Electronics Forum | Mon Sep 23 18:11:10 EDT 2002 | steveb
On an assembly reflowed in air saw the same thing: 0201's with a grainular solder joint, but 0402's and above with perfectly formed joints. Reflow profile all within acceptable tolerances. Reflowing in nitrogen solves this problem, but increases t
Electronics Forum | Wed Apr 11 19:32:39 EDT 2001 | Adam
I'm trying to find information/articles describing the effects of temp and humidity on solder paste. Just recently we have gone through a change outside temperature and humdidty and have notice solderabilty problems with smt boards.
Electronics Forum | Tue Oct 22 17:23:35 EDT 2002 | Yannick
Hi, I wondering if someone know the anwser to that. I'm using a solder paste 63/37 and on the solder joint we have a tiny little layer or flux who is like crystalin. I try to play with my profile the get it off but I don't get much success. So D
Electronics Forum | Tue Jan 31 14:23:39 EST 2006 | samir
Chunks, For our lead-free eval, we had the same problem with "charred looking" solder paste up the component termination of one of the smaller discretes, coupled with excessive solder balling...this smaller part did see peak temps in the 240 range -
Electronics Forum | Tue Sep 29 11:49:02 EDT 2015 | spoiltforchoice
Typically - hand soldering as you are currently doing. Should your volume justify it you can invest in a selective soldering solution, these might take the form of a robotic arm that essentially replicates manual soldering or a solder jet similar to
Electronics Forum | Tue Jan 31 12:02:22 EST 2006 | aj
how would you apply both pastes.? anyway, I have succesfully run leadfree bga with lead paste. You gotta find a profile that kinda meets both requirements. Taking into consideration the peak temp and time above. dont have details on hand but I ca
Electronics Forum | Wed Apr 11 22:05:58 EDT 2001 | davef
OA pastes are more hydroscopic than NC pastes. Hydroscopic. The capacity of a material to absorb and retain moisture from the ambient air. Sometimes this is compounded if you remove paste from the frig and let it warm to room temperature, because
Electronics Forum | Wed Nov 06 05:13:01 EST 2002 | Dreamsniper
Crystalline flux if it is really clear should not be a problem. We were using Amtech paste before and we have the same results. Sometimes we mistakenly see it as a dry joint because of the reflections from the lighting of our Metcal inspection system
Electronics Forum | Mon Oct 15 10:51:49 EDT 2001 | davef
On over printing, the general issues are: * Paste deposits being so large that when reflowing, collapse onto many, rather than a single solder mass. * Paste expanding during heating and being close to other solder deposits and bridging [as you say].
Electronics Forum | Mon Feb 19 11:25:07 EST 2001 | markt
I am currently cleaning solder paste and adhesive stencils and misprinted substrates manually by using IPA, chem wipes, Q-tips, etc. Can you recommend a machine and chemistry that will clean all these applications?
