Environment Stress Screen - Circuit Boards 1

[kaiserman]

To help improve quality, our company will finally set up a Environmental Stress Screen (ESS) for electronic components. I have been involved with durabiltiy for several years. I am now being asked by our manufacturing management to assist the plant in establishing an ESS involving temperature and vibration.

Can anyone direct me where I may find more information on establishing a great ESS?

Thanks!

 

[cab1990]

hello K,

For thermal problems you must look to expansion and contraction of elements of your design which have differing thermal expansion coefficients. These could cause structural stresses which which could for example cause solder connections to fatigue and fail.

For vibration it is best to perform a finite element analysis to make sure that the natural frequency of the board does not interfere with the elements mounted to it. For istance, if an accelerometer was mounted , it could be affected by cross correlation of the board accelerations corresponding to the natural frequency of the board. Other items have their own natural frequncies which must be avoided. In other words, the board must not excite components by matching of natural frequencies.

 

[izax1]

If you take a look at Steinbergs book "Vibration Analysis for Electronic Equipment", he has a chapter on ESS. There is also a paper NAVMAT P-9492 "NAVY Manufacturing Screening Program" that could give useful hints.

It is of course important that your ESS is not "eating up" a substantial part of your product lifetime, but at the same time it should give you a feed back that your system does not have any serious manufacturing faults.

Tricky business.

Regards

 

[pennpoint]

kaiserman

If you can get a copy of MIL STD 810 it may be a big help to your planning and development.

Good Luck
pennpoint

 

[tomirvine]

I have an electronic copy of NAVMAT P-9492.

Send me an Email if you would like a copy.

Tom Irvine
Email: tomirvine@aol.com

http://www.vibrationdata.com