Tri-Ply Circles
Tri-Ply Circle Defects: What Buyers Must Inspect
A defective circle becomes a defective vessel - after you have paid to press, polish and pack it. Catch defects at incoming inspection, where they are cheap.
Defect 1 - Delamination
What: layers separating. Spot it: tap test (hollow ring vs solid thunk), edge inspection, ultrasonic on samples. Verdict: reject the lot - delamination never improves.
Defect 2 - Bond voids
What: unbonded patches inside the sandwich. Spot it: ultrasonic testing on AQL samples. Verdict: reject - voids become blisters under heat.
Defect 3 - Thickness variation
What: gauge drifting across the coil. Spot it: micrometer readings at multiple points per circle, multiple circles per lot. Verdict: reject lots outside your ± tolerance.
Defect 4 - Edge burrs & dents
What: rough blanked edges, handling dents. Spot it: visual + touch. Verdict: minor burrs acceptable if your drawing process tolerates them; dents on the face - reject.
Defect 5 - Surface contamination
What: oil, scale or stains. Spot it: visual under good light. Verdict: usually cleanable - but recurring contamination signals process problems at the supplier.
Your incoming QC routine
Per lot: visual 100% (fast), micrometer + tap test on AQL sample, ultrasonic on 2-3 circles, and a trial press of 5 circles before releasing the lot to production. Thirty minutes that saves weeks.
Frequently asked questions
How do I test for delamination?
Tap test (listen for hollow spots), edge visual inspection, and ultrasonic testing on samples - the reliable trio.
What AQL should I use for circles?
Critical defects (delamination, voids): AQL 1.0 or zero-tolerance. Major (thickness): AQL 2.5.
Have a cookware project in mind?
We manufacture triply cookware and supply tri-ply circles for OEM, private label and distribution. Tell us your specs - we reply with a quote.