Tap test of Aluminium tap hammer inspection method:
- Scan increment should be no greater than one-third of the allowable damage limit size
- The difference in thickness can cause the tapping sound to change especially at carbon fiber
- On large parts, draw lines on the surface to make sure the inspection area is fully examined
- Taps hammer testing is not reliable on face sheets with more than 3 plies, but tap testing is allowed to determine the extent of lightning strike damage on any thickness composite structure.
- The tapping action must be controlled so that the component’s surface is struck using a light but firm action.
- In areas where there is no delamination or de-(dis)bonding, tapping the component’s surface will produce a clear sound.
- In areas containing delamination or de-(dis)bonding, tapping the component will produce a dull sound.
- NDI inspectors and (certifying)Technicians performing tap testing are advised to do a hearing test.