Electronics Forum | Wed Sep 15 20:59:23 EDT 2010 | genesan
hi All, Here i snap shot previous PCB(HASL) and current PCB(Immersion Silver).Base on the photo it could be PCB oxidize cause the non wetting?
Electronics Forum | Tue Sep 14 04:00:12 EDT 2010 | genesan
Hi Sir grahamcooper22, There should not a issue in stencil since i had open the aperature 1:1(one to one).Futhemore this is HASL pcb coating as now our customer had convert to immersion silver.I had do comparison between both and found HASL wetting n
Electronics Forum | Tue Sep 14 14:07:45 EDT 2010 | grahamcooper22
Hi Gani, HASL is normally very good for solderability providing there is a good consistent coating of HASL on the pcb pad. But it is not unusual to have a very thin coating of HASL on the pad and this is poor for solderability. You then have tin/copp
Electronics Forum | Sat Sep 20 07:11:28 EDT 2008 | Sean
Hello All, I used to hear that PCB with immersion silver finishing, its non component location pads, tend to be discolour (Yellowish) after went through heat cycle, such as reflow oven. However, if the component solderbility on the PCB is OK, can w
Electronics Forum | Mon Sep 22 15:32:20 EDT 2008 | davef
We see this fairly often. It doesn't affect solderability. Our analysis makes us think this coloration is copper. The reason copper appears on the surface may be that heat cycles increase the thinness and porosity of the immersion silver [IAg] coatin
Electronics Forum | Thu Sep 16 01:54:46 EDT 2010 | sachu_70
Hi Gani, Immersion Ag finish has lesser shelf life as it can get more easily oxidized on exposure. However, I see concern in your Reflow profile. A few questions: Have you compared your reflow profile to the solder paste manufacturer's recommended pr
Electronics Forum | Fri Aug 30 16:25:21 EDT 2002 | davef
Imm silver holds-up to multiple thermal cycles very well. The things, we guess, are happening to make imm silver tough to solder after heating and sitting are: * Oxidation of the silver. * Reduction of the co-deposited organic anti-tarnish [used in
Electronics Forum | Thu Dec 14 10:14:04 EST 2000 | PeteB
Jacqueline, Asuming you mean immersion silver: Advantages - Very flat finish compared to HASL, more easily solderable than bare copper with OSP and more process tolerant than this in our experience, reasonable shelf life, cheaper than immersion gol
Electronics Forum | Fri Apr 29 14:16:16 EDT 2011 | ppcbs
Below is the long explanation. This defect is most commonly found with BGA components, but can arrise with all components. I see it happening more now with lead free boards that are being assembled with a no clean flux. Best short term remedy is t
Electronics Forum | Mon Jun 18 10:20:14 EDT 2007 | ck_the_flip
Grant, i have heard of a few cases where the PCB is "reworked" by the PCB house, where the immersion silver that did not wet to the base copper was reworked by just putting immersion silver on top of the non-wetted immersion silver. I know your PCB
