Electronics Forum | Wed Jun 15 08:45:25 EDT 2011 | edmaya33
check your reflow chain. it maybe vibrating causing DPAK to fall at second reflow.
Electronics Forum | Fri Aug 10 14:43:27 EDT 2007 | judym
When running some double sided reflow boards through the Heller oven, some of the caps/ res's are falling off the bottom side of the board. I understand if the parts are too heavy they wont stay in the molten solder, but these particular parts are no
Electronics Forum | Wed Nov 21 08:45:33 EST 2007 | davef
Rob: You say, "We usually determine our run process based on the heaviest components, and propensity for falling off during the second reflow process. If there's only the one BGA on that side of the board, we'd tend to run that side first." We agree
Electronics Forum | Fri May 21 15:40:58 EDT 1999 | JohnW
| | | hello...can somebody help me regarding the POPCORN at Reflow. What is this POPCORN at reflow, what it looks like, its cause and corrective action if there is... | | | | | | your help is greatly appreciated...thanks | | | | | | omat marasigan
Electronics Forum | Tue May 07 22:25:15 EDT 2002 | L_ch
Hello, As you know for the double side assembly PCBs, we normally first place the bottom side, then place top side after reflow soldering of bottom side. are there any other considerations for the sequence of reflow soldering ( bottoms side first, to
Electronics Forum | Tue Nov 20 09:50:07 EST 2007 | rgduval
Only on the bottom side? Run that side first . We usually determine our run process based on the heaviest components, and propensity for falling off during the second reflow process. If there's only the one BGA on that side of the board, we'd tend
Electronics Forum | Fri Mar 21 20:21:41 EST 2003 | Grant
Hi, I can verify that, and we have done 2 or more reflows with prototypes, using vapor phase reflow, and because there is no oxygen, the result is good, and you cannot tell the difference between the first reflow, and the 3rd. We are getting a vap
Electronics Forum | Mon Jun 18 10:11:52 EDT 2007 | dyoungquist
Almost every board/panel we build is double sided and we use an MPM SPM screen printer with no problems. The screen printer is not the cause. We have seen heavier parts fall off the first side when going through the reflow for the second side. We
Electronics Forum | Mon Aug 13 16:07:08 EDT 2007 | dyoungquist
We run double sided surface mount boards through our Heller oven without any parts falling off the bottom side unless they are too big/heavy. The trick we use is to set the bottom side temperature in the final 3 heat zones 10C-20C lower than the top
Electronics Forum | Thu Jun 02 14:57:36 EDT 2011 | davef
We don't expect properly soldered first-side DPAKs to fall from the board during second-side reflow. The ratio of weight to solder surface area for a DPAK is 1.32 gm per in^2, which is well within the limit of 44 gm per in^2. [Search the fine SMTnet
