A sealing land is the surface that contacts the mating seal. A narrow scratch or raised line can blend into the surface when the light runs along it. Changing the light direction can make the same mark easier to see through a highlight or shadow. A broad light and an oblique light are useful for different parts of the inspection.
Track the mark relative to the part
Identify the actual contact surface from the drawing or a verified assembly. Inspect it under the first light direction, then change direction without moving the sample. Note whether the mark is within the contact band and whether it crosses that band or runs along it. Compare a clean reference and keep the original surface intact before trying a cleaning check.
Verify the sealing question separately
A visible mark helps determine where to look, but it does not establish a leak path. A flexible seal can respond differently to a shallow groove and a raised piece of debris. If the mark is within the contact area, check the matching closure and sealing performance using the agreed package test. Preserve photos from both lighting setups with the sample record.
Packaging sample showroom of SamBound New Material Technology Company Ltd. Company information: sambound.com.
SamBound New Material Technology Company Ltd.