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.

## Raw PVC compound QC, per lot

Every incoming compound lot passes a gate before release to production, and
the lot ID follows every record pressed from it:

- **Paper first**: supplier certificate of analysis per lot, checked against
  the agreed specification; a retained sample of every lot is archived
- **Moisture**: verify the compound is within the moisture spec before it
  reaches the extruder (moisture causes surface defects and noise); a
  benchtop moisture analyzer is a cheap, automatable check
- **Melt behavior and thermal stability**: a melt-flow or rheology check per
  lot catches drift in processing behavior, and a heat-stability check
  matters specifically for PVC (degradation releases hydrochloric acid and
  shows as discoloration and noise); these are standard plastics-lab
  instruments with data export
- **Color and appearance**: spectrophotometer reading against the reference
  for black and colored compounds; granulate size and dust content by
  sampling
- **Release by test pressing**: a new lot, and especially a new supplier, is
  released only after test pressings from that lot pass optical and audio
  QC; this is the backbone of the local-supplier qualification protocol,
  since qualifying Thai/regional compound against European references is an
  explicit goal
- **Regrind stream QC**: the in-house 20% recycled stream is its own
  material source and needs its own gate: no labels, paper, or foreign
  material entering the grinder, contamination checks on regrind batches,
  and verification of the virgin/regrind ratio at the extruder; regrind
  batch IDs are logged like any other lot

## Packaging QC

Packaging comes from local carton partners, so QC splits into an incoming
gate and an assembly gate:

- **Incoming cartons and sleeves, per delivery**: dimensional checks
  (records must fit without force; spine width per title), board grammage
  and thickness, print quality against the customer-approved proof
  (spectrophotometer Delta E for color-critical jobs), lamination/finish,
  and seam strength; results logged per packaging lot and fed back to the
  partner
- **Inner sleeves**: verified for scuff risk (surface finish matters more
  than looks; a bad inner sleeve scratches every record put in it)
- **Print inspection is automatable**: camera-based print inspection is a
  mature field, and the same vision investment as the record label check
  can cover jacket print defects
- **Assembly verification, automated**: the highest-value check is that the
  right record goes into the right jacket; scanning the runout matrix code
  against the jacket barcode at the packing station makes mismatches
  systematically caught rather than unlikely, and confirms inserts and
  extras per the order's bill of materials
- **Barcode verification** on every finished unit (a misprinted barcode is
  a rejected delivery at the distributor)
- **Shrink wrap and final visual** on a sampling basis

Both gates write to the same traceability chain: compound lot and regrind
batch attach to every press cycle, packaging lot and assembly checks attach
to every order.

## 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