Electronics Forum | Tue May 29 15:10:30 EDT 2007 | realchunks
Hi Jerry, Sounds like the white stuff is flux. I doubt if 4 pcb mfgers could be undercuring all at once. Good point though. Since you changed washers and now have the problem - it's your new washer. Can you bring back the old one to make sure?
Electronics Forum | Fri Jun 08 17:22:51 EDT 2007 | naynayno
We have been producing an IMS assembly with SMT dpak's for some time. However, we recently encountered a new problem by chance - the parts can be flicked off with a finger nail. I state by chance because the solder joints are wetted and shiny with
Electronics Forum | Tue Jun 12 22:03:21 EDT 2007 | davef
The presence of agitation at an air / solution interface and a foaming agent causes foaming. Most water soluable fluxes contain surficants. Surficants are foaming agents. First, it's likely this foaming is caused by poor control of the temperature o
Electronics Forum | Thu Jun 14 16:52:08 EDT 2007 | joeherz
Brian, We've see foaming issues with our wave flux occasionally when running large slugs of product through the wash. We love the wave flux and changing it was not an option. Our process parameters for the wash machine we're derived via a validati
Electronics Forum | Mon Jun 18 11:54:35 EDT 2007 | grantp
Hi, The problem seemed to be across multiple batches of boards, so I think they were made correctly, and we don't use a carrier in the reflow oven. However we just moved our equipment to the new factory yesterday, and connect and start turning on
Electronics Forum | Wed Jun 27 11:59:55 EDT 2007 | samir
*Preheat zone *Maximum slope is a time/temperature relationship that measures how fast the temperature on the printed circuit board changes. The ramp�up rate is usually somewhere between 1.0 �C and 3.0 �C per second, often falling between 2.0 �C and
Electronics Forum | Fri Jun 29 09:51:27 EDT 2007 | bjrap3
I have never had a problem with any other BGA's that I reworked. I recently found out that the BGA that we are trying to rework is made poorly and warps automatically from the heat. There is nothing that we could do to prevent this. Also the board
Electronics Forum | Wed Jul 11 14:27:56 EDT 2007 | fredericksr
1) Swapped it out a few weeks ago to attempt to combat the problem ... Great minds eh? 2) I'll try changing the position setting to see if my yields improve. 3) Ahh yes, in fact, I have verified that our vacuum levels are low (range ~130). The
Electronics Forum | Thu Jul 05 10:11:19 EDT 2007 | ck_the_flip
The variables to study: * Dwell Time * Contact Length * Conveyor Speed * Parallelism * Top-side Substrate Temperature Before wave * Solder Pot temperature All of these variables are inter-related (ie changing one variable will affect another)
Electronics Forum | Mon Jul 16 12:03:42 EDT 2007 | davef
We're aware of no industy acceptance standard for max moisture content of a board. For more on moisture levels, get a copy of: "Removing Moisture from Electronic Components and Assemblies", CS Leech, Jr, Circuits Assembly, May 1994. The article disc
