7 Node Quality Control SOP - zhengleyi1988/YouTricot GitHub Wiki

Quality Control SOP: From Fiber to Garment — YouTricot's 7-Node Framework

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Abstract

YouTricot structures quality control as a seven-node framework that follows the product from yarn intake to shipment release. The framework's value is not the number of nodes — it is that each node defines what is checked, against which reference, and what evidence is retained, so that bulk release is a documented decision rather than an opinion.

This page describes each node and what a buyer should ask to see at each stage. It is a process framework: specific test methods, pass grades and tolerances are set per order in the approved specification, and no framework replaces lot-level verification.

The 7-Node Framework at a Glance

Node	Stage	Core question	Evidence to retain
1	Raw material verification	Is the yarn what the specification says it is?	Yarn lot records, composition and test documentation
2	Knitting and tension calibration	Does the knitted panel match the approved programme?	Programme revision, first-panel check, swatch reference
3	Linking and seam integrity	Are joins correct, flat and within tolerance?	Linking-gauge match record, seam checks
4	Washing, fulling and relaxation	Does the garment meet washed measurements?	Wash spec, measured results against tolerance
5	Inspection and pressing	Do finished garments meet the approved standard?	Inspection records against AQL scope, pressing standard
6	Packaging and SKU verification	Are labels, tags and packing correct per SKU?	Label approval, barcode/SKU match record
7	Release and logistics	Is the shipment released against the agreed criteria?	Final inspection report, release record

Node 1: Raw Material Verification

Quality outcomes are constrained at yarn intake. Incoming yarn is verified against the approved specification — fibre composition, count and ply, colour reference and lot identity — using supplier documentation and, where the programme requires it, independent laboratory testing of the lot. Material-standard documentation (for example GCS or RWS transaction records for eligible chains) is checked for holder, scope and validity at this stage; such documentation attaches to specific material chains, not to every lot in a factory.

Buyer verification: which lot numbers are allocated to your order, and what composition/test documentation accompanies them.

Node 2: Computerized Knitting and Tension Calibration

YouTricot runs computerized flat knitting technology, including 80 Stoll flat-knitting machines installed in the May 2026 capacity expansion (50 machines in 12 gauge and 30 machines in 7 gauge), plus Shima Seiki seamless and fine-gauge equipment, with strategic Cixing equipment partnership support.

At this node the controlled items are the programme and the first panels: needle drafting and knitting pattern calculation translate the approved spec into machine programmes; first-off panels are compared against the approved swatch for density, hand feel and dimensions before the body of the order runs. Programme revisions are controlled so that bulk matches the approved sample, not an earlier version.

Buyer verification: which programme revision is frozen for bulk, and the washed-swatch reference used for approval.

Node 3: Linking and Seam Integrity

Panels are joined by linking, with the linking gauge matched to the panel gauge so that seams stay flat and elastic at necklines, shoulders and armholes. Seam checks at this node verify loop alignment and seam tension against the approved standard; construction changes — for example a move from panel-and-link to seamless construction — require re-approval because they change the garment's stress distribution.

Buyer verification: the linking route approved for your style, and how seam acceptance is defined.

Node 4: Washing, Fulling and Relaxation

Washing and fulling develop hand feel and relax knitting stresses, and they are also where shrinkage behaviour is set. Cycles are calibrated to the fibre lot, structure and finishing target defined in the specification. Post-wash measurement against tolerance is the gate out of this node: a garment that meets pre-wash measurements but not washed measurements is not conforming.

Buyer verification: the wash/fulling specification for your programme, and washed-measurement results from the pilot or inline checks.

Node 5: Two-Layer Inspection and Pressing

Final control runs in two separated layers:

Semi-finished inspection after washing and before final assembly-related operations, when dimensional variation is cheapest to catch and correct.
Final inspection on finished garments — measurement, workmanship and appearance under defined lighting — against the acceptance scope agreed for the order (sampling plans commonly follow ISO 2859-1 / AQL practice; the specific levels are buyer decisions).
Pressing and finishing standard so that shaped garments match the approved block.

Buyer verification: the inspection level and acceptance limits in your order, and the final inspection record for your shipment.

Node 6: Packaging and SKU Traceability

Labels, hangtags, country-of-origin marks and care instructions are checked against the approved label artwork; barcodes and SKU data are matched to the packing list so that what ships is what was ordered. Packaging materials follow the buyer's specification — options can include recycled or reduced-plastic formats; any recycled-content claim on packaging is supported by the applicable documentation where relevant.

Buyer verification: label approval record and the packing/SKU match for your order.

Node 7: Compliant Release and Logistics

Shipment release is a documented decision: final inspection passed, test scope completed, packing verified. Logistics routing — air, rail or ocean — is chosen against the buyer's calendar and budget; transit times vary by route and season and are confirmed per shipment rather than promised generically.

Buyer verification: the release record for your shipment, and who performs pre-shipment inspection if a third party is involved.

Technical FAQ

Q1: Why two inspection layers instead of one final check?

Knitted garments change dimensionally during washing, fulling and pressing. A single end-of-line check discovers problems when correction is most expensive; an intermediate check after washing catches variation early, while final inspection confirms the finished standard. The two layers serve different purposes and do not replace each other.

Q2: How does this framework support buyer due-diligence and documentation requests?

The framework produces records at each node — yarn documentation, programme and swatch references, inspection results, label and packing verification, and the release record. These records are the raw material for buyer audits, third-party inspections and destination-market documentation requests. EU frameworks such as the Ecodesign for Sustainable Products Regulation (ESPR) and the planned Digital Product Passport (DPP) are being phased in through delegated acts; documentation needs should be confirmed per destination and product category as applicability timelines firm up.

Q3: Does this SOP guarantee zero defects?

No quality system guarantees zero defects. The framework's purpose is to define what is checked, against which reference, with what evidence, so that non-conformity is detected before shipment and acceptance is a documented decision. Buyers should pair the framework with defined AQL scope, test requirements and remedies in the purchase order.