EEVblog® Electronics Community Forum
Electronics => Manufacturing & Assembly => Topic started by: gsmecher on October 02, 2020, 04:30:39 pm
-
I've been trying to reflow FMC connectors (Samtec ASP-134488-01) with mixed success on a skillet.
These connectors have a solder charge (https://www.youtube.com/watch?v=GOfiywh10UQ (https://www.youtube.com/watch?v=GOfiywh10UQ)), a little like a BGA: they come with pre-formed solder caps on the terminals, but rely on the flux in your solder paste to wet them during reflow.
These connectors are thorny for a few reasons:
- They're nearly un-inspectable and totally un-reworkable, since they're underneath the connector body
- There are 160 pins per (LPC) connector, and "most" of them need to work
- They're physically large, so any bowing or twisting of the underlying board will ruin my work
I've played with the soldering profile ("twiddling the dial on the skillet while holding a stopwatch") and dabbing flux on the part before putting it on the prepared board. I am still not getting reliable results. I am going to look at the PCB footprint today to see if it's a problem with pad sizes.
Before I throw up my hands and have the part reflowed elsewhere, I figured I'd ask here for suggestions. Please?
Moreover, should I expect the bargain assembly houses (pcbway) I'm considering to do a 100% reliable job on connectors like this? Or, am I trading my own dubious reflow for someone better-but-still-not-good-enough?
-
My thoughts, but keep in mind I have not ever tried this solder charge technique:
This process will most likely need a very controlled, repeatable, precisely timed reflow profile. If you are using a hot plate/skillet method, I doubt you will have reliable success.
The solder paste application likely has to be perfect, with the proper solder paste. What you have for solder paste may just not play well with this process. I'm sure solder paste consistency also needs to be perfect.
I would expect a shop even like PCBWay would have reasonable success, as they use proper reflow ovens, though I think there may be issues if this process is not compatible with their established profiles. They won't be modifying their oven profiles just for you...
IMHO, if this were my project, I would look long and hard for an easier solution that is more conventional. You will have higher success rate with your own work AND discount assembly companies.
-
Your guidance here (work towards a more controlled conventional reflow, rather than heading off into the weeds) makes sense to me. I have a few obvious gaps to plug before I run out of un-creative ideas.
Thanks.
-
The results from a Controleo converted toaster oven are honestly great. I have reflowed hundreds of PCBs perfectly every time with one. Total investment is about $350, and a reflow takes about 20 minutes from start to cool-down enough to remove with bare hands with leaded solder.