Electronics Forum | Thu Feb 24 00:37:08 EST 2022 | joshsvoboda
I have a pcb with an ENIG finish that is using a 144 pin LQFP and being soldered withSN100C/NC258 T4 paste. I used a oven profiler where the probes are taped down to the joint and the profiling software adjusts the program for the best profile for
Electronics Forum | Thu Feb 24 15:36:34 EST 2022 | dontfeedphils
Looks like a decent profile. Only recommendation I have would be to possibly try and high-temp solder the thermocouples rather than the aluminum tape/kapton, only because you can get air-gaps and inaccurate readings using the tape method on assemble
Electronics Forum | Thu Feb 24 20:13:22 EST 2022 | dwl
They don't look that bad, especially for SN100. There is evidence of wetting on the toe and the paste on the pad seems to have reflowed properly. What does the heal look like? That's the more critical part of the solder joint for Gull leaded parts.
Electronics Forum | Thu Feb 24 20:39:05 EST 2022 | joshsvoboda
there is evidence of wetting on the heel. This is the first time I have had this type of joint using SC100C on a leaded part. Usually there is at least some wetting on the sides instead of just looking like it is pressed in and sitting on top of the
Electronics Forum | Tue Feb 10 15:13:06 EST 2004 | patthemack
Hey Vinny, Sorry I haven't looked at this for a while. 3 things to try: Tombstoning- The ground plane side is larger because the solder mask allows for a little slop at the board shop (clearance around a pad of a few mils). Since there is not a defi
Electronics Forum | Fri Jun 16 10:38:33 EDT 2000 | Iain
I have 15 very large backplanes (.156" thick Au plating) that the ground pins of a high density thru-hole connector were not thermal relieved in the artwork. As a result we are unable to solder the 8 pins that connect to the ground plane. We know t
Electronics Forum | Wed Jul 22 13:50:49 EDT 1998 | Justin Medernach
| My firm has just begun it's first PCB that will use BGA packaging. I have been reading up on the processes involved with BGAs and was wondering if you need to apply solder paste to the pads prior to applying heat and mounting the part to the board
Electronics Forum | Mon Jan 26 04:13:48 EST 2004 | patthemack
First of all, did you profile this board with a mole, such as a KIC? Is the solder flowing, or just not wetting to the part or pad? I work with RF boards as well, but the main problem is tombstoning due to the ground plane side being larger because o
Electronics Forum | Mon Jan 26 21:10:36 EST 2004 | Vinny
I have done acurate profiling which meets the solder paste specifications. The point I am trying to highlight here is also due to the ground plane side being much larger causing the tombstone defect. I have even tried doing a linear profile, it hel
Electronics Forum | Thu Jan 29 06:58:40 EST 2004 | davef
Ramp / Soak: Tombstoning is occuring during reflow. You need to get more heat into the ground plane. Obviously a ramp aint gettin' it done. Further, without intending to disrespect your internal discussion, if a linear profile improved the situati
