Week 05 · 3D Scanning and Printing

What I did in Week 05

This week's group assignment focused on testing and characterizing the design rules of our in-house 3D printer using a standard all-in-one benchmark. The process included two full print cycles, error diagnosis, and parameter adjustment.

Printer characterization: tested support, scale, overhang, hole, diameter, and bridging performance.
Failure analysis: identified overhang and print clarity issues and traced them to speed and nozzle settings.
Parameter adjustment: reduced outer wall, inner wall, and top surface speeds; switched to a finer nozzle.
Re-print: resolved a filament moisture error mid-print and completed a second 7-hour cycle.

Assignment for the week:

Group: test the design rules for your 3D printer(s).

The 3D Printer

We used the Bambu Lab A1 Mini for this assignment — a compact, high-speed FDM printer with multi-material capability and a fully enclosed toolhead cooling system.

[ Image: 3D Printer — image1.jpeg ]

Technical Specifications · A1 Mini

Full specs available at the official Bambu Lab tech specs page.

Body

Print Size	180 × 180 × 180 mm³
Frame	Steel + Aluminum profile

Tool Head

Hotend	All-metal
Extruder Gear	Hardened steel
Nozzle	Stainless steel
Max Nozzle Temperature	300 ℃
Nozzle Diameter (default)	0.4 mm
Optional Nozzle Diameters	0.2 mm · 0.6 mm · 0.8 mm
Tool Head Cutter	Built-in
Filament Diameter	1.75 mm

Heated Bed

Supported Print Surfaces	Smooth PEI · Textured PEI · Textured + Smooth PEI
Max Bed Temperature	80 ℃

Speed

Max Travel Speed	500 mm/s
Max Acceleration	10,000 mm/s²
Max Flow Rate	28 mm³/s @ ABS (280 ℃, 150×150 mm single-layer outer wall)

Supported Filaments

Recommended	PLA, PETG, TPU, PVA
Not Recommended	ABS, ASA, PC, PA, PET, Carbon/Glass Fiber Reinforced

Sensors & Connectivity

Camera	Low-frame-rate, up to 1920×1080, time-lapse support
Filament Runout	Supported
Power Loss Recovery	Supported
Filament Entanglement	Supported
Display	2.4-inch 320×240 touchscreen
Connectivity	Wi-Fi · Bambu-Bus · Micro SD
Motion Controller	Dual-core Cortex-M4

Software

Slicer	Bambu Studio; also supports SuperSlicer, PrusaSlicer, Cura
OS	macOS, Windows

Physical & Electrical

Product Size	347 × 315 × 365 mm³
Net Weight	5.5 kg
Input Voltage	100–240 VAC, 50/60 Hz
Maximum Power	150 W

Printing and Testing

We used the All In One 3D Printer test from Thingiverse. It covers support, scale, overhang, hole, diameter, and bridging tests. The file was printed at 100% infill without supports.

The STL was downloaded and uploaded directly to Bambu Studio for slicing.

Print parameters setup

[ Image: Print Parameters Setup — image2.jpeg ]

Sliced plate view (0.4 mm nozzle, default settings)

[ Image: Sliced Plate View — image3.jpeg ]

Estimated print time: 2 hours.

Results — issues detected

After printing, two problems were identified:

1. Overhang failure

[ Image: Overhang Failure — image4.jpeg ]

2. Print font clarity issue

[ Image: Print Font Clarity Issue — image5.jpeg ]

All other tested features were within acceptable quality.

Failure Analysis and Adjustments

The two problems were traced to speed and nozzle configuration. Here is the analysis and recommended corrections.

1 · Overhang fracture

Print speed too high: filaments do not have enough time to cool and cure before the next layer. Reduce speed, especially at high overhang angles.
Insufficient cooling: increasing fan power helps filaments solidify quickly, preventing sagging and breakage.
Temperature too high: excess material fluidity increases the risk of drooping. Reducing print temperature can help.

2 · Print font clarity

Nozzle diameter and layer height: finer nozzles and lower layer heights improve small-detail resolution.
Extrusion calibration: over- or under-extrusion blurs fine text; verify calibration before printing.
Print speed: slower speeds provide more stable material deposition, especially for small features.

Recommended speed corrections

Parameter	Original	Recommended
Outer Wall Speed	200 mm/s	100 mm/s
Inner Wall Speed	300 mm/s	150 mm/s
Overhang Speed	30 mm/s	30 mm/s (keep)
Top Surface Speed	200 mm/s	100 mm/s

Summary: The main root cause was high speed settings combined with the default 0.4 mm nozzle. Halving the outer wall and top surface speeds, and switching to a finer nozzle, should resolve both issues.

Re-Printing

New settings were applied and the print was restarted. Estimated time with the adjusted parameters: over 7 hours.

[ Image: New Settings — image6.jpeg ]

Nozzle replacement

The nozzle was replaced following straightforward steps.

[ Image: Nozzle Removal Steps — image7.jpeg ]

Note: When removing the nozzle, this secondary part must also be replaced.

[ Image: Part to Replace — image8.jpeg ]

Error during re-printing

Error: The print stopped mid-job due to incorrect PLA material input.

[ Image: Printing Error — image9.jpeg ]

After removing the nozzle and feed port, it was found that moisture had weakened the filament mid-spool, causing it to snap internally.

[ Image: Wet/Broken Filament — image10.jpeg ]

The broken section was cut away and the print continued without further issues.

Final Result

After a second complete 7-hour cycle, the final benchmark print was obtained.

[ Image: Final Print Result — image11.jpeg ]

The bridging section still showed minor imperfections, but the overall result was significantly improved across all other test categories.

[ Image: Overview of Final Print — image12.jpeg ]

Key takeaway: Reducing outer wall and top surface speeds to 100 mm/s and replacing the nozzle had the greatest impact on print quality. Moisture-damaged filament is a critical variable that must be controlled before any long print.

Next step

With printer design rules now characterized and documented, the next weeks will apply 3D printing to custom parts and final project components using these validated settings as a baseline.