Most print failures trace back to the file, not the printer. This guide covers the critical checks — wall thickness, manifold geometry, supports, and tolerances — that separate a clean print from a failed one.
FDM printers extrude plastic in lines ~0.4–0.6mm wide. A wall needs at least 2 extrusion widths to be structurally sound. Walls thinner than 0.8mm may be ignored by the slicer entirely.
| Use Case | Minimum | Recommended |
|---|---|---|
| Decorative / visual only | 0.8mm | 1.2mm |
| Structural / load-bearing | 1.2mm | 2.0–3.0mm |
| Snap-fit clips | 1.5mm | 2.0mm |
| Threaded features | 2.0mm | 3.0mm+ |
| Flexible parts (TPU) | 1.0mm | 1.5mm |
A manifold mesh has no holes, no duplicate faces, and no edges shared by more than two faces. Slicers determine "inside" vs "outside" mathematically — a non-manifold mesh breaks this calculation and produces slicing errors.
Common causes: Boolean operations leaving internal faces, imported geometry from different CAD programs, sculpting software exports without cleanup, or overlapping bodies.
How to fix: Upload to Microsoft 3D Builder (free, Windows) or Meshmixer (free) and use the auto-repair function. We also perform a compatibility check on every file and flag issues before printing.
FDM prints layer by layer from the bottom up. Any surface extending beyond 45° from vertical needs support structure beneath it or a redesigned orientation.
Design strategies to reduce supports:
Include a note in your quote request if you have specific finish requirements on overhang surfaces — we can adjust support settings accordingly.
FDM printing has a typical dimensional accuracy of ±0.2mm. Parts intended to fit together must account for this.
| Fit Type | Clearance Per Side | Example |
|---|---|---|
| Press fit (tight) | 0.1–0.2mm | Pin in hole, bearing seat |
| Snug / hand fit | 0.2–0.3mm | Lid on box, removable cap |
| Loose / sliding | 0.4–0.6mm | Drawer slider, guide rail |
| Clearance (free movement) | 0.6–1.0mm | Hinge pin, bolt through hole |
Always export your STL in millimeters. STL files do not store unit information — if you model in inches and export without converting, the part will be 25.4x too small.
Quick sanity check: a standard AA battery is 50.5mm tall × 14.5mm diameter. A credit card is 85.6mm × 54mm. Use known objects as reference in your CAD view.
| Format | Extension | Best For |
|---|---|---|
| STL | .stl | Universal — compatible with all CAD and modeling software |
| 3MF | .3mf | Modern format — preserves color, scale, and orientation data |
| OBJ | .obj | Texture and color data from sculpting software |
| STEP | .step / .stp | CAD-precise geometry for engineering parts with tight tolerances |
Maximum file size: 256MB. We run an automatic compatibility check on every uploaded file.
1.2mm for structural parts and 0.8mm for non-structural walls. Thinner walls may print but will be fragile. For functional parts under stress, 2–3mm walls are recommended.
A manifold mesh is watertight — every edge is shared by exactly two faces with no holes or gaps. Microsoft 3D Builder and Meshmixer can automatically repair most non-manifold geometry.
FDM has a typical dimensional tolerance of ±0.2mm. Design 0.2–0.4mm clearance per side for snug fits, and 0.4–0.6mm for sliding fits.
The most common causes are non-manifold geometry (invisible in modeling software but flagged by slicers), walls that are too thin, incorrect units (modeling in inches but exporting as millimeters), or geometry that is technically valid but physically unprintable.
We check every file for compatibility and flag issues before printing begins.
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