Lesson 5: Safety Protocols and the Physical Fabrication Interface

Estimated time: 60-90 minutes

Learning Objectives

• Describe the Hierarchy of Controls and apply it to a classroom maker-space^{1 2}
• Perform pre-print environmental and equipment checks¹
• Validate the digital-to-physical pipeline and document post-print inspection results^{3 4}

Materials

• Classroom 3D printer, enclosure, and filtration (or documented lab SOP)
• Example parametric OpenSCAD project and slicer profile

Step-by-step Tasks

1. Conduct a safety briefing: review the Hierarchy of Controls and locate safety equipment¹.
2. Verify environmental controls and printer readiness: confirm filtration, bed adhesion, and spool metadata^{1 2}.
3. Run 3dm build and inspect the STL in a slicer; check layer-preview and non-manifold warnings^{3 4}.
4. If using remote submission (OctoPrint), confirm camera monitoring and logging before any unattended prints¹.
5. Obtain instructor sign-off and monitor the first layers in-person or via camera.
6. After printing, wait for the part to cool (< $30^\circ\text{C}$), measure critical dimensions, and record observations^{1 2}.

Checkpoints

• Completed environmental checklist and saved inspection notes in the project README^{3 1}.

Introduction to Material Selection

Before your part goes to print, it’s important to understand how material choice affects the printing process, the final product’s properties, and the safety considerations for your workspace.

Why Material Choice Matters

Most projects in this class use PLA - and for good reason. It’s the easiest, cheapest, and lowest-emission option. But as you advance, you’ll encounter projects that require different materials:

• A flexible phone case needs TPU (thermoplastic polyurethane)
• A functional bracket that will be outdoors might use PETG (polyethylene terephthalate)
• A decorative miniature works perfectly in PLA

Three Common Materials: Quick Reference

Each material has different print temperatures, strength properties, and difficulty levels. Here’s a quick comparison:

How Material Choice Affects Your Slicer Settings

When you switch materials, you must adjust:

• Nozzle Temperature: Too cold and plastic won’t extrude; too hot and it burns
• Bed Temperature: Helps adhesion; critical for PETG, optional for PLA
• Print Speed: TPU requires very slow speeds (20-30 mm/s) to prevent extrusion problems
• Cooling: PLA benefits from active cooling; TPU does not

Most slicers (like PrusaSlicer) have material profiles that automatically set these values. Always verify the temperatures match your filament’s specifications (check the spool label).

Environmental and Safety Considerations

Different materials produce different levels of emission:

• PLA: Lowest concern; generally safe in ventilated rooms
• PETG: Low emission; still requires good ventilation
• TPU: Moderate to higher emission; requires active ventilation or filtration

Always follow your classroom’s safety protocol and consult Appendix B: Material Properties & Selection for a comprehensive reference on all available materials, their specifications, and best practices.

Looking Ahead: Material and Design Decisions

Later in this curriculum, you’ll encounter projects that specifically require:

• Flexible materials (Lesson 8: Assembly and Durability)
• High-strength materials (Lesson 10: Quality Assurance and Measurement)
• Multiple-material assemblies (Lesson 11: Stakeholder-Centric Design)

By understanding material properties now, you’ll be prepared to make informed design decisions in those lessons.

Quiz - Lesson 3dMake.5 (10 questions)

1. What are the four levels of the Hierarchy of Controls¹?
2. Name two engineering controls useful for reducing emissions^{1 2}.
3. Why must you monitor the first layers of a new print profile¹?
4. Where should you record spool metadata and print observations^{3 1}?
5. What is the safe cooldown temperature suggested before part removal²?
6. True or False: Ventilation is only necessary for commercial printing facilities.
7. Describe the relationship between print temperature, material type, and emissions.
8. Explain what “spool metadata” includes and why tracking it is important for reproducibility.
9. How would you measure and record critical dimensions on a printed part?
10. What health and safety precautions should be documented in an SOP for supervised prints?

Extension Problems (10)

1. Draft a one-page SOP for start-to-finish supervised prints in your lab^{1 2}.
2. Create a checklist script that verifies spool metadata and build settings before 3dm build runs³.
3. Run a test print and log measured deviations; propose a parameter change to correct the error⁴.
4. Design an accessible post-print inspection checklist that non-visual users can follow^{1 2}.
5. Research filtration options and recommend one for your classroom, including maintenance intervals^{1 2}.
6. Develop a comprehensive classroom safety and operations manual: SOPs, checklists, emergency procedures, and accessibility considerations.
7. Create a print quality assurance system: define metrics, measurement methods, and acceptance criteria for finished prints.
8. Build a calibration and maintenance log: document all calibration activities, maintenance dates, and performance metrics over time.
9. Design a student training certification program: define knowledge and skill requirements, create assessments, and track competency.
10. Write an operations handbook that covers setup, troubleshooting, safety, maintenance, and accessibility for your 3D printing facility.

1. ANSI/AIHA Z590.3 - Hierarchy of Controls - https://www.aiha.org/ ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12 ↩13 ↩14

2. 10+ OpenSCAD Online Courses for 2026 | Explore Free Courses & Certifications, accessed February 18, 2026, https://www.classcentral.com/subject/openscad ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8

3. STL Validation and Geometry Checking - https://docs.prusa3d.com/en/guide/39012-validation-tools/ ↩ ↩2 ↩3 ↩4 ↩5

4. Post-Print Inspection Procedures - https://www.prusa3d.com/support/ ↩ ↩2 ↩3