[admin]

A witness mark on a closure liner can show where the container rim contacted it. The mark is useful for checking alignment when the expected sealing surface and the assembly conditions are known.

Record the mark before it changes

Start with clean, unused liners and identify the intended contact land on the drawing or approved sample. Close equivalent assemblies using the agreed setting, hold them for the same interval, and open them without dragging the liner across the rim. Photograph the mark promptly. Some materials recover with time, so a late photograph can miss a faint impression.

Record the mark’s position relative to the intended seal land, its continuity, and any local changes in width. An off-center track or a missing segment is a reason to inspect liner seating, rim condition, and the way the closure engages. Intensity alone does not quantify pressure, and marks can differ with material, dwell, or visibility. Compare several assemblies against an approved reference. Run the agreed leak or barrier test separately under conditions representative of the filled product before drawing conclusions about seal performance.

The SamBound packaging catalog is available at sambound.com.

sambound.com
SamBound New Material Technology Company Ltd.

[Author]

Posts