Electronics Forum | Sun Jun 10 11:31:27 EDT 2001 | nifhail
Everybody aware of the tomb-stone problem on 0402 package. I've done everything I could i.e. Profile, placement, 10 Deg placement, stencil design, but still this culprit exist. One things for sure is taht I have a very bad pad size for 0402 ( 25 mil
Electronics Forum | Fri Jan 14 11:16:45 EST 2005 | Dan Gosselin
I have heard of people using a round pad or Home plate design to decrease the incidence of tombstoning on 0402's Anyone have any practical experience on this or is everyone just using the IPC 782 recommended land pattern (28mil x 33mil rectangle pad
Electronics Forum | Fri Mar 06 02:47:15 EST 2009 | lococost
Have you tried higher peaktemp? I saw the QFP is sn90pb10, This has a liquidus of 268 - 302 C. A good paste should be able to handle 230C (or more), of course you would need to check your other components peak temp.
Electronics Forum | Fri Mar 06 11:01:53 EST 2009 | dyoungquist
I have attached a pdf version of an article that explains the basics of a nitrogen atmosphere when soldering. It gives some basic guidlines as to when one may want to use nitrogen and what it can and can not accomplish. FYI- I did not write that ar
Electronics Forum | Sun Jun 10 12:15:37 EDT 2001 | procon
Hello Danial, Leave it up to most to blame the relow oven for their tombstoning problems when in fact it is usually the last to cause it. The biggest culprit of tombstoning is the pad design followed by the print quality. Usually, we find that the p
Electronics Forum | Mon Jun 18 13:29:34 EDT 2001 | nifhail
What is the recommanded profile for board which consist of 0402 & 0201 comps. to reduce the effect of tomb-stone. Slow ramp rate ? how slow is considered as slow. Soak time 60 or 120 C,at which end should I stick to? what is the best time before reac
Electronics Forum | Wed Jun 20 12:07:13 EDT 2001 | Steve
I would suggest getting a copy of IPC-SM-782A, Surface Mount Design and Land Pattern Standard, and IPC-7525 Stencil Design Guidelines. My experience is that reflow does not cause tombstoning very often. Pad and land design, paste volume, and placemen
Electronics Forum | Thu Oct 30 15:07:40 EDT 2008 | jemills
Hello I have a new 0402 pad design on a recent board were building in future. On closer look i thought the pad was a thru hole mount , but upon closer inspection the round pads are for 0402 comps. I had a discussion with the engineer and he said
Electronics Forum | Fri Mar 06 10:50:21 EST 2009 | fountain42
Just my opinion but it look's like your doing a great job. i would try another paste. I'm somewhat lucky that we get to use OA's. If your stuck using the no-cleans they are so tempermental. (The nitrogen is making up for the poor paste) Your de-wetti
Electronics Forum | Fri Mar 06 10:46:35 EST 2009 | davef
First, we agree with Loco that your QFP is nonwetting, rather than dewetting. Your sceen-shots look like ol' timey SnPb paste recipes. Turn-up the heaterometer dial. Second, on nitrogen: * We kinda think your O2 needs to be around 100ppm with 99.99%
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