Design for Additive Manufacturing Flashcards

What are the best practices for designing readable text or logos on an FDM printed part?

Answer: Emboss or engrave text at least 0.5–1mm deep or high using simple, bold sans-serif fonts

Text thinner than 0.5–1mm often fails to print or lacks legibility; bold sans-serif fonts at adequate relief ensure the features resolve correctly and remain readable.

What is 'self-supporting geometry' as a DfAM design principle?

Answer: Designing geometry that stays within printable overhang limits so no support structures are needed during printing

Self-supporting geometry uses design rules such as keeping overhangs within 45°, using arches, teardrops for holes, and chamfers to eliminate support material entirely.

Why are chamfers on bottom edges of FDM parts often preferred over fillets in DfAM?

Answer: Chamfers reduce the elephant's foot effect and do not require support material unlike bottom fillets

Bottom fillets create an unsupported curved surface requiring support material, whereas chamfers replace that curve with a flat angled face that is self-supporting and also reduces first-layer spread (elephant's foot).

Why is mesh integrity (no non-manifold geometry or gaps) critical when preparing an STL or 3MF file for functional parts?

Answer: Slicers require a watertight mesh to compute valid toolpaths; gaps cause print failures or missing geometry

Slicing software needs a fully closed, watertight mesh to correctly determine inside versus outside and generate accurate toolpaths; any gaps or non-manifold edges can cause missing walls or failed prints.

What clearance is typically recommended between mating FDM printed parts in an assembly to ensure proper fit?

Answer: 0.2–0.5mm per side to account for FDM dimensional tolerances

FDM tolerances are typically ±0.2–0.5mm, so designing 0.2–0.5mm clearance per mating surface ensures parts fit together after printing without requiring significant post-processing.

What is the main engineering advantage of designing 'print-in-place' mechanisms for 3D printed assemblies?

Answer: Moving assemblies such as hinges and joints are printed fully functional in a single job, eliminating assembly steps

Print-in-place designs use precisely controlled clearances between moving parts so that a complete, functional mechanism comes off the printer ready to use without any additional assembly.

What is the fundamental shift in design philosophy between traditional 'Design for Manufacturability' (DFM) and 'Design for Additive Manufacturing' (DfAM)?

Answer: Traditional DFM minimizes geometric complexity to ease machining, while DfAM embraces complexity wherever it adds function or reduces part count

Traditional DFM avoids complex features because machining them is costly; DfAM leverages additive manufacturing's ability to create complex internal structures, organic shapes, and consolidated assemblies at no added cost per feature.