21:57 Feb-02-2010 aldo Engineering Italy, Joined Jan 2009 39
clean methods TAM PANEL
Hi all expert on this forum... I came back on one question important for me and important for next NADCAP audit....
I am processing the new TAM PANEL... They are five and are polish and great blast....The pentrant liquid is ID4 and when i used this penetrant i must see five artificial defect .....but often i see only the first four stars and i do not see the smallest stars...I tkink that the small stars is clogged by powder or residual penetrant... So, the method to clean TAM PANEL is ultrasonic cleaning by acetone but it can not to remove the residual material into five stars...I think that the acetone does not enter into five stars and the ultrasonic method it is not effective for this application...Can you suggest me another method of clean to remove eventually material residual so i should see the five stars?
After cleaning the TAM panel, but before processing it, check it under UV light for retained fluorescence, especially in the "stars". (I assume it is one with real cracks and not the spark-eroded version). This check is a specification requirement in most cases.
If there is retained fluorescence, then your cleaning is not adequate. If no retained fluorescence, then your cleaning should be adequate.
Do you work in a "hard water" area where minerals can deposit on the panel when drying? If so, final rinse with demineralised water before drying will help here.
Your TAM panel is an overall system check, and only if your system is correctly controlled will the test results be consistent. If you have inconsistent results (sometimes 4 stars, sometimes 5 stars), this suggests that your system is not adequately controlled.
Do you always use the same TAM panel for the same process? This is a requirement in all specifications that I know. (Not all TAM panels are absolutely identical, so some variation will be observed).
As someone who has had quite a bit of experience with TAM panels, let me offer the following for your consideration. With all due respect to one of the contributors to this forum, the premise that TAM panels can detect system degradation is highly suspect. Please refer to my February 2009 Back to Basics article in Materials Evaluation, where I abused the process with very little effect to the panel. This panel is great for picking up panel degradation only, not material or system degradation. http://www.asnt.org/publications/materialseval/basics/feb09basics/feb09basics.htm
Cleaning the panel with acetone in an ultrasonic cleaner is the best, but it puts out flammable fumes. Venting it takes care of the fumes problem. Cleaning with Lime-Away helps as previously noted. Coating it with non-aqueous developer and baking it in the drying oven helps. Coating it with Ely's Replica Transfer Coating works well. Soaking it in Oakite 990 at 160 degrees F for one hour is a great deep clean as well.
Even better, invent a panel that is capable of detecting system degradation and is easily cleaned. Then you can retire and not have to go through a Nadcap audit.
tanks for your suggestion... but if you speak me some information on lime away because i do not unterstand what it is because i am italian and i do not found the perfect translate in italy....
tanks and best regards...
Lime-A-Way is something we buy at a Walgreens or Wal Mart:
CLR (Calcium Lime Rust) works as well:
Lime-Away is a product that is used for removal of rust and calcium deposits at home. This product is at all of our hardware stores for home consumtion. This is a widely used product for all in the U.S.A.
If I understand correctly, it appears that your panel is capable of producing the required 5 stars. Not all panels are capable. Also, Nadcap requires a system baseline be established with degradation checks.
I have had good luck with alkaline clean in warm water with occasional ultrasonic cleaning, followed by storage in acetone or alcohol. It is recommended to not exceed 93 deg. C (200F) anytime and to not cool rapidly.
One other thing not already mentioned is that cleaning should be performed as soon as possible after use. I have witnessed panels left to be cleaned later and then they are more difficult.