Supports that will not come off or ruin the surface

Likely causes

In order: the most frequent cause comes first.

1. 01Support-to-part separation set too small in the slicer
2. 02A material with very good layer adhesion, such as PETG, that welds the support to the part
3. 03Support density too high
4. 04Supports generated with an unnecessarily conservative angle threshold
5. 05A part orientation that forces supports onto visible surfaces

How to fix it

Apply one fix at a time and reprint the same test part. Changing three settings at once tells you nothing about which one worked.

1. 01

   Increase the support-to-part gap

   Easy

   Raise the Z gap to around 0.2 mm on PLA and 0.25–0.3 mm on PETG, and the XY gap to 0.5 mm. You gain easy removal at the cost of a little quality on the supported face, which was going to be marked anyway.

2. 02

   Switch to tree supports and lower the density

   Easy

   Tree supports touch far less surface and come away almost on their own. Also drop the density to 10–15 %: a support does not need to be solid, it only has to hold the material while it cools.

3. 03

   Use a support interface in a different material

   Hard

   If you have a multi-material system, print the interface layer in a material that will not bond to the part's, or in a soluble one outright. Prusa notes HIPS works as support for PETG, ABS and ASA because it dissolves in limonene, and that PVA or BVOH work for PLA and PETG in water.

4. 04

   Reorient the part so it needs fewer supports

   Easy

   Before fighting with settings, try another orientation. Many parts that look like they need support across a whole face stop needing it when rotated 45 degrees, and the visible face stays untouched.

How to prevent it

• —Tune and save the support gap per material in your profile
• —Default to tree supports unless the geometry demands otherwise
• —Orient the part so visible faces point upward
• —Reserve soluble support for geometry that genuinely has no alternative

Sources

1. [1]Failing supports | Prusa Knowledge BasePrusa Research · Manufacturer · accessed July 27, 2026
2. [2]Bad looking surface above supports | Prusa Knowledge BasePrusa Research · Manufacturer · accessed July 27, 2026
3. [3]HIPS | Prusa Knowledge BasePrusa Research · Manufacturer · accessed July 27, 2026