I´m working at moment in inspections of holes with Eddy current ( Rotary Scanner ). I have had many problems during the inspections in edges and layes interfaces in materials.of aluminium and steel I want to find information about the inspections of eddy current with Rotary Scanner. Somebody can help me with the following topics:
1. Filter adjustments for a good inspection. 2. Signal evaluation to be able to distinguish the crack indications from other variables. 3. Causes for indications that may be confused with cracks 4. General information about inspections with Rotary Scanner
12:21 Oct-07-2017 John Hansen Director, - Eddy Current Technology ETher NDE Ltd, United Kingdom, Joined Oct 1999 71
Re: Inspection of eddy current with Rotary scannerIn Reply to John at 02:09 Oct-07-2017 .
Boeing are about to release a new NTM for rotary hole inspection and Airbus have a pretty good NTM already.
1) The usual requirement is to set the LP filter 2.5 to 4 times higher than the HP and using a notch in a hole (or the Airbus type split standards) then set the notch response vertical and adjust the HP filter until you get a W on the time base (height of 2 negative parts equal). I understand some ec equipment cannot do the filter optimisation well owing to using incorrect types of filters.
2/3) cracks should be similar to the notch but rotated clockwise. Mechanical damage and corrosion rotated anti clockwise. Ferrous shims can give a very odd signal bit will not look like a notch or crack.