Electronics Forum | Fri Mar 23 14:43:19 EDT 2018 | dleeper
What sort of components are missing? One possibility is moisture sensitive parts outgassing during reflow. The jets of steam propel the parts off the PCBA. Another thing to look at is your convection oven fan speeds. On some ovens this is adjustabl
Electronics Forum | Sun Mar 25 08:45:00 EDT 2018 | jacobidiego
Normally some random components of size 0604 or below and may be due to a thermal mass being close like a transformer or AC electrolytic caps. We tried changing fan speed, but this will change the thermal profile and avoid the thermal mass from bein
Electronics Forum | Wed Oct 04 14:18:05 EDT 2006 | C.K. the Flip
The main cause of voids is your flux out-gassing during reflow. Try a little "knee" or slight soak in your thermal profile to dry out the volatiles a bit. Typical soak ranges from 130 deg. C to 170 deg. C for around 30-90 seconds.
Electronics Forum | Thu Jan 13 17:46:04 EST 2011 | davef
We've never seen the defect that you describe, but in wave soldering-land blowholes usually are caused by moisture in the board that out-gasses through the too thin plating of through holes. * Bandaid fix: bake the boards * Long-term fix: Obtain boar
Electronics Forum | Tue Mar 27 01:52:23 EDT 2018 | buckcho
Hello Diego, are the components missing on the first side or the second side. Like Mr. Evtimov said, you can check before the oven the pcbs's visually and see what happens after the oven. In this way you can see if it is the oven for sure. Then there
Electronics Forum | Thu Apr 01 10:49:14 EST 1999 | AF Ng
| Has anyone heard of a problem with catastrophic failure of | large value (200uF) solid tantulum capacitors that have been | exsposed to high humdity. | I suppose that with water moisture seep in the capacitor, the risk is very high that abrupt o
Electronics Forum | Thu Apr 01 14:00:17 EST 1999 | Ron Beasley
| | Has anyone heard of a problem with catastrophic failure of | | large value (200uF) solid tantulum capacitors that have been | | exsposed to high humdity. | | | I suppose that with water moisture seep in the capacitor, the risk is very high tha
Electronics Forum | Tue Jan 16 13:47:24 EST 2001 | cebukid
10% on various BGA packages. I checked the profile and we are getting "ideal" reflow conditions (~ 60 sec. T.A.L.). Ramp rates, temperature deltas before spike zone, and cooling rates are ideal too. I don't believe it's a profile, print, or paste
Electronics Forum | Mon Apr 12 08:10:17 EDT 2004 | wgaffubar
We are sometimes, not always, seeing very large voids in the solder joints of BGA's with Via in Pad. Some lots of PCB will have the voids and other lots of boards will not. I feel the via's are outgassing during reflow, due to the PCB not having been
Electronics Forum | Fri Jul 13 19:35:02 EDT 2007 | hegemon
We have had good success doing pb Free QFN work. Typically for the center pad we use ~68% coverage with 1:1 ratio on the perimeter pad. For the 68% coverage we have tried cross hatch pattern, diagonal stripes, dot series, and most successfully a clo
