Direct answer: a controlled changeover removes obsolete materials and verifies the first finished panel against the new released revision before routine production resumes. It is the practical barrier against a wrong screen, file, coating, label or packing instruction reaching a customer.
What must be cleared
Remove or identify prior glass, screens, files, ink, coating consumables, labels, packaging inserts, inspection references and electronic programs. The goal is not paperwork; it is to make the wrong option unavailable at the point of use.
| Stage | Verify |
|---|---|
| Before setup | released part number, drawing, artwork and route |
| During setup | correct tooling, screen/file, material and orientation |
| First piece | dimensions, print, coating, appearance and label |
| Release | documented approval, segregation and production status |
Use the first piece as evidence
Inspect the first finished part to functional datums and agreed lighting conditions. When relevant, check a powered display or assembly fixture. Factory testing should confirm the component; downstream installation preparation confirms it behaves in the intended stack. Keep the revision and result in the batch record.
The first article guide explains approval evidence; the traceability guide explains how to preserve it through shipment.
FAQ
Is a new label enough to show a new revision?
No. The part, artwork, process, inspection reference and packaging must all be linked to the same released revision.
Must every small change require full requalification?
No. Use documented risk review. A label update and a new coating route do not carry the same risk, but both require controlled release.
Conclusion
Line clearance and first-piece verification give a custom glass program a repeatable reset between variants. They reduce mixed parts without claiming that one check proves every future batch.
Send Tairong your change-control requirements to align the release plan before production.