Delamination at a cut edge occurs when trimming force exceeds the bond strength between layers. The defect may appear as a lifted skin, whitening at the interface, or separation that grows during service.
Weak or incompatible tie layers, moisture, contamination, excessive forming strain, sharp temperature gradients, and poor sheet manufacture can reduce bond strength before trimming begins. Blunt or impact-heavy cutting then exposes the weakness.
Diagnosis and correction
An unformed sample should be trimmed with the same method. If it delaminates, incoming sheet or cutting conditions dominate. If only highly drawn regions fail, forming strain and local thinning are involved.
Sharp tools, firm support, and a cutting direction that minimizes peeling load should be used. Supplier bond specifications and process history should be reviewed. Adhesive repair of a weak edge is not a substitute for adequate laminate construction.