Electronics Forum: microstrain (Page 1 of 1)

Resonator Cracking

Electronics Forum | Mon Nov 19 21:42:51 EST 2007 | jwsmt

I'll e-mail pics to you. Answers to asumptions: * Flex in end-item use was measured at 410 microstrain * Supplier PPM last 12 mos less than 1 * Part goes through 2 reflow cycles; once on top and once on bottom * ICT microstrain was 1365; reduced to

BGA, stress on the PCB

Electronics Forum | Fri Apr 16 08:20:58 EDT 2004 | Bob L.

We've seen problems with BGA balls breaking at in-circuit test. I did some bend testing and found that our large BGA's can handle amazing stresses at low strain rates but we get brittle fractures at high strain rates, especially with Ni/Au surface f

PWB strain specs?

Electronics Forum | Wed Jul 30 16:57:23 EDT 2008 | stevek

Folks, I'm looking for some specs for the maximum bend or strain that should be put on a PWB. Not looking at the solderjoints. I'm concerned with localized bending of the fab and what might be a reasonable limit for that bending. I've measured 105

BGA open joint

Electronics Forum | Fri Aug 06 08:38:25 EDT 2004 | Bob R.

You don't mention the board surface finish, but BGA's on NiAu are prone to brittle fracture in the Sn-Ni intermetallic on the board side of the joint. You may not be able to see it visually, but it would show up in a cross-section. In-circuit test

pad cratering

Electronics Forum | Wed Jul 01 13:17:39 EDT 2015 | davef

Cheryl Tulkoff and Randy Schueller do a good job summarizing the thinks on pad cratering here: http://www.smta.org/chapters/files/uppermidwest_padcratering.pdf Potential Mitigations to Pad Cratering * Board Redesign * Solder mask defined vs. non-s

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