imrishabh18/nema-23-stepper-controller

fabrication-review.md

# Fabrication review — revision G

**Copper connectivity: PASS. Manufacturing release: HOLD pending fabricator DFM and remaining assembly review.**

Reviewed local circuit JSON SHA-256: `0142c069518b87fe781a9258750d2de92892028e260371981003124bf510529b`. All 19 release checks passed at 2026-10-14T12:54:27.267Z The curved revision G retains the CH224A/DRV8452 circuit and all 457 electrical source connections. The PCB is now 56 × 56 mm with ST-M10-reference recesses and a 50 × 32 mm rear hole pattern. Exact motor-cover fit and screw engagement are not established by that adapter drawing. No current manufacturing export has been generated for revision G; existing revision F exports must not be used for this outline.

## Copper and footprint results

The independent vector audit inspects pads, traces, vias and pours, subtracts plated and non-plated drills, and joins layers through plated barrels. It compares the resulting physical graph with the source netlist. There are 460 copper-bearing pad ports, 118 electrical copper networks, 10 connected pours, and no unintended shorts, broken required connections, floating copper fragments, unresolved net identities or pads erased by drilling. Ground is one connected physical network.

There are 120 bare-copper components: two terminal pairs connect internally through populated [Alps SKRPACE010 switches](https://tech.alpsalpine.com/e/products/detail/SKRPACE010/). Those exceptions are explicit; switched sides remain separate. Intentional unused/NC pads are not floating pours. Six fault-injection cases exercise shorts, missing barrels, floating pours and drill failures.

All 11 CH224A and 25 TPS26630RGET pads match their exact supplier imports after physical placement rotation, including numbering, dimensions and shape. Supplier pin-1 baselines match. U_PD exports at 90°, U_EFUSE at 270° and the bulk capacitor at 0°. Bulk nominal manufacturer pitch is 5 mm with 1 mm board holes; supplier CAD uses rounded 5.08 mm. The audit records this distinction. See `checks/selected-part-footprints.json` and `engineering/easyeda/selected-parts-manifest.json`.

## Findings before ordering

1. **The intended 2 oz outer copper conflicts with existing fine traces under the screened JLCPCB profile.** Existing fine traces remain below 0.15 mm; minimum width is 0.10 mm. [JLCPCB's published multilayer 2 oz limits](https://jlcpcb.com/capabilities/pcb-capabilities) are 0.15 mm track width/spacing. Reroute for the selected process or obtain manufacturer approval. Changing to 1 oz requires reassessing motor-path current and temperature. Spacing, hole-to-copper and soldermask also require manufacturer DFM.
2. Requested 0.30 mm holes / 0.45 mm pads have a nominal 0.075 mm radial ring; confirm the chosen process. Select suitable treatment for the 18 exposed-pad thermal vias to control solder wicking.
3. The export still reports three legacy assembly warnings: J_USB pin-1/180° rotation unverified, D_PWR supplier pin-1/0° rotation unverified, and U_PD_BUFFER supplier/local pin-1 baselines incompatible at 0°. Review these before ordering PCBA. The changed PD/eFuse parts and bulk capacitor do not produce these warnings.
4. Confirm the ST-M10-reference 50 × 32 mm rear pattern against the actual motor, screw engagement, cable exit and heatsink attachment/base clearance. The generic NEMA23 model does not establish actual mounting compatibility. Firmware, temperature/current calibration and motor-body thermal behavior need prototype validation.

Passing project DRC does not establish compliance with the selected manufacturer's production process. The preliminary screen is in `checks/fabrication-screen.json`.

## Archived revision F manufacturing export

`dist/index/cloud-drc-fix-gerbers.zip` and the delivered `fabrication/gerbers.zip` contain the same 17 exported files: all four copper layers, outline, masks, paste, silkscreens, fabrication drawing, plated/non-plated drills, BOM and pick-and-place. Those archived revision F drill counts are 335 plated hits/slots, including 321 vias and 14 plated holes. Revision G has 314 vias and needs a new export after mechanical and manufacturing qualification. Archive and member hashes plus selected-part BOM/placement assertions are in `checks/ch224a-fabrication-export-manifest.json`.

Do not upload those archives as revision G. Generate and review one matching Gerber/BOM/placement set from the qualified current board. Selecting CH224A against old CH224Q Gerbers would also create a package mismatch.

## Historical sourcing evidence (2026-10-07)

CH224A / [C42459160](https://jlcpcb.com/partdetail/WCH_Jiangsu_Qin_Heng-CH224A/C42459160) replaces unavailable CH224Q; JLCPCB showed 17,855 in stock when checked. Its interface and package are supported by the [WCH CH224 datasheet](https://www.wch-ic.com/downloads/CH224DS1_PDF.html). The stocked eFuse is TPS26630RGET / C2864391, the same TI device/package in a different reel quantity, now imported against that exact supplier selection. Bulk capacitor Panasonic EEU-FR1J221L / C178712 is 220 µF / 63 V, 10 × 25 mm with nominal 5 mm lead pitch. It is listed for wave soldering; confirm assembly availability for the chosen order. Stock is time-sensitive and has not been reserved. Primary evidence and dated stock checks are in `engineering/bom-sourcing-2026-10-07.json`.