Edge delamination where the coating starts to raise off the substrate at a mask line, chamfer or end of a coated band. Common triggers are bridging over tape, square shoulders with no undercut, aggressive grinding toward an edge and high residual stress in thick layers. Once an edge starts lifting it tends to keep going in service, so it is usually stripped and resprayed.
Coating's lifting where the tape came off, that edge has to be stripped, you can't patch carbide.
Also heard as
- edge lifting
- edge lift
- peeling
Related terms
Delamination
Separation of a coating from its substrate or of one coating layer from another.
Bridging
Coating that forms a continuous skin across the edge of a mask, so it tears or lifts when the mask comes off.
Undercut
A recess deliberately machined below finished size so the coating can fill it to full thickness.
Tape
Masking tape used for blasting and spraying, or as a verb, masking a part off before coating.