Hi ESD Experts,
good day.
have some questions on material testing to ESD. I have my controlled cabinet, and I precondition my material for testing both low and moderate RH. my question is, is it ok if I take out the material outside the cabinet and then test it or does the standard require that the material be tested inside while maintaining the low or moderate RH.
Any advise is highly appreciated.
thank you.
Rosalie,
The standard test methods require the testing be done in the environment. That is why most qualification testing is done in a glove box or walk in chamber. I am not sure how much the results would be changed if the tests were done immediately after removing them from the controlled environment. I am sure the standard test methods were set up this way to obtain more consistent results
Dear AndyN,
thank you for your reply. if i have a material tested on both conditions (outside and inside after precondition) and found correlated, will that be acceptable base on the requirement of S20.20?
thank you for your advise.
Rose,
If you tested the material both inside and outside the environment after pre-conditioning, then you would meet the standard because you did the testing inside the environment which is what is required.
If you are trying to say that because I have a certain ESD control item that correlates between measurements inside and outside the environment, I can now test other ESD control items outside the environment, I would not necessarily agree. You may find correlation in some ESD control items but others may not. I think the biggest factors that could lead to it not correlating would be the susceptibility of the ESD control item to absorbing moisture and changing temperature as well as how long it takes to do the measurement. Thanks
Good morning Rose,
I agree with Andy that you should be cautious in how you conduct your testing. Remember that and ESDA approved Standard Test Method (STM) is a definitive procedure that has been verified by multiple independent laboratories for the identification, measurement, and evaluation of one or more qualities, characteristics, or properties of a material, product, system, or process that yield a reproducible test result.
While some of your results may correlate, they may not be exactly reproducible if the STM procedure is not followed as written.
Dear Matt and AndyN,
i see. i totally agree on you both. i missed to consider that some materials have different property esp in moisture absorption.
thank you very much.