SparkFun Forums

[ccunningham@wpi.edu]

hi all,

I've soldered maybe 5-6 of these successfully by hand but that accounts for maybe a 50% success ratio... so I usually have to try twice I guess.. now I'm faced with the somewhat daunting task of soldering 15 for a pilot project..

I've done a fair amount of smd soldering and it usually comes out well even with some fine pitch stuff.. I'm still having trouble w these blind pads...it's impossible to tell if theres a bridge which is pretty bad obviously... I have test firmware for all the pins I use to make sure they're ok... still I don't think I should need this??

I'm wondering how these are bulk manufactured as well... I tried to quote an assembly from pcbway which is supposedly the preffered assembly company but they didn't recognize it. how does sparkfun do this??

[TS-Brandon]

The Artemis module is an in-house design and is manufactured in house also. While we, at this current time due to Covid, are not running facility tours, we are still running our production machines as fast as possible. To make the Artemis possible we use stencil pasting machines that help give us precision application of solder paste. Then our PnP machines carefully place all of the components before reflow. So when it comes to our carrier boards, it's mostly machine.

But when we rework mistakes, hey it happens, there are tricks you can try. If solder is given enough flux it only wants to 'form' on a pad a certain way. What I mean by this is in videos of SMD components snapping into place when the solder melts. You can heat up the solder and move it around very slightly and if all the pads are fluid then the module should slide back to a correct orientation. This can help if there is a tiny thread of solder making a bridge. But what we typically do is heat, lift, clean excess, replace and reflow back onto the board. Luckily, the pads are staggered in a way to help minimize bridging (as much as possible).

Mass custom production with the Artemis could be difficult for some since it is a relatively new module. However, please feel free to check out this page to see if we can help: https://sparkfun.com/services.

[YellowDog]

I've done a fair amount of smd soldering and it usually comes out well even with some fine pitch stuff.. I'm still having trouble w these blind pads...it's impossible to tell if theres a bridge which is pretty bad obviously...

FRESH, high quality solder paste is a must for a job like this.
You might also consider using a stencil to apply the paste, that will ensure just enough gets applied so that you don't get any short circuits. Also the paste needs to be fairly fresh for the flux to do it's thing, old stale paste has flux that has gone bad and it won't allow the solder to flow properly.

Fresh paste + a stencil to apply it and you should have results very very close too, or at 100% after reflow.

[ccunningham@wpi.edu]

hey all- sorry for the late reply..

I spent most of last week soldering these and I think I've pretty much mastered it actually... which is good because I've got another 20 coming monday...

anyways- yes you're right abt the paste mattering a lot.. I tried to use some sort of fancy low temp paste- but it beads up into much smaller balls that short stuff, it's not the right viscocity... there's really no substitute for lead :/

you can't really just stencil and cook it though.. this never seems to work for me because one side lifts/diconnects and the other kinda smudges and shorts everywhere...

so what you have to do is make a 'bga' sort of thing out of it. but the trick here is that you need each pad to have exactly the same amount of solder on it.. so you use the stencil, add some paste, melt it, add some more paste, melt it.. repeat 2-3 times.. this should give you really uniform balls on each pad which is great.. then all you have to do is heat the bottom of the board with a heatgun or a hotplate

in future though I have to say- I thought this'd be pretty plug and play to have assembled and it seems to be wasting a lot of my time... I'll probably just go with some standard mcu with a normal package..

[KansasBot]

SparkFun manufactures carrier boards that they stencil paste and re-flow just fine. In the SparkX phases of development of those boards they were all hand stenciled and they worked fine for me. There has to be something buggy with your setup.

[ccunningham@wpi.edu]

Hi again all,

I'm waiting on jlc still (they moved factories or something) and in the meantime I'm still trying to get a quote for assembly.. pcbway still doesen't seem to know what this board is which is fine I guess I wouldn't expect them to..

I've also emailed sparkfun under their 'value added services' page, hoping I could get these boards assembled directly with sparkfun... I haven't heard back on that though. I wouldn't mind paying more(within reason) at the moment to have these assembled in the US at sparkfun...

Anyways- I don't mean to complain here but I was under the impression that the purpose of these was for them to be easily manufactured in medium to large quantities. It would've been smarter to just make a board with the apollo3 with some 50 pin board to board /socket connector... is there any plan for something like that??

any help appreciated - Colin