Electronics Forum | Tue Apr 10 04:16:20 EDT 2012 | grahamcooper22
you are seeing a typical issue that is caused when such small volumes of paste are printed....there are several reasons for it..the tiny amount of flux in the small deposit becomes exhausted much quicker then it does in a larger deposit ( the flux ma
Electronics Forum | Mon Apr 14 16:21:58 EDT 2008 | ck_the_flip
Bottom-side SMT parts CAN and DO go liquidus during the 2nd reflow cycle. It could be that there was enough variability between the 2 different lot code PCBs to cause the parts to fall off. Remember wetting force determines surface tension (the abi
Electronics Forum | Fri Sep 28 09:30:07 EDT 2001 | kmorris
Just had a similar phenomenon 2 days ago. May relate to your issue --- or not. Like you, I did a once over looking for mechanical obstruction & couldn't find any. Ran a thermal profile on the offending PCB & all checked out. Looked in end of oven
Electronics Forum | Fri Sep 08 09:16:37 EDT 2006 | james
We are incurring problems with Film Chip Capacitors with reflow issues. Some of the parts are misaligning or not soldering on one end (almost tombstoning) . We left the parts in the dry cabinet till they were used. We tried both reflow ovens (hell
Electronics Forum | Tue Aug 17 03:26:57 EDT 2004 | soease
Well, regarding the paste specifications, it's no problem to add yours if it's not allready defined in the default library; parameters are for example, soak temp min & max, liquidous, ramp positive max, spike ramp min & max, all timings and so on. n
Electronics Forum | Wed Apr 16 11:29:31 EDT 2008 | mmjm_1099
Per Tony SMT Here are more photos: Q15, Q16, Q17 represent good transistors on a 1 up board with the transistor locations that are in question. Q13 is a good transistor on a bad 2up board. Right next to it is Q14 a bad transistor on a bad 2 up boa
Electronics Forum | Wed Apr 06 12:36:53 EDT 2005 | smt_rookie
I've tried a different lot of the same double header connector (yes its double level right angled header conector) twice but nothing has improved. I've also suspected that top row of the connector has greater heat sinking capacity (which should hold
Electronics Forum | Mon Apr 14 13:24:32 EDT 2008 | mmjm_1099
We had an order using a 2up PCB (same manufacturer) with same components and same board layout without any problems. Perfect run. The next order ran on the same day with same paste using same parts, same layout, same profile, but different 2up PCB h
Electronics Forum | Wed Nov 01 13:44:50 EST 2000 | Thomas Ballhausen
Using convection type reflow we observed following problem: One ball of a 313-PBGA appears to be dewetting. This happens randomly, i.e. no specific ball location, failure rate is rather low (3-4%), but since there are 12 PBGAs on one board the failu
Electronics Forum | Tue Feb 11 13:41:54 EST 2003 | Stephen
How are you doing things now? I'm trying to picture a place going from no reflow oven to a reflow oven without also getting a screen printer at the same time. Are you now handsoldering parts on? With these batchs you plan on doing are you going to
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