3D Product Design for Additive Manufacturing 1 — Questions and Answers
Question 1: What is the generally recommended minimum wall thickness for structural FDM printed parts using a 0.4mm nozzle?
- 0.2mm
- 0.4mm
- 1.2mm (Correct answer)
- 5.0mm
Correct answer: 1.2mm
1.2mm equals approximately 3 nozzle widths at 0.4mm, providing adequate structural integrity for most FDM applications.
Question 2: What is the maximum overhang angle from vertical that typically does NOT require support structures in FDM printing?
- 15°
- 30°
- 45° (Correct answer)
- 60°
Correct answer: 45°
The 45° rule states that overhangs up to 45° from vertical can self-support because each layer only slightly overhangs the previous one.
Question 3: Which computational design technique removes unnecessary material from low-stress regions while maintaining required structural performance?
- Boolean subtraction
- Topology optimization (Correct answer)
- Shell modeling
- Parametric scaling
Correct answer: Topology optimization
Topology optimization uses algorithms to iteratively remove material from low-stress areas, producing lightweight, organically shaped parts that still meet load requirements.
Question 4: What is the primary reason to minimize support structures in a DfAM design?
- Supports increase print time, consume material, and require post-processing removal (Correct answer)
- Supports reduce nozzle temperature accuracy
- Supports cause layer delamination in the main part
- Supports limit the maximum build height
Correct answer: Supports increase print time, consume material, and require post-processing removal
Support structures add print time, waste filament, and must be manually removed in post-processing, often leaving surface blemishes at contact points.
Question 5: What is a 'living hinge' in the context of 3D printed product design?
- A hinge joint lubricated during printing
- A thin flexible section integrated into the part that functions as a hinge without hardware (Correct answer)
- A motorized hinge powered by a printed mechanism
- A hinge that requires assembly of two separate printed halves
Correct answer: A thin flexible section integrated into the part that functions as a hinge without hardware
A living hinge is a thin, flexible region printed integrally with the part, allowing repeated bending without separate fasteners or hardware.
Question 6: Which design strategy best exploits additive manufacturing's unique ability to create complex internal geometries?
- Simplifying all external profiles to flat planes
- Integrating internal cooling channels, hollow cavities, or lattice infill (Correct answer)
- Adding draft angles to every face
- Maximizing solid cross-sections throughout
Correct answer: Integrating internal cooling channels, hollow cavities, or lattice infill
Additive manufacturing uniquely enables internal channels, hollow structures, and conformal features that are impossible or prohibitively expensive with subtractive methods.
Question 7: A designer is creating a tall, narrow FDM part with a small footprint. Which printing aid should be considered during design to prevent warping?
- Reducing infill density to 5%
- Adding a brim or raft in the design file or slicer settings to improve bed adhesion (Correct answer)
- Increasing layer height to 0.5mm
- Printing the part on its side to increase footprint
Correct answer: Adding a brim or raft in the design file or slicer settings to improve bed adhesion
Brims and rafts increase bed contact area for parts with small footprints, preventing warping caused by thermal contraction forces pulling the part off the bed.
3D Product Design for Additive Manufacturing 1
What is the generally recommended minimum wall thickness for structural FDM printed parts using a 0.4mm nozzle?