# R3.1 light assembly and prototype checks

## Parts and placement

| Part | Quantity | Material/process intent |
|---|---:|---|
| R3.1 front shell | 1 | Existing chalk rigid-shell process; supplier to review the revised internal sleeve/cradle for the prototype process |
| R3.1 coaxial-flange lens | 1 | Clear optical polymer; lightly diffusing visible face, clear guiding surfaces; confirm grade and finishing process with supplier |
| Retained right-angle guide | 1 | Clear optical polymer with finished optical surfaces; same shape, moved down 3 mm |
| Optical coupling film | 1 | Optically clear adhesive, modeled thickness 0.05 mm; same shape and new Y=2 axis |
| LED | 1 | Existing purchased LED reference, rigidly relocated without altering its body or terminals |
| Keeper | 1 | Existing rigid prototype material and geometry, moved down 3 mm |
| Saddle liners | 2 | Existing compliant nonconductive material, moved with keeper/LED |
| Keeper screws | 2 | Existing M2 × 5 mm references, moved down 3 mm |

`C28_R3_1_PLACED_...` STEP files use the new assembly coordinates. The retained `C27_R2_...` names inside the assembly describe unchanged component geometry, not old placement instructions. In particular, the suffixes on the two original screw names no longer describe their current Y coordinates; use the R3.1 assembly and the table in the review.

## Assembly sequence

1. Use the new shell and new centered-flange lens as a matched pair. Clean the lens seat and guiding surfaces. Insert the lens from inside, seating its flange behind the unchanged circular opening. Verify seating without cracking, wedging or visible looseness; nominal clearance is not a supplier tolerance approval.
2. Place the 0.05 mm optical bond allowance between the lens rear face and guide output. Select an actually transparent, compatible adhesive; avoid bubbles, squeeze-out into guiding surfaces and pigment contamination.
3. Install the original guide, LED, liners and removable keeper at the new positions. The horizontal LED-to-guide relationship is unchanged. Do not trim the LED or force the guide to correct a misfit.
4. Use the two existing screw types at X=-7/Y=-3.4 and X=-7/Y=7.4 mm. Confirm pilot engagement and keeper seating on the physical sample. Retain the existing assembly torque qualification; no new torque is specified here.
5. Re-route the LED hookup slack to the new terminal position, 3 mm lower. No harness length or solder-joint strain qualification is implied by the solid clearance check. Ensure the keeper and cover cannot pinch a lead.
6. Check the installed indicator before closing the case, then again with the case closed. Use the intended LED colors and actual drive current. Inspect face-on and at the intended viewing angles, in normal room light and the intended bright-light use condition. Compare center/edge illumination and check for a dark crescent, RGB color separation or light leaking into the shell.
7. If output is inadequate, tune optical material, surface finish and the retained bend using a powered sample or optical analysis. Do not reduce shell support or LED clearances by eye.

No new brightness target is invented here. Agree the acceptance level using the intended operating environment and compare an assembled sample before a casting batch. The earlier switch measurements, U6 height verification and RF/antenna checks remain separate prototype requirements.