Electronics Forum | Mon Dec 18 16:13:15 EST 2006 | darby
AJ, No overprint. We have components in very close proximity that precluded that. Also we have differing areas of thermal relief for the pads from a large backplane, from none at all to open blocks to individual pad relief. After a few more experimen
Electronics Forum | Mon Dec 16 10:54:48 EST 2002 | davef
Knee of barrel and pad crack: Caused by thermal stress during soldering, because epoxy expands in the "z" 3X more than "x" or "y" which are restricted by the fiber. Related to: * Design of pads too large relative to hole diameter * Temperature at o
Electronics Forum | Tue Aug 25 16:28:11 EDT 1998 | Al Knudson
Hello, Our PWB supplier has requested that a change in the laminate material to reduce the incidence of pad lifting. The standard laminate materials (Polyclad PCL-FR-226 with a glass transition temperature of 135 C) have greater z-axis thermal expan
Electronics Forum | Fri Oct 11 09:28:14 EDT 2002 | davef
Designers love to do BIG copper pours for several reasons: * Maximize heat spreading. * Increase EMI shielding. * Laziness. The poor folk that solder the parts on boards HATE big copper planes near solder pads. During soldering, fat copper traces [
Electronics Forum | Wed Jun 08 17:35:04 EDT 2016 | slthomas
We all know that whenever possible, we want thermal relief between the barrel/pad and the copper foil to make it easier to properly solder that through hole connector. My question is, assuming there is no connection from the barrel to a copper layer
Electronics Forum | Fri May 31 12:50:42 EDT 2013 | spoiltforchoice
Is this a "thermal balance" issue? In the 2nd image you have a group of pads blobbed together as one giant pad. IMHO this is a bad idea, QFN's rely heavily on the magic of your paste and good PCB design to get good alignment. When your solder paste i
Electronics Forum | Tue Apr 10 02:57:53 EDT 2018 | rob
Yes I would, most of our old Yamaha machines (before 2005) will do 30-35 microns @ 3 sigma with the fine camera option. Our Jukis with His res camera's will hit it too. You should be OK with most things after 1997 with the right camera choice (whic
Electronics Forum | Tue Jan 14 11:53:44 EST 2020 | avillaro2020
Hi Phil, thanks. I am successful using the same connector on small thinner boards 2-2.5kg) i cant make it work, tried all kinds of profiles with vapour phase but to no avail. Yes you read it right 4.3-6.3mm pcb thickness and 2-2.5Kg. And it is 44 lay
Electronics Forum | Fri Dec 17 08:45:26 EST 1999 | Wolfgang Busko
Hi Henry, amoung all things that cause this funny effect the most effective measures in my experience were good PCB design (pads and equal thermal conditions for both sides of the components), placement accuracy and profiling, profiling, profiling. L
Electronics Forum | Thu Feb 10 09:08:21 EST 2000 | C.K.
We've got this hard-to-Wave-solder board where all of the SMD's are on a ground plane - in fact the entire bottom-side is a ground plane. Our designers have incorporated thermal relief on some of the pads, but for reasons unknown to us, they don't h