Electronics Forum | Thu Dec 07 03:21:54 EST 2006 | Guest
Materials you see are corner bond adhesive, main purpose of this is mechanical shock absorber , it promotes additional adhession to lessen stress to solder joints incase device subjected to mechanical stress like dropping.By function, corner bond
Electronics Forum | Wed Dec 06 21:59:37 EST 2006 | SMTrework
Hello, we rework BGA packages that come back from the field. I've seen on occasion a black and or red "epoxy" substance from the manufacturer on the corner of some board's BGA chips that I imagine are applied to increase corner bond of the chip to th
Electronics Forum | Thu Dec 07 19:54:55 EST 2006 | davef
We agree with "guest" above. This a "chip bonder" type material used to improve the reliability of array type devices. "A relative comparison of the N50 values is given below: No underfill = 1.0X (baseline) Corner bond = 1.3X Non reworkable underfi
Electronics Forum | Thu Dec 07 14:17:03 EST 2006 | russ
I would bet that it is a SMT adhesive used to ensure that the BGA does not move during a secoindary reflow prcess. this glue is easily removed with a soldering iron. Russ
Electronics Forum | Wed Dec 06 22:46:39 EST 2006 | SMTrework
Hi Dave, This is manufacturer applied epoxy / adhesive to minimize package "lifing" from chassis flexing and thius board flexing. I have seen the complete array area covered with this black or red epoxy in some cases (i.e. the underfill that I've
Electronics Forum | Thu Dec 07 12:18:28 EST 2006 | realchunks
It may be for a double sided reflow process. Yes, some people do put the BGA on first. I know this first hand.
Electronics Forum | Wed Dec 06 22:35:05 EST 2006 | davef
Questions are: * When you say, "corner of some board's BGA chips", is it on the top of the package or between the board and the bottom of the package? * If between the board and the bottom of the package, does it span the distance between the board a
Electronics Forum | Fri Apr 30 11:55:55 EDT 2004 | Chris Lampron
Hello Fredrick, I have used several methods of TC attachment including quick set adheasives (not good at reflow temps as Dave suggests) long set two part epoxies (work well if you have the time to wait for a sufficiant cure) temprobes, tape (kapton
Electronics Forum | Tue Apr 02 22:58:10 EST 2002 | davef
Whatever I've said, my intent has never been to insult you. Smack you yes, insult you no. True, you never said the word �strings� but you did say � * �� shouldn't I be able to expect enough green strength from my epoxy to hold 0603 caps in place wi
Electronics Forum | Fri Apr 30 08:28:39 EDT 2004 | davef
Roger Saunders, President Saunders Technology, Inc wrote a fairly unbiased paper that compared different thermocouple attach methods. You can probably find it on their site. In it, about gluing thermocouples, he says: There are two general classes
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