Electronics Forum | Fri Apr 23 13:31:20 EDT 2004 | russ
The toes of leaded devices are problematic in fillet formation. A lot of the time they have the copper from the lead exposed so it becomes oxidized and won't readily take solder. Normally this is of no concern if the heel and side fillets are forme
Electronics Forum | Wed Jun 21 22:07:09 EDT 2000 | Jason
We are going to try double sided reflow for the first time. Can we use the same 63/37 paste on both sides? The board also has bare copper pads i'm pretty sure. will this present any challenges? The bottom side has a QFP on it. Should it stay on?
Electronics Forum | Thu Sep 16 12:06:29 EDT 1999 | Scott S. Snider
| | | Hi, | | | | | | Can someone pls suggest to me the best reflow temperature setting | | | for a force air convection oven. The details is as follow. | | | 1) Heller 1700s | | | 2) 12 zone---6 top and 6 bot | | | 3) Solder paste --- Qualitek 691
Electronics Forum | Thu Jun 22 12:25:07 EDT 2000 | Boca
Jason, What Chrys said! Don't try to run the bottom cooler, tried it in the mid 80's, don't work and don't want it to work. If one side of a fab is maintained cooler than liquidus and the other side into reflow it would have an easy 40C temp diffe
Electronics Forum | Sat Aug 13 11:14:11 EDT 2005 | Ftiscar
Does any body knows if there is a design rule on copper pads against component weight so they do not drop on secon reflow process?
Electronics Forum | Wed Apr 16 09:25:55 EDT 2008 | hussman
Do you specify copper weight on your boards? This could be the difference between the the boards. Also the finish will be different between the boards as well. These two factors are enough to cause bottom side parts to reflow and fall off. In eit
Electronics Forum | Wed Apr 06 21:37:35 EDT 2005 | KEN
Are you saying you have solder balls (as in solder paste balls) at the lead tips (or land tip)? This means your thermal profile is not hot enough. why the sudden cahnge? I will bet the lead frame material was copper and is now alloy 42. sounds like
Electronics Forum | Wed Apr 16 19:23:52 EDT 2008 | molos21
I think you are close to the problem when you expect the pcb having a problem. When I look at your different pics I saw that your via holes looks like this pcb has a hasl finish... and when i look at Q 14 this picture tells me that the pcb is not an
Electronics Forum | Wed Jul 03 10:50:06 EDT 2019 | rgduval
An 8 zone oven will give you better thermal control over the whole process. It's useful for lead-free soldering, or for boards with varying thermal loads/shadowing, etc. You can make a 5 zone work for lead free, provided the boards don't have signi
Electronics Forum | Tue Jun 28 18:20:49 EDT 2005 | russ
Matt, have you run a profile on this board? Just because it's .062" doesn't mean that any old .062" profile will work. We have .062" thick boards that almost nil for copper and other are utilizing 2 oz. layers internally. They require quite diffe
