Supports that fall over, break or won't come off

Symptom

Supports come away from the bed, bend or break during the print, and the area they held comes out badly or collapses. Or the opposite: they are fused so tightly to the part that they are hard to remove and the face they touched looks ugly.

Likely causes, from most to least likely

1. Thin or sparse supports, not stable enough for their height.
2. Small support contact area on the bed.
3. Speed too high for such thin structures.
4. Contact (Z) distance to the part too small, very dense interface or very strong pattern: they come out fused.
5. Horizontal (XY) separation between support and part too small, fusing them to the walls.

Checks to tell which one it is

• Note when it fails: if they come loose in the first layers, it is adhesion; if they fall higher up, it is stability.
• Pay attention to the slicer's stability warnings.
• Check the top contact distance, interface layers, pattern and XY separation in the profile.

Before you start

Before taking anything apart, cleaning or adjusting it, switch the printer off and unplug it, unless a step says otherwise, and do not touch the nozzle, the heater block or the bed until they have cooled down. If in any doubt about electricity, heat or moving parts, stop and ask a professional.

Step-by-step fix

1. Add a brim to the supports

   Enable the brim for supports too, so they hold on to the bed better.

   Check: Supports don't come loose in the first layers.

   If that does not fix it: Make them sturdier.

2. Make them sturdier

   Reduce the pattern spacing on grid or snug supports, or increase branch density on organic ones. Honeycomb is the strongest pattern but the hardest to remove; rectilinear is the easiest to remove.

   Check: Supports reach the top in one piece.

   If that does not fix it: Print them slower.

3. Print them slower

   Lower the print speed for supports.

   Check: Supports don't bend or break.

   If that does not fix it: Reorient or split the part (last step).

4. Make them easier to remove

   Adjust the top contact distance: according to Prusa, 50-75% of the layer height usually works. Increase the XY separation if they fuse to the walls. Organic supports come off easily and barely mark the surface.

   Check: Supports come away by hand without tearing pieces off the part.

   If that does not fix it: Improve the face resting on the supports.

5. Improve the face resting on the supports

   If that face looks ugly, reduce the contact distance and pattern spacing slightly, or use 3-4 interface layers (Prusa's guideline). Bear in mind that the closer they are, the harder they are to remove.

   Check: The supported face is smoother and the supports still come off.

   If that does not fix it: Reorient or split the part.

6. Reorient, split or place supports only where needed

   Rotate or cut the model to reduce overhangs and use support enforcers and blockers to place supports only where they are needed. On multi-material printers, a soluble or breakaway interface makes them easier to remove.

   Check: Fewer supports, and easier to remove.

   If that does not fix it: Check the manufacturer's profiles for that material and support type.

Prevention

• Check the support preview before printing.
• Orient parts so they need as few supports as possible.

Still not fixed?

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Printers it applies to

Any FDM (filament) 3D printer, from any brand.

Official sources

This guide summarises the official documentation linked here:

• Failing supports · Prusa Research
• Support material · Prusa Research
• Bad looking surface above supports · Prusa Research