Electronics Forum | Thu Jan 12 17:35:34 EST 2006 | russ
We use immersion Silver for all of our lead free PCBs. They come in the "silver saver" paper you speak of and we have found that they will tarnish after 7 days in the open enviroment. Even with this tarnish we experienced no reflow problems. We are
Electronics Forum | Tue Jan 24 11:26:09 EST 2006 | russ
We utilize a "keepout zone" around the fiducial that is free of resist, silkscreen, vias, and any other feature. e.g. fiducial diameter of 1mm- we use a 3mm diameter keepout zone. This works very well for us. If the surface finish changes the li
Electronics Forum | Thu Jun 15 09:58:12 EDT 2006 | slthomas
Just to add to what dave said, the only limitation to how frequently you clean is the cost of the cleaning medium. You can wipe every board if you want to, but you'll go through material accordingly. If you're printing 16mil pitch or smaller, cleani
Electronics Forum | Fri Jun 08 18:27:03 EDT 2007 | jmelson
This is probably an inner plated layer of the component that did not bond well. It may be a component that either has the wrong surface finish for lead-free or can't handle the temperatures. Many times I have seen a similar-looking layer when the l
Electronics Forum | Fri Feb 01 10:54:35 EST 2013 | dyoungquist
Regardless of the surface finish, you should try to limit the reflow cycles to 3 with no more than 5 at most. This includes reworking a BGA site as well. Remember that heating/cooling to remove a BGA is one cycle and heating/cooling to place a BGA b
Electronics Forum | Mon Feb 09 07:55:16 EST 2015 | jax
Without knowing the surface finish of the PCB lets focus on an alternative problem... At a minimum, you need to look at the 1/2 built assembly like individual components, all having their own MSD levels and all subject to 2nd side reflow temperatures
Electronics Forum | Tue Apr 26 07:56:12 EDT 2016 | joelperez
Hello SMTnet team, I have read before that silver content on solder joints is ok at around 2% total silver content. Does anyone has experience using SN62/PB36/AG2 BGAs on hard gold (10 micro inches) PCB surface finish? Any drawbacks? Thanks Joel
Electronics Forum | Wed Jan 04 07:32:35 EST 2017 | pavel_murtishev
Good day, Having recieved new batch of PCBs with OSP surface finish, I have noticed that some polygons not covered by solder mask and solder paste become darker after second reflow cycle compared to PCBs not being sent to reflow. I wonder whether i
Electronics Forum | Fri Jan 22 13:22:18 EST 2021 | davidhillman
Hi Graham - brite acid tin gets it "shiny" appearance due to codeposited organic material in the tin plating. The codeposited materials volatilize during the soldering process causing a ton of voids. Brite acid tin plating should not be used as a sol
Electronics Forum | Fri Jan 07 09:03:44 EST 2022 | jineshjpr
Hi Everyone, I want to understand what is the copper thickness to be maintained in PTH Barrel hole. Is this same as Fab recommendation of surface finished copper thickness like 25/35/70 microns..??? Is there any specific IPC standards available to un
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