Seam Defect Guide
Comprehensive reference for double seam defect identification, root cause analysis, and corrective actions. Focused on Angelus seamers and beverage can production.
Wrinkles
Wrinkles appear as folds or pleats in the cover hook area of the double seam. They indicate insufficient tightening during the second operation and can compromise seam integrity, allowing potential ingress of contaminants or loss of hermetic seal.
Wrinkle rating is measured on a scale of 0–5 (or 0–100% in some standards). A wrinkle rating above 25% (or grade 2) is typically considered a defect requiring corrective action. Wrinkles form when the cover hook is not sufficiently ironed during the second seaming operation.
- 1Second operation seaming roll worn or improperly profiled
- 2Second operation roll pressure too light (insufficient chuck-to-roll gap)
- 3Seaming chuck worn or out-of-spec diameter
- 4Excessive first operation roll pressure creating an over-tight first seam
- 5Lid compound too thick or improperly cured
- 6Can flange height out of specification (too short)
- 7Seaming chuck not fully engaging the lid countersink
- 8Worn or damaged seaming chuck drive key
- 9Incorrect second operation cam profile for the can diameter
- Visually inspect cover hook area under 10x magnification
- Assign wrinkle rating per CISA or plant standard (0–5 scale)
- Measure seam thickness — excessive thickness indicates under-ironing
- Check cover hook length — short cover hook often accompanies wrinkles
- Measure seam width (height) — verify within specification
- Perform cross-section teardown and inspect cover hook fold quality
- Check second operation roll profile for wear or damage
- Verify seaming chuck diameter with go/no-go gauge
- Tighten second operation roll (reduce chuck-to-roll gap by 0.001"–0.002" increments)
- Replace worn second operation seaming roll
- Verify and adjust second operation cam timing and profile
- Check and replace seaming chuck if worn below minimum diameter
- Inspect first operation seam — if over-tight, back off first op roll slightly
- Verify lid countersink depth and flange curl are within spec
- On Angelus 60-series: check second op roll eccentric adjustment and lock
- Review lid supplier specifications — confirm compound weight and placement
On Angelus seamers, wrinkle issues are most commonly traced to second operation roll wear or incorrect eccentric adjustment. Use the Angelus roll setting gauge to verify second op roll gap. Check the chuck drive key and keyway for wear — a loose chuck will not iron the seam consistently. Refer to Angelus Service Bulletin SB-2200 for second operation roll adjustment procedures.