3D Printing Design Guidelines
Design rules for SLS, MJF, FDM, SLA and DMLS: wall thickness, tolerances, overhangs, clearances and feature sizes, with a full guide for each process.
Design guides
Design for additive manufacturing
Each process has its own limits and freedoms. Compare the key design numbers, then open the full guide for the technology you are designing for.
thermoplastic
Selective Laser Sintering (SLS)
3D Printing for Complex Geometries & Functional Parts
- Min. wall
- 0.8–1.0 mm
- Tolerance
- ±0.3% (min ±0.3 mm)
- Layer height
- 0.06–0.12 mm
- Build volume
- 340 × 340 × 600 mm
thermoplastic
Multi-Jet Fusion (MJF)
3D Printing for High-Performance Prototypes & End-Use Parts
- Min. wall
- 1.0 mm
- Tolerance
- ±0.3% (min ±0.5 mm)
- Layer height
- 0.1 mm
- Build volume
- 380 × 284 × 380 mm
thermoplastic
Fused Deposition Modeling (FDM)
3D Printing for Functional Prototypes & Large Parts
- Min. wall
- 1.0 mm
- Tolerance
- ±0.25 mm or ±0.3%, whichever is greater
- Layer height
- 0.127–0.33 mm
- Build volume
- 914 × 609 × 914 mm
resin
Stereolithography (SLA)
3D Printing for High-Precision Parts and Prototypes
- Min. wall
- 0.8 mm
- Tolerance
- ±0.25% (min ±0.25 mm)
- Layer height
- 0.05–0.1 mm
- Build volume
- 1500 × 750 × 550 mm
metal
Direct Metal Laser Sintering (DMLS)
Volume Production of High Performance End-Use Parts
- Min. wall
- 1.0 mm
- Tolerance
- ±0.3% (min ±0.3 mm)
- Layer height
- 0.02–0.08 mm
- Build volume
- 400 × 300 × 400 mm
Design rules
Core 3D printing design rules
The same questions decide whether a part prints well on any process: wall thickness, tolerances, overhangs, minimum feature size, clearances and how material escapes from hollow sections. Start here, then use the guide for your process for exact values. For support planning, read our guide to supports and part stabilization.
Wall thickness
Most processes need walls of 0.8–1.0 mm; see each process in the table above. Unsupported walls that extend freely need more: 1.5 mm in SLS, or they can warp during printing.
Tolerances
Additive tolerances scale with part size, typically ±0.25–0.3% with a floor of ±0.25–0.5 mm depending on process. Call out critical fits on your drawing; tighter tolerances can be reviewed by our engineers or reached by post-machining.
Overhangs and supports
SLS and MJF need no supports because the surrounding powder holds the part. SLA, FDM and DMLS support overhangs and bridges, which affects surface finish and cost. PolyJet can print any overhang angle.
Fine features and minimum feature size
In SLS, engraved and embossed details need at least 0.5 mm width and depth, and freestanding pins at least 0.8 mm diameter. PolyJet resolves engraved details down to 0.2 mm.
Clearances for moving parts
Leave a gap between mating or moving parts so they do not fuse: at least 0.5 mm on all sides in SLA and 0.2 mm in PolyJet. Print-in-place hinges and chains need more room.
Hollow parts and escape holes
Hollowing saves material and weight, but unsintered powder must escape. Use one escape hole of at least 4 mm, or two of at least 2 mm for parts larger than 50 × 50 × 50 mm.
Threads and inserts
Printed threads work best at M6 or larger with profiles designed for plastics. For smaller or high-wear threads, use heat-set or threaded inserts, or tap the hole after printing.
Orientation
Orientation changes strength, surface finish and accuracy. SLS parts are close to uniform in every direction, while FDM parts are weakest between layers, so align loads with the layers.
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