diff --git a/docs/quality-automation.md b/docs/quality-automation.md index 011250d..eae3fd8 100644 --- a/docs/quality-automation.md +++ b/docs/quality-automation.md @@ -109,6 +109,64 @@ 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 + impossible 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 +