3D Printing Supports: When You Need Them and How to Remove Them

3D printing supports are temporary structures that hold up parts of a model that would otherwise print in mid-air. This guide explains when supports are needed, how the main styles differ, how to reduce them and how to remove them safely. The information comes from Prusa and OrcaSlicer documentation and is not based on our own printing, so treat every setting as a starting point.

When do you need supports?

Prusa's knowledge base explains it simply: a 3D printer builds an object layer over layer, and each new layer must be supported by the one beneath. If part of a model starts in mid-air with nothing below, an extra support structure is needed for a successful print.

Small overhangs and bridges often print without help. How far a slope can go before it needs support depends on the layer height and the cooling, among other things, and slicers use a threshold angle. PrusaSlicer describes its overhang threshold as the most horizontal slope, measured from the horizontal plane, that can print without support (90 is vertical). A lower value generates less support. See layer height explained for how layers affect overhangs, and fixing poor bridging for spans.

How can you reduce the need for supports?

Prusa advises considering a different orientation or splitting the model into several parts, which can reduce overhangs and the number of supports generated. Other options from the documentation:

• Supports on build plate only stops supports growing from the model's own surfaces, so you avoid small blemishes where they touch.
• Support blockers and enforcers let you remove supports from places the automatic algorithm filled unnecessarily, or add them to only the places that need them.
• Paint-on supports in PrusaSlicer let you mark areas directly.
• A support enforcer in the middle of a long bridge can split it into shorter bridges, according to Prusa.

Our sagging overhangs guide covers what happens when an overhang is left unsupported.

What are the support styles?

OrcaSlicer also lets you choose automatic or manual placement, and offers a "critical regions only" option that supports only sharp tails and cantilevers. Menu names vary between slicers; OrcaSlicer for beginners, PrusaSlicer for beginners and Cura for beginners show where to look.

Support settings that matter

• Top contact Z distance: the vertical gap between the object and the support interface. Prusa notes that setting it to 0 is how support layers are kept synchronized with the object layers when a wipe tower is used.
• Raft: raises the object by a number of layers with support material generated underneath, and you peel it away afterwards. Related options are covered in brim vs raft vs skirt.
• Enforce support for the first layers: adds adhesion for objects with a thin or poor footprint.
• Soluble or breakaway supports: used with multi-material setups, with extra synchronization rules around a wipe tower in PrusaSlicer.

How do you remove supports?

Prusa says that, depending on the geometry and material, supports are often easy to remove with bare hands. Pliers help in hard-to-reach places, and a scalpel or utility knife can cut away stubborn pieces. It also warns that pieces of support can be surprisingly sharp and sometimes eject violently in a random direction, so consider protective glasses when removing hard supports.

Leftover marks and bumps are common; see fixing blobs and zits for surface blemishes.