# Full-Scale Unsplit M3 Prototype - Bambu Lab X1C

## Decision

This folder keeps the full Eastern Bluebird geometry, all six birdhouse parts
whole, and the M3 insert-and-bolt assembly system.

It does **not** contain a one-plate file. A credible one-plate arrangement is
not possible on the X1C while also keeping:

- 100% Eastern Bluebird geometry;
- the original 19.05 mm / 3/4 in. wall thickness;
- six separate, unsplit parts;
- independent build-plate support for every part; and
- normal X1C height and cutter safeguards.

The conservative minimum non-overlapping print envelopes total
122,941.7 mm2. The nominal 256 x 256 mm plate is 65,536 mm2. That is 1.876
plates of envelope area before any brim, support, clearance, or cutter
exclusion is added.

The supplied safe fallback is **four X1C plates**. No birdhouse part is split.

This is a material, printing, fit, and assembly validation prototype. It is
not evidence that printed thermoplastic is suitable for live-bird occupancy.

## Start Here

Use the four generic 3MF files:

1. `plate-01-back-front.3mf`
2. `plate-02-fixed-side-floor.3mf`
3. `plate-03-cleanout-side.3mf`
4. `plate-04-roof.3mf`

The files use millimetres and already contain the intended orientations and
placements. Import at 100%. Do not use auto-orient, auto-arrange, or scale to
fit.

Equivalent plate STLs and six individual part STLs are included if a slicer
does not preserve the generic 3MF components.

## X1C Fit

Bambu Lab specifies a 256 x 256 x 256 mm build volume for the X1C, but Bambu
Studio normally limits printable height to 250 mm and reserves a front-left
area for the cutter mechanism.

This package limits every part to 245 mm high and keeps the supplied geometry
inside the nominal plate:

| Part | Supplied print extent, mm | Orientation |
|---|---:|---|
| Front | 86.24 x 244.76 x 139.70 | Full 19.05 mm edge face on plate |
| Back | 139.70 x 215.88 x 245.00 | Leaned 49.77 degrees |
| Fixed side | 139.70 x 211.41 x 245.00 | Leaned 49.77 degrees |
| Cleanout side | 136.53 x 209.24 x 245.00 | Leaned 50.10 degrees |
| Floor | 19.05 x 139.70 x 101.60 | Full 19.05 mm edge face on plate |
| Roof | 234.95 x 140.82 x 245.00 | Leaned 62.31 degrees |

The red rectangle in `x1c-four-plate-layout-preview.png` shows the nominal
18 x 28 mm cutter-exclusion corner from the installed X1C machine profile.

## Slicer Setup

These are starting settings for a physical validation print, not a locked
production profile:

- X1C with the 0.4 mm nozzle;
- 0.20 or 0.24 mm layer height;
- six wall loops;
- six top and bottom shell layers;
- 20% to 30% gyroid or cubic infill;
- build-plate-only support for the leaned back, fixed side, cleanout side,
  and roof;
- an 8 mm brim on the leaned part only;
- no brim required for the front or floor unless the slicer preview shows a
  local adhesion problem.

For Plates 1 and 2, select only the leaned wall component when assigning the
brim. A global brim can consume the clearance reserved around the edge-up
front or floor.

Inspect every sliced layer before printing. The support must reach the lower
face of each leaned panel without filling the M3 pockets, bolt holes, vents,
entrance, drainage clips, or roof kerfs. Paint support blockers into those
features if the automatic support enters them.

Do not print a plate if Bambu Studio reports an exclusion-area, out-of-bounds,
height, or toolhead-collision warning. Do not disable the cutter or height
safeguards for this package.

## Material

PETG is a reasonable first material for indoor mechanical and assembly
validation. ASA may be useful for a later weathering comparison if it is
printed with appropriate ventilation and material handling. PLA is more
vulnerable to heat and creep.

No filament choice by itself makes this design suitable for occupancy. The
sellable kit remains the untreated-wood design until the project's physical
and species-review gates are completed.

## M3 Fit Test

Print `m3-insert-orientation-fit-coupon.stl` first.

The coupon tests 4.0, 4.2, and 4.4 mm pilot diameters in both side-entry and
top-entry orientations. The model currently uses:

- M3 insert thread;
- 6.0 mm nominal insert length;
- 5.0 mm maximum nominal insert outside diameter;
- 4.2 mm pilot pocket;
- 5.2 mm entry flare;
- 6.6 mm blind pocket depth; and
- 3.4 mm bolt clearance.

Use the coupon result for the actual insert lot and filament. If 4.2 mm is not
the best fit, update `INSERT_POCKET_DIAMETER_MM` in the base generator and
regenerate every part before committing to the full print.

## Hardware

The unsplit version removes all wall and roof seam hardware:

| Hardware | Quantity | Use |
|---|---:|---|
| M3 x 6 x 5 mm heat-set inserts | 17 | Body, floor, cleanout side, and roof |
| M3 x 25 mm stainless bolts | 17 | Matching assembly locations |
| M3 washers | 17 | Under exterior bolt heads |
| Thin nylon M3 washers | 2 optional | Low-friction cleanout pivots |

Bolt length is a starting value. Check the actual head, washer, wall, and
insert stack. A bolt must engage the insert without bottoming in the blind
pocket or projecting into the cavity.

## Assembly

1. Install and inspect all heat-set inserts before joining the body.
2. Put the fixed side between the front and back and install its four bolts.
3. Position the floor with its lower face 19.05 mm above the wall bottoms and
   install its four bolts.
4. Fit the cleanout side between the front and back.
5. Install the two lower M3 pivot bolts and optional nylon washers. Tighten
   only enough to remove unwanted play while preserving free movement.
6. Close the side and install the upper front latch bolt and washer.
7. Center the roof, seat it on the slope, and install its six bolts.
8. Open the cleanout side through its intended range and confirm that it does
   not contact the floor or roof.
9. Confirm that every drain and vent is open and that no bolt, insert, support
   remnant, burr, or sharp edge projects into the cavity.

## Validation Performed

`validation-report.json` records the generated checks:

- six valid, watertight, single-volume part STLs;
- four valid generic 3MF archives;
- correct plate component counts;
- all supplied plate coordinates inside 256 x 256 x 245 mm;
- valid six-solid STEP;
- 17 aligned M3 insert/bolt pairs;
- 3.175 mm total cleanout-side running clearance;
- closed assembly contact below the numerical collision threshold; and
- cleanout-side motion from 0 through 60 degrees without a modeled collision.

This is digital validation only. The package has not yet passed a real X1C
slice, physical print, heat-set insertion, assembly, wet/dry, thermal,
cleaning, UV, or occupancy review.

## Files

- `x1c-four-plate-layout-preview.png` - four supplied plate layouts
- `x1c-unsplit-assembly-preview.png` - closed and open assembly
- `one-plate-feasibility.csv` - minimum-envelope calculation
- `validation-report.json` - generated validation details
- `backyard-box-full-scale-m3-x1c-unsplit.step` - editable print-part CAD
- `01-...stl` through `06-...stl` - individual oriented parts

Regenerate from the parent `stl` folder:

```powershell
python .\generate_x1c_unsplit_vertical.py
```

## Sources

- Bambu Lab X1C product specifications:
  https://au.store.bambulab.com/products/x1-carbon-3d-printer
- Bambu Lab print-volume limitations:
  https://wiki.bambulab.com/en/knowledge-sharing/print-volume-limitations
- Prototype species and geometry sources:
  `../../PROTOTYPE_SPEC.md`
