FDM Design Guidelines
Learn how to design for succes when it comes to the FDM printing process.
The process
Fused Deposition Modeling (FDM) describes the technique of heating a thermoplastic to a semi-liquid state to deposite it in fine beads along the extrusion path. When support or buffering is needed, the printer deposits a removeable material that acts as scaffolding. Common plastics like ABS, Nylon, PC, PLA and ULTEM can be printed using this technique. An illustration of the FDM process is provided in the figure below.
Advantages
- Fully functional thermoplastic parts
- Low volume series production directly possible
- Durable parts with great stability
- High accuracy and moderate surface finish
Disadvantages
- Anisotropic material properties (weaker in build direction)
- Shrinkage and warping due to elevated temperatures
General guidelines
- Depending on the geometry and technique, shrinkage and warpage may occur
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Tolerances are generally always better in X-Y plane compared to Z-plane
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The minimum reliable hole size for most techniques is 1.5 mm
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Try to use washers surrounding holes which require bolted connections in order to decrease local
stresses -
Smallest possible text on parts is 6 pt, or 2.1 mm
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When text, numbers or drawings are needed on the part, it is preferred to have them sunk into the part with a minimum
depth of 1 mm
