cnx_vinyl/docs/quality-automation.md

# Quality Automation

The target is to automate as much as possible. For quality control this
means instruments and inspection stations that measure, decide, and log into
the [traceability system](traceability.md) without manual transcription.
Research findings from vendor sites and trade sources, July 2026; the
recommended architectures are engineering positions to be validated with
vendors, not purchased designs.

## Stamper, father, and mother metrology

What must be measured on the electroformed nickel parts (~0.2 to 0.3 mm
thick): groove geometry (grooves are 40 to 80 microns wide, ~28 microns
deep, 200 to 350 grooves per inch, inverted to ridges on a stamper),
thickness uniformity (total thickness variation of 10 to 20 microns is the
achievable target, by analogy with CD stamper practice), surface roughness
on the groove walls, and micro-defects.

A Keyence-class instrument stack covers this, in tiers:

- **Keyence VK-X 3D laser confocal microscope**: 20 nm vertical and ~120 nm
  lateral resolution, non-contact. The reference-grade instrument for groove
  cross-sections, wall roughness, and fine defect analysis. Scanning the
  full spiral (hundreds of meters of groove or more) is not feasible; the
  correct strategy is **sampled radial zones** (lead-in, outer, mid, inner
  radius). The optical disc industry verified its nickel stampers with the
  same instrument class, so the technique transfers directly.
- **Keyence VR-6000 wide-area profiler**: 0.1 micron height resolution,
  ~1 second per field, with an HDR mode built for glossy surfaces (bright
  nickel is near-mirror, the classic hard case for optics; manageable, but
  plan tuning time). Fast wide-area form, flatness, and gross defect
  mapping.
- **XRF thickness gauge** (Fischer/Bowman class): non-destructive nickel
  deposit thickness per serial, replacing the industry's manual 10-point
  micrometer practice. Thickness must be read on the outer land/shoulder
  zones, not across the groove field.
- **Stylus profilometer** kept as the traceable calibration reference.
- **Inline machine vision** for fast 100% cosmetic screening of every part.

Integration is real but not turnkey: the Keyence instruments export CSV and
raw 3D data and support scripting/REST layers, and the inline sensors speak
Ethernet/IP, but there is no off-the-shelf MES connector. Budget a light
middleware service that stamps each measurement with the part serial and
batch ID and writes to the genealogy database.

Industry context: even a respected stamper house checks thickness with a
hand micrometer at 10 points on sacrificial blanks, with nothing logged.
Automated non-contact metrology with per-serial logging is ahead of current
industry practice, which is exactly the point: it makes every father, mother,
and stamper a data-backed accept/reject decision before the next plating
generation or press mounting.

## Pressed record QC: three layers

Full automated audio checking of every record is physically impossible: a
12" record plays for ~40 minutes both sides while a press makes a new record
every ~25 seconds, so one press outruns roughly 80 to 95 full-time listening
stations. No commercial playback-QC robot exists anywhere. The credible
maximum-automation architecture is layered:

### Layer 1: 100% optical inspection, inline

Machine vision can inspect every record at line speed. Detectable with
darkfield lighting and line-scan cameras: non-fill (dull patches where PVC
did not fill the stamper), stitching and flow lines, warp (via structured
light or profilometry), off-center spindle holes (concentricity of hole vs
groove spiral), surface debris, and label errors (wrong label, off-center,
print defects). Non-fill and stitching correlate with audible defects, so
optical inspection is a strong proxy for audio quality without playing the
record.

No vinyl-specific vision product exists; this is a custom integration of
general machine vision (Keyence or Cognex class) at the press unloader. CNX
would be an early adopter, and it should be budgeted as an integration
project.

### Layer 2: press telemetry, every cycle

The proven, deployed piece. Viryl's ADAPT platform demonstrates the model:
per-cycle nozzle pressure, mold temperatures, cycle time, cake weight,
yields, and drift alerts streamed from the press. The Pheenix AD12 runs a
Beckhoff PLC exposing similar data over standard industrial protocols, and
supports remote monitoring. Machine data access is already flagged as a
procurement requirement in the traceability spec.

### Layer 3: automated audio comparison, sampled

A needle-drop capture station with automated analysis, run on samples:
every test pressing / first-off per stamper, plus pulled samples scaled by
stamper age (stampers last roughly 1,000 to 2,000 records; sampling should
densify near end of life; industry rule of thumb is a spot-play around every
50th record).

The analysis pipeline is buildable from proven parts but is a first-of-kind
system as a whole:

1. Capture the needle-drop (a conventional tonearm; laser pickups exist but
   are dust-sensitive and impractical as line instruments)
2. Spectral-envelope comparison against the source master (the approach
   proven by Stamper Discs' Fonograph tool, which avoids the hard
   time-alignment problem by comparing whole-program FFT fingerprints)
3. Click/pop detection and counting (mature algorithms of the iZotope RX
   class, scriptable)
4. Noise floor from lead-in/run-out silence, channel balance from program
   RMS
5. Numeric scores and pass/fail to the traceability database

What only this layer can catch: wrong master cut into good-looking grooves,
EQ/mastering errors, and speed/pitch problems. Optical and audio layers are
complements, not substitutes.

## The traceability payoff

The natural record identity is **stamper ID + press ID + cycle timestamp +
side**. Against that key: press telemetry on every cycle, an optical result
on every record, an audio score on every sampled record, and the stamper's
own metrology history from before it was mounted. Audio scores trending down
against a stamper's play count become an automatic retirement signal, and a
customer complaint about one record resolves to a specific stamper, press,
shift, and compound lot.

## Honest limits

- No vendor sells a turnkey version of layers 1 or 3, or the metrology
  middleware; all three are integration/development projects
- 100% audio QC of every record is not achievable at press speed and should
  never be promised to customers; 100% optical plus sampled audio is the
  accurate claim
- Human listening stays in the loop for test-pressing approval; the
  automation makes sampling systematic and logged, it does not replace ears