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DFAM: Design Rules for 3D Printing

42 rules for geometry, assembly, optimisation and orientation, with numbers per technology

DFAM is designing for the process itself: the part is drawn so it comes out of the machine rather than being repaired after it. Every rule here carries a number for FDM, SLA, SLS and DMLS, the reason behind the number, and what breaks if you go below it.

If you need the meaning of a word rather than a design number, it lives in the glossary.

Rules42
Themesgeometry, assembly, optimisation, orientation
TechnologiesFDM, SLA, SLS, DMLS
Accessfree, no registration
Minimum Wall ThicknessOverhang / Self-Supporting AngleMaximum Bridge LengthMinimum Hole DiameterMinimum Printable ThreadSLA Drainage Holes for Hollow PartsSLS Powder-Escape PocketsFillets vs Sharp Internal CornersEmbossed and Engraved Text / Small Feature SizeFirst-Layer Chamfer / Elephant Foot AvoidanceSharp Internal Corner Stress Failure ModesTeardrop Profile for Horizontal HolesClearance for moving / mating partsDimensional toleranceSnap-fit designLiving hingePress-fit jointHeat-set threaded insertPrinted threads / threaded jointsInterference vs clearance fit selectionIn-situ printed assembly (print-in-place)Joint orientation for load directionBonded joint (adhesive assembly)Lattice & Gyroid StructuresTopology OptimizationPart ConsolidationGenerative DesignInfill Strategy (DfAM Perspective)Lightweighting / Mass ReductionDesign for Minimal MaterialConformal Cooling ChannelsSupport MinimizationBuild Orientation OptimizationAnisotropy / Layer adhesion (XY vs Z)Support strategy (SLS vs DMLS)Residual stress and stress relief (DMLS)Build orientation decisionSelf-supporting design (minimising supports)Surface finish vs orientationWarping and first-layer adhesionTilt orientation strategy (SLA/MSLA)Nesting and packing (SLS build volume)