In general

Every technology in AM has got specifice capabilities and limitations.

Design has to  accommodate the layer-by-layer nature of 3D printing to avoid overhangs, warping, and other issues.

Unlike subtractive manufacturing, AM doesn’t  start with a solid block or billet of material and the of using various tools (such as drills, mills, lathes, or routers) to cut away excess material until the final shape and dimensions of the part are achieved.

Structural Considerations

Wall Thickness:

• Maintain consistent wall thickness to ensure strength and avoid weak points.
• Minimum wall thickness varies by material and technology; typically, 0.8mm for plastics and 1.0mm for metals.

Overhangs and Bridges:

• Design overhangs with an angle of 45 degrees or less from the vertical axis to minimize the need for support structures.
• Use bridging techniques for horizontal gaps but keep them short (less than 10mm).

Supports and Rafts:

• Minimize the need for supports by designing with self-supporting angles and shapes.
• When supports are necessary, ensure they are easily accessible for removal.

Detail and Tolerances

Detail Size:

Ensure fine details are above the minimum feature size of the printer (typically 0.5mm for FDM, 0.2mm for SLA, and 0.3mm for SLS).

Tolerances:

Allow for tolerance gaps in assembly parts (typically 0.2mm to 0.5mm depending on the printer’s precision).

Part Orientation and Build Direction

Optimize Orientation:

• Orient the part to minimize the number of supports and maximize strength along the desired axis.
• Consider the anisotropic nature of 3D printed parts and orient the part to maximize strength in critical areas.

Layer Height:

• Choose an appropriate layer height based on the desired balance between surface finish and print time. Thinner layers yield better surface finish but increase print time.

Surface Finish and Post-Processing

Surface Finish:

Design parts with post-processing in mind if a smooth finish is required (e.g., sanding, polishing, coating).

Text and Labels:

Emboss or engrave text and labels with a depth or height of at least 0.5mm for readability.

Complex geometries and lightweight Structures

Complex Geometries:

Take advantage of AM’s ability to produce complex geometries that are impossible or difficult with traditional manufacturing methods.

Lightweight Structures:

Utilize lattice structures and internal geometries to reduce weight while maintaining strength.

Material specific considerations

Material properties:

Design according to the material’s properties such as flexibility, strength, and thermal resistance.

Shrinkage and Warping:

Account for potential shrinkage and warping, especially in large parts or those made with high-temperature materials.

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