My print fails here
Match what you see on the failed print (spaghetti, drooping, curling, snapped layers) to its cause, and fix it in the model rather than only in the slicer.
Follow along
L bracket example
A failed print is frustrating, but the failure usually points to a specific cause, and most causes can be fixed in the model. Find the symptom that matches yours below.
First, a 60-second diagnosis
- Note where it failed: at the bottom, at a certain height, or at a specific feature.
- Open Make, choose 3D Print (FDM) with your printer and material, and look at the heatmap. The hot spots often sit exactly where your print failed.
- Read the issues list for that area.
If the heatmap and the failure agree, you found the cause. If not, it may be a printer or material problem, such as a poor first layer, wet filament, or a clogged nozzle, and no model change will fix it.
Symptom guide
| What you see | Likely cause | Fix in the model |
|---|---|---|
| Drooping, messy underside on a shelf, arch or hole | Overhang past about 45 degrees | Add a 45 degree chamfer, make horizontal holes teardrop shaped, reorient the part |
| Spaghetti starting mid-print | Detached bottom, or a tall thin part that wobbled | Add a wider base, a brim, or print it laying down |
| Stringy or sagging flat span between two supports | Bridge too long | Shorten the span, add a column, or redesign as an arch |
| Corners lifting off the bed, or curling | Warping from cooling on large flat areas, especially ABS or ASA | Round corners (3 to 5 mm), add a brim, avoid huge flat bottoms, use PLA or PETG |
| Walls missing, gaps or ragged infill in thin areas | Wall thinner than two nozzle passes (0.8 mm) | Thicken to 1.2 mm or more, in multiples of 0.4 mm |
| Tiny details gone: text, small pins, fine ribs | Feature smaller than the nozzle can make | Enlarge the feature to 0.8 mm or more, strokes at least 1 mm for text |
| Holes too small or screws will not go in | Printed holes shrink | Make holes 0.1 to 0.2 mm larger, or use the clearance hole type |
| Layers split apart, part snaps along layer lines | Load acting across layers | Reorient so the load runs along layers, thicken the weak section, add a fillet |
| Supports fused to the part, impossible to remove | Dense supports against a fine surface | Redesign to avoid supports, or leave room for tools and use looser support settings in the slicer |
| Bottom edge flared, fits poorly | First-layer squish (elephant's foot) | Add a 0.4 to 0.6 mm chamfer on the bottom edge |
| Part does not fit the bed | Too big | Split it. See Split a part to fit your printer |
| Warped lid, flat part bows upward | Thin, wide, flat part cooling unevenly | Add ribs or a lip, or print it in a stiffer material |
Fix it with Solid Vibes
For each issue in the list, try Fix. Fixes are previewable. If you prefer to do it yourself, ask in plain terms:
The underside of the shelf drooped when I printed it. Add a 45 degree chamfer under the shelf so it prints without supports, and keep the shelf's top surface flat.
The text on the lid disappeared. Make the letters at least 1 mm stroke width and 0.6 mm tall, and tell me if the font is too small for a 0.4 mm nozzle.
The part snapped along the layers where the arm meets the base. Add a 5 mm fillet there, thicken the arm to 6 mm, and recommend an orientation where the layers run along the arm.
If you do not know the cause, describe the failure and let the agent reason about it:
My print failed at about 40 mm high, with the layers around the top of the cutout turning to spaghetti. Look at the model and tell me what is most likely going wrong, and how to redesign it.
Is it the model, or the printer?
| Clue | Probably |
|---|---|
| The failure is at the same feature every time | The model (design or orientation) |
| It fails at random places | The printer, filament or setup |
| It works in PLA but fails in ABS or ASA | Warping or temperature, not geometry |
| The first layer never sticks | Bed leveling, cleanliness or temperature |
| Stringing, blobs, rough surfaces | Slicer or filament settings |
| Parts are dimensionally off by the same amount | Printer calibration. See Parts don't fit |
How to avoid it next time
- Run the manufacturability check before you slice. It takes a minute.
- Set the right printer and material so the rules match your reality.
- Add a design intent rule such as "never a wall under 1.2 mm".
- Prefer chamfers to flat ceilings. They are free to print.
- Print a small test of any risky feature before the full part.
- Record what worked. Keep a note on the Thing about orientation and settings that succeeded.
Try it
On the L-bracket template:
I am going to print this in PETG on a Prusa MK4. Find every feature that could fail, rank them by risk, and fix the top two.
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