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 | Mon Jul 16 14:48:16 EDT 2001 | mparker
Just received "Circuits Assembly", July 2001 issue. An article regarding solder balls and aperture design, beginning on page 40. This DOE had aperture, reflow profile and no clean pastes (3 types) as attributes. It is advocated that a U-shaped a
Electronics Forum | Thu Jul 12 20:50:37 EDT 2001 | davef
One possible reason no one brought-up "too much paste" is that suggestion has been proffered so many times that it�s in the archives like the layers of sediment making-up Kataden. Another thing [we can argue about this], using home plate apertures w
Electronics Forum | Fri Jul 20 17:09:10 EDT 2001 | davef
Circuits Assembly magazine 09/99 "Defluxing with Ultrasonics" by Les Hymes. [There's more but I can't find it right now. I'll add to this as I find the junk, er very nice stuff.] J-STD-001C states that its OK to use ultrasonics for cleaning so lon
Electronics Forum | Tue May 11 15:52:03 EDT 2004 | Erhan
It's been 10 years since I started to use this editing method but never knew that it was called wendy-house style. :-) This is most probably the answer you're looking for if you're only having problems around the 1206 types. For QFPs, I used to redu
Electronics Forum | Wed May 12 07:53:28 EDT 2004 | solderpro
Lets make it easy on the poor guy, some are correct, check you profile but remember one thing most do not apply, it is important to match the type of paste you are using with the style of oven and configuration. send a direct email and I will give so
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 | 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 Feb 08 09:07:22 EST 2001 | Hussman
OK, without knowing the specifics, why does everyone blame the oven? Most solder balls occur around R's and C's in almost every shop I've been to. The best place to start looking is the screen printer - not the oven. Sure the oven is the last proc
Electronics Forum | Wed Feb 07 21:56:00 EST 2001 | davef
Every critter out there with large incisors adapted for gnawing and nibbling has a different theory of solder ball formation. [My theory: It�s punishment for using NC fluxes. Stand and deliver. My solder balls end-up in the gross filter connected
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