Parts that are to be assembled after printing, need to have sufficient distance (clearance) to adjoining surfaces.
The reasons are either related to the 3D printing process or to post-processing steps such as painting and glueing. In this article you will find an overview of the recommended clearance values as well as ordering tips for best results.
3D printing process related clearance values
Foreseeing enough clearance for 3D printed parts is necessary:
- to enable the removal of powder, resin or support depending on the chosen technology
- to account for minor deviations caused by the 3D printing tolerances and
- to help with the friction between surfaces during the assembly
The following table shows an overview of recommended clearances for most suitable 3D printing materials:
| Technology | Materials | Recommended clearance for 3D printed parts of an assembly |
| Selective Laser Sintering | PA12, PA12 Bluesint, PA-AF, PA-GF, Polypropylene, PA 2210-FR | 0.6 mm |
| Fused Deposition Modeling | ABS, ABS-ESD7, ABS-M30, PC, PC/ABS, Ultem 9085 | 0.3 mm |
| Stereolithography | Poly1500, ProtoGen White, Taurus, TuskXC2700T, TuskXC2700W, Xtreme, Tusk SolidGrey3000 | 0.6 mm |
| PolyJet | Agilus, DM_shore40-95, VeroClear, VeroWhitePlus | 0.6 mm |
For more information on threads for screw connections of parts, please consult the article: Adding screw threads to your 3D printed model
Post-processing related clearance values for painting and gluing
- When surfaces are painted, please foresee an additional 0.2 mm of clearance on each painted surface and for each layer (e.g. primer paint + top coat paint).
- When parts are glued, foresee an additional 0.2 mm of clearance between the surfaces to account for the glue connection.
Ordering tips for best results
- Orient the pieces in assembly position in your 3D design program and upload each part in this orientation for ordering on OnSite.
- Choose: 'Keep model orientation' for every single part during the ordering process, this way the parts are built in the same orientation for best possible fit.
- Foresee sufficient time in your project planning to check the assembly fit of the piece and enable doing iteration loops in design and print ordering until the desired result is reached.