Process comparison · Process and manufacturing decisions
FDM or SLS: which process fits the part?
Both processes make functional polymer parts, but their process logic differs. FDM builds extruded roads and needs supports for some geometries. SLS uses a powder bed surrounding parts during the build.
In brief
FDM is often strong for one-offs, large parts or material-specific functional designs. SLS is often strong for complex support-free geometry and dense build packing. The actual quote decides.
Geometry
Shape determines support demand, orientation and finishing.
- FDM
- Supports on critical overhangs; large parts and targeted internal structure possible
- SLS
- Powder supports geometry; complex internal and nested forms possible
Properties and surface
Datasheets are comparable only when material, specimen and process are considered.
- FDM shows pronounced direction dependence from layers and roads.
- SLS surfaces are typically grainy; FDM shows visible roads and layers.
- Functional faces may need finishing in either process.
Procurement decision
Compare not only unit price but also samples, change risk and inspection effort.
- Quote identical CAD data with identical scope.
- State surface, colour and finishing separately.
- For production, inspect a representative sample in the target process.