Electronics Forum | Tue Apr 25 18:51:06 EDT 2000 | Steve Thomas
We have quite a few stencils that either are debonding, have debonded, or we suspect will debond when we can least afford for it to happen. The epoxy is coming loose from the foil, but remains attached to the webbing. All the stencils that are comi
Electronics Forum | Tue Dec 19 08:32:44 EST 2006 | davef
Take your choice: * Can't image this is a good thing. The board under the die will 'dry-out' and turn brittle over-time. It's possible the way attachment glue bonds to the board will change as the board dries-out. * Epoxy suppliers pad their number
Electronics Forum | Tue May 02 14:19:26 EDT 2000 | Bill Schreiber
There are two primary causes of epoxy adhesive bond failure, heat and over exposure to moisture. Ultrasonic cavitation is a only a mechanical "scrubbing" action on a microscopic level. However, if the adhesive bond is week or has small areas of det
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 | Fri Jan 21 14:51:08 EST 2000 | Dave F
Mike: I�d hate to see you making design decisions, based solely on the discussion here, but that this would be an impetus to consult IPC-D-279, "Design Guidelines ... " and take a course on designing reliable boards. Werner Engelmaier (Engelmaier
Electronics Forum | Wed Nov 28 07:41:10 EST 2007 | davef
DevGru: Questions are: * What steps do you recommend taking to "watch out for the exothermic heat from the curing?" * What are typical temperatures for exothermic heat from the curing? * What is the duration of such temperatures? * Do epoxy suppliers
Electronics Forum | Wed May 07 09:31:28 EDT 2003 | davef
We use uV Dymax glue for thermocouple attach sometimes, but don't like the remainder [anal] and loosing attach, sometimes. Roger Saunders, President Saunders Technology, Inc; said: PRO: � These products are easier to use than high temperature solde
Electronics Forum | Wed Apr 11 14:05:30 EDT 2001 | davef
No, there's not a really great epoxy product for attaching thermocouples in reflow. Specifically, what's your problem? From Sanders Temprobe verbage ... Adhesives There are two general classes of material commonly used to adhesive bond thermoc
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
Electronics Forum | Tue Aug 09 10:02:07 EDT 2005 | davef
Td or Decomposition Temperature (the temperature that the epoxy actualy starts to break down) should be greater than 330*C for lead-free. Search the fine SMTnet Archives for more on Td.
