Noticed while measuring thickness measurements on polyster coatings of different layers.
2007-02-22 17:46:52 · 3 answers · asked by bhathru 1 in Science & Mathematics ➔ Engineering
'Running fluid' Probably not the correct name but its the lubrication you use on the head. If the measuring head is moving there are special lubes with ultra low surface tension these promote better wave transferee. We used a lube which was actually for crack detection heads.
essentially the surface contact is not good enough. Also if you are scanning the film make sure you are not averaging the coating. If you take spot reading then average those you will get a good result where as we found that the average of a the head was way out as it was including spurious readings in the average.
2007-02-22 19:15:40 · answer #1 · answered by Gib 3 · 0⤊ 0⤋
because of the layers. air is entrapped which can lead to erratic readings
2007-02-23 09:22:46 · answer #2 · answered by purimani2005 4 · 0⤊ 0⤋
Check whether your gauge is calibrated (ie ,verified against an authorised gauge).
http://en.wikipedia.org/wiki/Ultrasonic_inspection#Advantages
2007-02-23 02:18:35 · answer #3 · answered by Anonymous · 0⤊ 1⤋