Week 03 — 3D Scanning and Printing

1) Additive vs. Subtractive

• Subtractive: start with a solid block and carve away (mills, routers, laser cutters) until the form emerges.
• Additive: build up from nothing, stacking layers of material (3D printers, resin curing, powder-bed fusion).
• Constraint reminder: design something impossible to machine subtractively—think captive voids, continuous internal channels, or severe undercuts.

2) CAD — Organic ring → bangle (Rhino)

I wanted to remake an organic ring I wear but quickly discovered how thin jewelry fights FDM rules. Scaling the idea into a bangle saved the print and preserved the vibe.

1. Set Rhino document units to millimeters.
2. Sketch freeform curves inside a guide rectangle to capture the organic profile.
3. Use Pipe to give each curve printable thickness.
4. Connect forms with Loft or Sweep2 to get a continuous shell.
5. Add FilletEdge everywhere for wearable comfort.
6. Cap surfaces to confirm a watertight solid.
7. Run CheckMesh to verify it exports cleanly.
8. Measure ring and wrist with calipers/string and scale accordingly.
9. Export STL for slicing.

Thin ring walls kept collapsing during slicing tests; scaling up into a bangle gave the geometry enough body for 0.4 mm extrusion.

3) AI → CAD experiment (Meshy → Genie → Rhino)

1. Tested Meshy for AI-generated rings, but STL export sits behind a paywall.
2. Swapped to AI Genie (free STL export) with the prompt "organically inspired ring."
3. Imported the STL into Rhino—scale arrived at giant statue size.
4. Scaled down, then pivoted to making it a bangle to avoid thin sections.
5. Cut a wrist opening and tweaked edges in Rhino for comfort.

4) Slicing (PrusaSlicer — Expert mode)

Organic supports felt poetic for an organic bangle, and Expert mode unlocks them. Wood-filled filament needed a cooler nozzle to avoid scorching.

• Profile: Generic PLA, Expert mode.
• Layer height: 0.20 mm; Perimeters: 3; Infill: 15% Gyroid.
• Supports: Everywhere + Organic; Bed adhesion: Brim.
• Temps: PLA 200/60 °C; PLA+WOOD 190/60 °C.
• Observations: thin rings fused to supports; the bangle released cleanly.

5) Printing workflow (Prusa Core One, HF 0.4 mm)

1. Cleaned the build plate with isopropyl or water and soap.
2. Loaded filament and purged the filament to extract what was previously in the nozzle - do so until loaded filament colour visaible.
3. Started the print and nudged Z-offset as needed.
4. Let organic supports do the heavy lifting.
5. After cooling, flexed the plate for part removal.

Wood PLA clung to supports—likely humidity in the filament—while plain PLA detached effortlessly.

5.5) Dissolvable Supports Solution — Stratasys Machine

The organic supports failed because my object lines were quite thin. I then used the Stratasys machine with dissolvable supports and that was successful — printed in different scales and ended up with different ring sizes as well as a bracelet/bangle.

Settings & Process

• Machine: Stratasys with dissolvable supports
• Materials: Build material: ABS-M30 (Black) Support material: SR-30 (dissolvable, tan-white filament)
• Support type: Dissolvable
• Scales tested: [Add your scale details]

Results & Lessons

• Different ring sizes achieved through scaling
• Bracelet/bangle version worked well
• Dissolvable supports handled thin lines better
• This 3D printing process was successful and I was able to print different ring sizes and a bracelet/bangle. Recommended printing method for more fragile/thin objects.

Final Jewelry Results

Successfully created wearable jewelry pieces using the Stratasys printer with dissolvable supports, resulting in clean, delicate prints perfect for jewelry applications.

6) 3D Scanning (Creality CR-Scan Ferret Pro)

• Turntable mode, geometry-only capture, exported as STL for cleanup.
• Scissors scanned cleanly thanks to matte surfaces.
• Magnifying glass and stapler were too reflective—noise and holes everywhere.
• Short 1–2 minute scans plus manual cleanup beat long noisy sweeps.

7) Group Assignment — Design Rules (Prusa Core One)

• Overhangs: crisp up to ~30°; sagging appears near 20°.
• Bridges: reliable to 18 mm; 20 mm pushes it.
• Clearance: 0.2 mm separates with friction; ≥0.3 mm is smooth.
• Wall thickness: ≥0.6 mm; anything thinner delaminated.
• Infill: 15% Gyroid gave strength while staying fast.
• Dimensional accuracy: within ±0.05 mm near the base, drift grows with height.

8) Lessons Learned

• Design for ≥0.8–1.2 mm walls when printing jewelry with a 0.4 mm nozzle.
• Fillets and chamfers matter for wearables and reduce stress risers.
• Organic supports are lovely but demand patient post-processing.
• Wood-filled filament needs dry storage and gentle temps.
• Scanning reflective objects benefits from matte spray or alternative targets.

9) Image TODOs

Drop your actual media files into assets/img/ and replace the placeholders above.

• Rhino ring attempt
• Rhino bangle final
• PrusaSlicer preview with organic supports
• Wood PLA print result
• White PLA print result
• Scanner capture (scissors)
• Cleaned mesh STL

Sources

• Prusa Core One documentation and organic support overview.
• Rhino command reference (Pipe, Sweep2, FilletEdge).
• AI Genie — STL export.
• Creality CR-Scan Ferret Pro user manual.
• HTMAA recitations and group testing logs.
• ChatGPT (GPT-5) — brainstorming and documentation support.