Circular Knitting Machine Order Changeover: Release the First Roll After a Yarn Lot Switch

Compare the supplier designation, fibre blend, yarn count and count system, spinning route, twist description, colour reference, package format and treatment information available for both lots. Separate a genuine equivalent-lot replacement from a material substitution that requires a wider approval. Record missing supplier data as unknown, rather than filling the gap with the last order's certificate.

Allocate packages to named feed positions and keep the outgoing map. Partly consumed cones, spare packages and returned stock need explicit lot labels because they can reintroduce the old material after startup. Retain representative old and new yarn references under the mill's storage procedure. If the incoming shipment contains more than one lot, define which combination the trial represents before loading begins.

Use the machine's approved changeover procedure to record when each feed receives the new lot. A simultaneous planned replacement and a gradual package-by-package change produce different traceability problems. Keep those routes distinct in the roll record. Mark the last known old-lot interval, the transition interval and the first interval for which all participating feeds are verified as new lot.

Give transition material its own disposition, even if it looks usable. Do not merge it into the accepted roll merely because the machine ran without stops. Log threading corrections, cleaning, speed changes and stop events alongside the lot event so later inspectors can distinguish a material boundary from an operating disturbance. Any protected adjustment still belongs to trained personnel following the supplied machine instructions.

Take identified bands from the retained accepted material and the fully replaced trial interval. Compare both faces over a representative width or circumference using the agreed illumination, relaxation state and inspection rules. Track yarn-related bars separately from needle lines, holes or restart marks; a single defect label can otherwise conceal several unrelated changes.

Where dyeing or another finish determines saleability, process the paired samples through the same documented comparison route. Check the order's relevant shade, weight, width and dimensional requirements, recording which results remain pending. If the new lot differs, investigate the package and feed evidence first, then make a controlled trial correction. Simultaneously changing stitch settings and finishing conditions would prevent the team from knowing which intervention restored the result.

The release entry should name the order, new yarn lot, roll and sample identifiers, accepted settings revision, inspection results and the person responsible for disposition. Distinguish permission to continue a controlled trial from permission to ship commercial fabric. Pending laboratory or finishing evidence cannot disappear because production needs the machine for another order.

If a result fails, identify the earliest potentially affected interval and segregate related rolls. A repeat sample after correction establishes a new boundary; it does not retrospectively approve earlier fabric. At shift handover, make the package map and the latest disposition visible together. Close the changeover only when the next operator can identify approved replacement yarn, excluded transition material and the settings that produced the accepted sample.