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569 views
00:38 Jun-19-2002

Christophe Mattei

Consultant
Exova AB, NDT Dpt.,
Sweden,
Joined Jan 2001
8
Wetting of polymer to avoid airbubbles indication with US inspection

Hello,

I'm looking for info on ways to improve the wetting of polymer (more specifically explosiv plastic) in order to avoid false indications coming from air bubbles while scanning the part with ultrasound. Any reference or comment appreciated!

Chistophe Mattei
CSM Materialteknik AB



 
05:20 Jun-19-2002

Tom Nelligan

Engineering,
retired,
USA,
Joined Nov 1998
390
Re: Wetting of polymer to avoid airbubbles indication with US inspection : I'm looking for info on ways to improve the wetting of polymer (more specifically explosiv plastic) in order to avoid false indications coming from air bubbles while scanning the part with ultrasound. Any reference or comment appreciated!

First, I assume that the bubbles are clinging to the surface of the material rather than outgassing from it. Also, I assume that you are using de-aerated water (or water that has been standing for a day or so) to avoid outgassing from the water.

I have no specific experience with scanning explosive plastics, but as a general suggestion, we sometimes use a very weak soap solution to break up surface tension when bubbles are clinging to the surface of a textured specimen. That minimizes the tendency of bubbles to cling to a surface. Just wet the surface of your test material with the solution before you put it in the test tank. Note that the concentration should be weak -- typically a couple drops of liquid soap in a liter of water is sufficient to break the surfacetension.

--Tom Nelligan
Panametrics, Inc.


 
06:10 Jun-19-2002

David Hermanutz

Consultant,
Hbndt.com,
China,
Joined Jul 2012
85
Re: Wetting of polymer to avoid airbubbles indication with US inspection : : I'm looking for info on ways to improve the wetting of polymer (more specifically explosiv plastic) in order to avoid false indications coming from air bubbles while scanning the part with ultrasound. Any reference or comment appreciated!
.
.
: First, I assume that the bubbles are clinging to the surface of the material rather than outgassing from it. Also, I assume that you are using de-aerated water (or water that has been standing for a day or so) to avoid outgassing from the water.
.
: I have no specific experience with scanning explosive plastics, but as a general suggestion, we sometimes use a very weak soap solution to break up surface tension when bubbles are clinging to the surface of a textured specimen. That minimizes the tendency of bubbles to cling to a surface. Just wet the surface of your test material with the solution before you put it in the test tank. Note that the concentration should be weak -- typically a couple drops of liquid soap in a liter of water is sufficient to break the surface tension.
.
: --Tom Nelligan
: Panametrics, Inc.
.

You may also want to consider the chemical effects of the liquid soap on the material you are testing, I'd hate to start a chain reaction considering the material you're on ;)




 


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