Electronics > Projects, Designs, and Technical Stuff
(ultra)acoustic in circuit component level crack detector?
<< < (6/12) > >>
coppercone2:
also knowledge of impedance units and values in this area will help in designing any sort of test system that is mechanical

i do see merits for RF but if you want to measure like a inductor or diode or something its going to get really hairy, the mechancial method should work in circuit on anything even while powered I think

correct VNA and even ohm setup (range selection) always depends on measurement impedance.




the similar wave behavior of electrical and mechanical system should make this useful to know
rhb:
I don't think that you could get satisfactory mechanical coupling with tweezers on one side of the board.  That also would not detect a solder joint crack between the board and the device.

The correct electrical analogy is a transmission line.  The presence of cracks will attenuate the signal transmitted through the part and the board.

A significant complication is applying enough force to get good coupling, but not so much force that it closes the cracks.  And when I look at the 0.15 mm thick xtals I wonder how one can mount them so they vibrate but not break them.
coppercone2:
maybe rubber bands? a spring should be linear too, you can add one to tweezers
Kleinstein:
Attaching the probes would be a big problem, as too little force would cause poor contact and possible false alarm. To much force could cause the transducers to wear out fast.

With many parts on a board I am afraid individual testing with a contact sensor would be not practical as it takes a long time with manual handling and much wear on the sensors. So if at all it would be something for very high requirements where they can pay something like $10 extra per part for the test.  The more practical test would likely be high resolution X-Ray.

The is some kind of ultrasonic microscopy available already:
https://www.ksisam.com/acousticmicroscopy-en/technology-transducer.php

Depending on the circuit one could also do an electrical test under mechanical load to the board. Some cracks would show up as kind of jumps / spikes.
coppercone2:
hmm if i wanted to experiment further, how would i crack ceramics to make test samples?
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod