Electronics Forum | Mon Nov 12 18:08:37 EST 2007 | samir
That's when you give that "Supervisor" a tall glass of SHUT THE F*CK UP. I betcha you regret even mentioning it to him. I'd have just made up some techno-babble and switched it regardless. Told him something like - "pure IPA will act as a catlyst
Electronics Forum | Fri Nov 16 07:47:56 EST 2007 | realchunks
Stress cracks generally happen at wave solder, not reflow. But so you know, stress cracks from heat occur from the body and work towards the leads. They are generally circular. In the past, these cracks where blammed on the nozzle of the placement
Electronics Forum | Tue Nov 27 20:05:31 EST 2007 | shy
Dback, Current method is by using dispenser machine to dispense the glue at PCB. This non-wetting is randomly and not repeating to the same location. My adhesive height is 0.01" to 0.035". Is this will cause the component to had a gap between the t
Electronics Forum | Mon Dec 03 20:30:58 EST 2007 | shy
Q: I thought you said that the parts that weren't wetting in reflow were the parts with epoxy. A: Yes you're correct. Q: The question I have is do they wet in wave solder, and if they do, why does it matter what happens to them in ref
Electronics Forum | Thu Nov 29 16:00:03 EST 2007 | jmelson
Desoldering often applies a LOT more heat and thermal stress to the part, and maybe mechanical forces while everything is hot, to get the part free of the board. So, a lot of damage might be done there, making post-mortem harder. Without the leads,
Electronics Forum | Tue Dec 18 10:08:16 EST 2007 | bbarton
Drill a hole through the board (or the BGA) and set a thermocouple into the center of the device (in the X Y and Z dimensions) and run your profiler through the oven until you get the temp you need in the center of the BGA. Attach a second thermocoup
Electronics Forum | Wed Dec 19 18:41:33 EST 2007 | darby
You printer is not solely designed for printing solder paste. This is why some of the options you would never use for paste appear in the menu. You may actually be printing overlays or yes, even t-shirts. This is why you may want to flood/print, prin
Electronics Forum | Fri Jan 04 07:54:24 EST 2008 | benzy1961
My experience has been very different from the other responders. We put an in-line system in place about 3 months ago and the results have been pretty eye-opening. We were astounded to see how many prints were actually bad once we started inspectin
Electronics Forum | Fri Jan 04 09:01:35 EST 2008 | davef
Here's a link to the article that Loco references in the above post: http://www.smtnet.com/library/files/upload/DevelopingaReliable.pdf The table seems to be taking a simplistic approach. J-STD-020C, Table 4-2 lists nine catagories of MSL classific
Electronics Forum | Wed Jan 23 19:44:45 EST 2008 | hegemon
In addition to the pre-emptive steps mentioned above, in my experience there are certain BGA package designs that seem more prone to that corner bridging. I have seen some packages that will essentially "curl" down at one corner as the package begin
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