Electronics Forum | Fri Jul 06 03:23:01 EDT 2001 | kennyhktan
Hi there Steven ! Please allow me to share some of my problem we're facing here with you. Here are a few points that I suggest you should check on your current process:- (1)PCB - Component land partern design ? It is per IPC spec ? - Mask
Electronics Forum | Thu Feb 14 17:40:34 EST 2013 | jorge_quijano
PCB Supplier made an EDX anaysis, the found a chemical trapped in the holes, and some burnt burrs, according to what they say this stains are over the solder mask & silk, so they do not affect functionality.
Electronics Forum | Fri Jan 25 14:20:31 EST 2013 | jorge_quijano
Hi there, I have a new product today, after reflow oven I've seen a black stain coming from various holes, they can be cleaned with a tissue but some of the contaminant remains inside, we are using Sn63Pb37, the stains are far from soldering areas, t
Electronics Forum | Fri Jul 06 04:02:28 EDT 2001 | eliishee
Thanks guys for all the input. i'm still struggling to find out the main cause. at time being, urgently need a suggestion of a effective way to remove all these solder balls. THANKS AGAIN.
Electronics Forum | Mon Jul 16 21:29:03 EDT 2001 | davef
Cleaning RMA with water is bad news. It will turn your solder connections white and remove none of the RMA residues. There was a thread on removing RMA within the past two weeks on SMTnet. Check the fine SMTnet Archives. Additionally, look at M
Electronics Forum | Mon Jul 16 15:49:33 EDT 2001 | Steve
The solder balls you are talking about are caused by too much paste. Reduce the size of the stencil aperatures. Concerning removing the solder balls, the first thing you need to ask yourself is, do I need to remove them. IPC-610, 12.4.10 states, "Ac
Electronics Forum | Mon May 10 18:43:23 EDT 2004 | steve davis
Just curious what stencil company are you currently using? What style of aperture are you using for the componet?
Electronics Forum | Thu Jul 05 10:45:01 EDT 2001 | dougie
Steven, There is a load of info on this if you check through the archives. Quick pointer though are: Solder balls are caused by paste creeping under the component at placement. The part is placed and the paste is squashed under the component, when t
Electronics Forum | Tue Jul 17 15:13:53 EDT 2001 | mparker
Dave - I agree that the U shape for QFP's sounds a bit whacked, for the reasons you state. It may work OK for larger pitchs but then again there are a myriad of fixes that work before resorting to U shapes. With the U shape removing paste from under
Electronics Forum | Thu Jul 05 07:34:57 EDT 2001 | steven
what is the main reasons that casuing solder ball during reflow? and how to remove them? (mostly arround the connector leads or between the 2 0402 chips). solder paste is RMA type. need advise. thanks
