Electronics Forum | Wed Oct 11 21:55:27 EDT 2017 | action_101
I've used plenty of weights in the wave solder process, but not in the SMT reflow process. Ask yourself some why's.... such as why is the part lifting at one end? (board bowing possibly), why? Not the correct tg material or issue with oven profile? W
Electronics Forum | Thu Jan 19 20:40:52 EST 2006 | Gary Kemp
We are experiencing a blistering problem during our process of lead free assembly. The customer has supplied us with the bare fab rated at 140 Tg. I am under the assumption that the Tg rating should at minimum be 170. Does anyone know if there is
Electronics Forum | Thu Jan 19 21:43:33 EST 2006 | davef
Specifically, what element of the bare board is blistering? Tg of 140 could be acceptable. Search the fine SMTnet Archives for background on decomposition temperature [td]
Electronics Forum | Mon May 13 23:44:26 EDT 2019 | dami0629
if use tray cannot solve the problem, you can change from the design 1）Reduce the effect of temperature on PCB 2) PCB USE HIGH TG 3) BOARD THICKNESS TOO THIN 4) MODIFY THE BOARD SIZE 5) Reduce the V-CUT depth.
Electronics Forum | Mon Mar 13 22:29:50 EST 2006 | davef
Warp depends on: * How close the board gets to its Tg during the reflow cycle (the closer you get to the Tg the worse the warp gets) * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * T
Electronics Forum | Mon Oct 03 22:12:53 EDT 2005 | davef
When we see warp and twist, we usually jump the fabricator for: * MLB construction (not homogeneous or unbalanced - too resin rich or poor) * Supplier process capabilities (lamination cycles) * Material selection (usually cheap and dirty), etc. War
Electronics Forum | Mon Dec 31 08:51:58 EST 2001 | davef
Warp depends on: * How close the board gets to its Tg during the solder cycle (the closer you get to the Tg the worse the warp gets) * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * T
Electronics Forum | Tue Aug 08 20:43:41 EDT 2000 | Dave F
Tom: So is warp or is it twist? They�re different problems, possibly with different sources!!! And possibly different solutions!!! Consultants to talk to are: Earl Moon (pod@vcn.com), Werner Engelmeyer (engelmaier@aol.com), Les Hymes (les.hymes@w
Electronics Forum | Wed Jun 26 08:53:32 EDT 2002 | davef
We have not done a DOE on board warping. Consider: * How close the board gets to its Tg during the reflow cycle * Amount of copper on each side and the balance between the two * Thickness of the board * Overall length x width * Time at temperature
Electronics Forum | Wed Nov 17 09:02:57 EST 1999 | Dave F
John: The 180 Tg point is a sweet spot for obtaining heat resistance, cost effectivly. These high technology boards provide good thermal resistance for wire bonding, direct chip attach, and BGA mounting and rework. Since these boards are harder th
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