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Old 12-01-2014, 03:55 PM   #1351 (permalink)
e*clipse
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I really like the prototype possibilities with the heat gun, in fact I'm ordering one today. Any suggestions with those e-bay ones?

It looks pretty easy to populate a board section by section, testing your circuit along the way. Until I saw this video I though my only options were either the manual soldering (which I've been putting off . . . ) or to go full "semi production" with the toaster oven.

This is an awesome middle ground.

Paul - if you want to do even small batch stuff, I would suggest a stencil. I got a stainless stencil when I made my 1st rev BMS, and it really made the solder past job a lot easier. I just populated the board by hand after that. Regarding 64 pin chips and the like, they really do pull into place with surface tension, like the video.

- E*clipse


Quote:
Originally Posted by Astro View Post
It worked really well for me.

Not a single component failure that i can remember in over 50 cell top BMS modules and 3 master modules.

Also now i have a handy heat gun on my workbench for things like heatshrink and plastic bending.
I even used it to test the temperature sensor on each of the cell top modules.
I noticed in the video he "tidied" up the solder paste. I found that was unnecessary unless you had really piled on the paste. Even if the paste hangs off the pad a little, surface tension will bring it right back onto the pad when the paste melts.
After doing a few modules you get the hang of the paste syringe and excess like he had doesn't happen.

I was initially worried that i would over heat the components. But you quickly get to know how rapidly the heat gun melts the paste and you move on as soon as the paste melts fully.
Watching a few videos of toaster ovens and their temperature curves, they heat the components up a lot slower and cool them down a lot slower.
So the heat gun approach may cause more thermal stress as the outside of the component will heat up much more rapidly than the inside of the component.
But that may be a good thing as it is the solder paste we want to heat up not the component innards.

All i can say is it works perfectly for me.

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