pick a material and design a part that prints well the first time.
Which of the three do you want?
| Property | PLA | PETG | ABS |
|---|---|---|---|
| Best for | Fit checks, appearance models, indoor jigs | Functional parts, enclosures, anything damp | Heat, impact, outdoor and automotive |
| Heat resistance | ~55 °C | ~75 °C | ~95 °C |
| Stiffness | Highest | Medium | Medium |
| Toughness | Brittle | Tough | Tough, slightly soft |
| Surface finish | Best | Good, slight gloss | Good, matte |
| Dimensional accuracy | Best | Good | Good, more shrinkage |
| UV / outdoor | Poor | Fair | Fair, better painted |
| Glues & paints | Fair | Fair | Excellent (solvent welds) |
| Machinable after | Chips | Fair | Best |
| Material cost | $28/kg | $34/kg | $36/kg |
| Relative part price | Base | +10% | +18% |
Not sure? Pick PETG. It is the right answer for most functional parts, and it is what we would choose ourselves if you handed us the part and walked away.
What we can actually hold
- General dimensional tolerance
- ±0.3 mm or ±0.3%
- Layer heights available
- 0.12 / 0.20 / 0.28 mm
- Minimum wall thickness
- 1.2 mm (0.8 mm cosmetic)
- Minimum embossed detail
- 0.6 mm wide, 0.4 mm tall
- Holes print undersize by
- ~0.2 mm (we can ream)
- Maximum build size
- 250 × 250 × 250 mm
- Unsupported overhang
- Up to 45° from vertical
- Bridging span
- Up to ~30 mm
Whichever is larger applies: a 10 mm feature gets ±0.3 mm, a 300 mm feature gets ±0.9 mm. If one dimension is critical, tell us which and we will orient the part around it or machine it afterwards.
Ten rules that prevent nine out of ten problems
- Keep walls at or above 1.2 mm. Thinner prints, but it will not survive being handled.
- Add fillets to inside corners. Sharp internal corners are stress risers and the first place a part cracks.
- Design holes slightly oversize, or tell us which ones matter so we ream them to size.
- Use heat-set inserts for threads that will be undone more than a few times. Printed threads work, once.
- Orient load along the layers, not across them. FDM parts are weakest between layers — we will orient for strength if you tell us the load direction.
- Avoid overhangs beyond 45° where you can. Supports leave marks and cost labour to remove.
- Chamfer the bottom edge 0.5 mm to avoid the small lip the first layer leaves behind.
- Leave 0.2–0.3 mm of clearance between parts that must fit together, more for sliding fits.
- Tell us which face is cosmetic. We will put the supports on the other one.
- Split parts bigger than the build envelope on a flat seam, or let us do it — bonded ABS joints are genuinely strong.
What the options in the quoting tool actually change
Layer height
The thickness of each printed layer. Fine layers look better on curves and take noticeably longer; draft layers are quick and strong but show the steps.
- 0.12 mm
- Detail, slow
- 0.20 mm
- Our default
- 0.28 mm
- Fast, robust
Infill
How solid the inside is. It affects weight, strength and price. Going past 60% rarely buys much strength — extra walls do more.
- 15%
- Cosmetic
- 20%
- Standard
- 40–60%
- Load bearing
- 100%
- Tooling, bosses
Finish
How much hand-work goes into the part after it comes off the bed.
- Standard
- Supports off
- Cleaned
- Trimmed, deburred
Still deciding? Quote it three ways.
Upload your STL once and switch materials in the quoting tool — the price updates instantly, so you can see exactly what ABS costs over PLA before you commit.
Compare on my own part