Soldering the E Series

I am having a hard time with oven soldering the E Series Board. We have a PCB with pads for the castellated pins on the E Series module, and we apply an even layer of solder with a stencil. However, after putting the board through the IR oven, the solder on the pads will melt, but often many pins would not bind well to E Series module. Adding additional solder to each pin helps, but even then sometimes the solder doesnt fully bind, and this is fairly time consuming.

Has anybody else encountered this issue? Aside from soldering it by hand, are there any tips or tricks I could employ so that the solder better binds?

I’ve never encountered that problem, though I haven’t assembled that may E Series boards. Are you using a polyimide stencil? You might want to try a thicker stainless steel stencil.

I’ve always used low temperature solder paste especially with the modules to make sure it fully melts and flows.

The solder should wick up into the castellated plated hole. If it’s not doing that, you may not be getting enough solder paste. I’ve never had to do it with the E Series, but there is a technique where you extend the stencil hole farther back toward the middle of the module over areas that are soldermask. It provides an additional volume of solder to make sure there’s enough. It should just wick out onto the parts that are not mask. If you look at the Eagle files for the Electron Asset Tracker V2 you can see it in the u-blox GNSS module footprint.

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