Tests for Potting Compounds

Are you potting in house or is someone doing it for you and supplying you a complete potted electrical part?

Hi, We are potting in house

Thanks,

Well you can start with inspection tests of the sample to ensure it matches the consistency, colour, strength, etc that you expect. If applicable I would also try destructive testing by removing the potting to test its mechanical strength and to see if it is bonding to the board, if the potting material has any voids, etc.

If you are concerned about the new potting product and/or its mixing and setting characteristics you could monitor the potted product batches that come in to ensure good quality control. Perhaps a weigh test if the product is large to check for voids due to incorrect potting compound degassing or void filling on your potted equipment.

In the end it is important that the potting compound is mixed correctly and a clear manufacturing and test procedure in place for potting the boards so it is done right first time, along with rigid quality control to ensure that your supplier keeps on producing potted boards the same quality as the first samples. In my experience most of the quality control problems with potting materials are with surface preparation, humidity, incorrect compound ratios, incorrect mixing, incorrect degassing, etc. Unless you potting compound supplier has very bad batch control, is supplying expired potting compounds, or the potting compounds have spoiled due to improper storage, then any problems will likely be due to how you use the potting compound.

Further specific information and guidelines can be found in the potting compound manufacturers data sheets and usage and application documentation.

Can we do any simple test even if it is destructive to demonstrate the suitability.

more importantly hardness comparison.

Thanks for comments and suggestion.

What tests were you doing previously?

Hardness testing depends on the hardness of the potting material and can be as simple as applying a known force or pressure to the old and new potting compound samples (such as a known weight on a centre punch or a known weight dropped from a known height) and seeing if the material cracks or separates entirely from the product. Similar tests can be repeated by heating the samples in an oven to the expected operating temperature they will be subjected to (some potting compounds will soften at a high temperature). Abrasion testing can be done with a file or (carefully) with a knife (depending on the potting material) to test potting compound strength and consistancy.

Another really simple test is to carefully cut the potting material off (knife or fine blade saw) and inspect for voids, gas bubbles, correct bonding to the equipment being potted, air voids, etc.

Perform some tests on your old potted board and then repeat the same tests on the new potted board to see if the new material has the same or better properties.

For more detailed testing refer to the data sheets and try to simulate the conditions the potted equipment will be subjected to. There are standards you could test to (covering mechanical and electrical properties), but I think this is outside the scope of what you are after.

Oh, and one more very important thing, carefully check the data sheets and application data sheets to ensure that the new potting material is suitable for potting electronics. Some (like building and paving potting materials) are NOT and could attack the board and components causing premature board failure. If in doubt consult the potting compound manufacturer directly to ensure suitability, they will know which ones are suitable.

What <...tests...> are being carried out today on the <...reputed manufacturer's potting compound...> and where is it failing them?

What discussions are underway with this <...manufacturer...> with a view to correcting them?

Surely the testing for a new <...manufacturer's potting compound...> would need to satisfy more criteria than the existing one is currently achieving?

Otherwise, why <...switch over...>?