3D Product Design for Additive Manufacturing 2

Question 1

When designing holes for press-fit inserts in an FDM part, what is the recommended approach?

Accepted Answer

Design holes 0.1–0.2mm undersized, then drill or ream to final size

Answer

Design holes exactly to nominal size

Answer

Design holes 1mm oversized to allow shrinkage compensation

Answer

Avoid printed holes entirely and always drill post-print

Question 2

What is the primary engineering benefit of incorporating lattice structures into a 3D printed product?

Accepted Answer

Significantly reducing mass while maintaining structural stiffness

Answer

Increasing part weight for added stability

Answer

Improving electrical conductivity of the part

Answer

Enabling easier post-processing and sanding

Question 3

When designing snap-fit joints for FDM printed parts, which material property pair is most critical?

Accepted Answer

Flexural modulus and elongation at break

Answer

Thermal conductivity and hardness

Answer

Electrical resistance and density

Answer

Tensile strength and thermal expansion

Question 4

What does 'functional integration' mean in Design for Additive Manufacturing?

Accepted Answer

Consolidating multiple traditionally separate components into a single printed part

Answer

Adding electronic components inside a 3D printed shell

Answer

Integrating software simulation into the design workflow

Answer

Using multiple filament materials in one print job

Question 5

Why must designers account for anisotropic mechanical properties when creating press-fit assemblies with FDM parts?

Accepted Answer

FDM parts are stronger in XY than along Z, so fit forces in the build direction may cause layer delamination

Answer

Anisotropy increases overall part density

Answer

FDM parts are stronger and stiffer along the Z (build) axis than the XY plane

Answer

Anisotropy only affects surface finish, not mechanical performance

Question 6

How does layer height selection affect the design of curved surfaces on an FDM part?

Accepted Answer

Thicker layers exaggerate the staircase effect on curved surfaces, which designers must consider for functional or aesthetic requirements

Answer

Layer height affects only print speed, not surface geometry

Answer

Smaller layer heights always reduce part strength

Answer

Layer height only matters for flat top and bottom surfaces

Question 7

What is the 'staircase effect' and how can part orientation in the slicer help mitigate it?

Accepted Answer

Visible layer stepping on angled or curved surfaces; mitigated by orienting critical curved features closer to vertical

Answer

Skipped layers from filament runout; prevented by using a runout sensor

Answer

Uneven first-layer adhesion; corrected by bed leveling

Answer

Warping on large flat surfaces; corrected by using an enclosure