Detection Of Uncured Material In Lower Layer Of Potting

Single part or two part potting?

Heat cure or room temp cure?

What is the relative humidity in the room?

How thick is the pour?

My guess is single component (one part) room temp cure in low humidity room, poured in too thick a section.

I'm not aware of any easy method to check degree of cure.

ASTM- D913 & http://ponderosapaintco.com/techdata/8.pdf

Ultrasonic should do it, but not simple.

If you could tap the housing, you might find the 'ring' to be of a higher frequency when cured.

Or vibrate it at (resonance?) & measure the power consumption. Cured should be min power.

Or do ten samples, cut open at certain intervals, then double the time you find the first full cure.

We have cubical housing of polyamide 66 which is filled with potting material for isolating PCBA. We want to detect the cases of uncured material remained in some spots which cannot be identified with any test. We don't want our PCBA dameged during process. If ultrasonic is possible how it can be implemented. For cubical housing and approx. Cost of setup.

The fact that the seemingly uncured material is below the surface, in the bottom of the "cubical," should be an indication that air, or moisture needed for cure, is not penetrating the material fast enough to suit your requirements.

Ultrasonic energy may speed the cure and render the test moot.

Without more pertinent information solutions may evade you.

Actually we analysed the failure it is found that root cause of problem is due to resin and hardener ratio was out of tolerance limit. The MMD machine caused off ratio mix. But we are trying to deploy test to detect such cases and it is one in thousands case. Only one such case found untill now but it is very severe failure.

That would have been good to know in your original posting.

Up the hardener until it goes off too quickly, then back off till it almost does.

& fix your MMD machine & mixer?

Apply a load test -it will only be destructive to the bad ones?

GA.

Do you know how to sort hard boiled eggs from uncooked eggs. Just spin them on a smooth horizontal surface: the cooked eggs spin as you'd expect, but, the uncooked ones are very difficult to spin. Adapting this technique with very careful measurements of torque and turntable speed may provide an answer.

X-rays?