Model the raft into the part instead of trusting the slicer
Slicer rafts are inconsistent from machine to machine and often peel or leave a mess. If you need a raft, draw it into the CAD so the same file prints the same way everywhere.
Applies to
- Process
- FDM / filament
- When
- Bed adhesion / first-layer protection on warp-prone parts
- Materials
- Especially high-warp plastics like ABS
Why it matters
Slicer rafts are ambiguous and machine-dependent — layer counts, spacing and cooling all differ between setups, so a part you prototyped can behave differently at a print farm or through a blind API/service. Modeling the raft into CAD makes the result travel with the file.
The default ring-shaped raft pattern is one fat bead of plastic; in high-warp material that thick bead shrinks and peels the raft off the bed. A thin modeled plate you control avoids that, keeps the part cinched down, and doesn’t leave stringy residue on the part.
What good looks like
- The raft is a thin plate visible in CAD, not a slicer setting
- It sits about one layer height below the part so it still adheres but releases
- Outer edges are rounded/filleted (a disc is ideal) so no sharp corner warps on the first layer
How to apply it
- Fillet the vertical edges of the part first — no sharp corners on the first layer.
- Model a thin plate under the part, spaced by roughly your layer height (≈ 0.2 mm at a 0.2 mm layer; less to increase adhesion).
- Round the raft’s outer edges — a circular outline avoids warp-prone corners.
- Print with slicer rafts OFF and confirm the part stays cinched down and releases clean.
Modeling a thin, rounded raft plate ~1 layer height below the part instead of using slicer rafts — Design Rafts in CAD | Stop Using Slicer Settings ↗.
Summarized and independently edited by Start Here. Starting values and cautions are our editorial notes, not a quotation from the creator.