Electronics Forum | Tue Jun 28 07:27:32 EDT 2005 | Matt Kehoe
We are experiencing a situation that we would really appreciate some expert opinions on. Our process prints solder paste then reflows it without components. Normally the paste wicks into a very shiny rounded meniscus. Even over gold, the round pads a
Electronics Forum | Tue Jun 28 18:20:49 EDT 2005 | russ
Matt, have you run a profile on this board? Just because it's .062" doesn't mean that any old .062" profile will work. We have .062" thick boards that almost nil for copper and other are utilizing 2 oz. layers internally. They require quite diffe
Electronics Forum | Thu Oct 21 17:05:11 EDT 2004 | davef
While it's not exactly what you asked, it's similar. Here is a thread from the fine SMTnet Archives from a couple of weeks ago, where we spoke about the topic of mixed lead-free solder with components that have lead-bearing solderability protection:
Electronics Forum | Wed Jun 29 06:57:20 EDT 2005 | mattkehoe
Hi Bob, We tried flowing the pads with a soldering iron. The pad at the tip of the iron went shiny but as soon as the iron was taken away, the pad returned to the dull finish. You could actually move the tip around the pad and it would shine up then
Electronics Forum | Sun Jul 10 12:42:15 EDT 2005 | IMRANH
HI I am IMRAN i am not expart for it but i tell you one thing you cheak your PCB in microscompe may bee posibal you can see veary thin lear on the pcb pad. its come from pcb monufacturer whan they pass form chmical solution its lear may bee com. pl
Electronics Forum | Wed Jul 12 11:46:00 EDT 2006 | flipit
Hi, One other note. You don't want gold to be more than 1% to 2% of the the solder joint. Above this percentage you will have embrittlemant issues. Lots of information on gold embrittlement on this site and on the Internet. I estimate your produ
Electronics Forum | Fri Feb 28 08:48:00 EST 2020 | SMTA-Joe
We've made the decision to move towards Gold Immersion on our PCBs to eliminate flatness issues with QFNs and BGAs. Land/component pad geometry, population density, and other factors, have made it necessary to ensure a near perfectly flat surface tha
Electronics Forum | Tue Jul 11 20:13:05 EDT 2006 | davef
We agree with Chunks. You need to turn-up the heat [slow the conveyor] because you have significantly changed the melting point of the solder alloy by adding so much gold. Relative to ENIG you should expect: * Similarly smooth surface, possibly a l
Electronics Forum | Wed Jul 12 11:26:12 EDT 2006 | flipit
Hi, I believe you have classic gold imbrittlement here. With 80 microinches of gold you are way over the limit. You can try to reflow longer time and at a higher temperature. The gold does not melt into the solder joint. The gold dissolves into
Electronics Forum | Tue Jun 28 16:41:07 EDT 2005 | mattkehoe
Yes, .062 fr4. Like I said before, we run a lot of gold boards, as many as 25% of what goes through the shop, and we've never adjusted anything before??? Many of these are bigger by 2 X and much more dense. Reflow is not as shiny as HASL but always u
