Mounting a BGA on a PCB Quickly and Cheaply.

Well, the XuLA2 PCBs arrived last week and now they are moving through assembly. But before I could start that, I had to build up one of the boards to make sure it worked. (I wouldn't want to assemble a batch of boards at $60 a pop and then find out the PCB was wacked.)

The XuLA2 board has a 256-ball BGA on it. In the past, I've sent a single board and BGA to my assembler and had it mounted. Then I would assemble the rest of the board and test it. The problem with doing this is the delay:

Monday: I mail a PCB and BGA to the assembler. (They are forty miles away.)

Tuesday: The assembler receives the package and - if they jump right on it - mounts the BGA on the PCB.

Wednesday: The assembler mails the mounted BGA and PCB back to me.

Thursday: I receive it along with a bill for $50.

To avoid a three-day delay and $50 out-of-pocket, I wondered if I could mount the BGA myself. The total cost of the BGA and PCB was less than $35, so the potential loss was minimal if I screwed up. And I could always fall back on my assembler if I failed.

While I didn't have the temperature-controlled convection heater or the X-ray inspection machine like my assembler, I did have a $40 paint stripper that should heat the BGA enough to make it reflow. Surprisingly enough, I was able to successfully mount the BGA to the PCB using very simple tools and procedures. Here's a video that shows how I did it:

The first BGA I mounted was a failure, but every one since then has worked. I wouldn't employ this technique on a board I'd send to a customer or one with a large, expensive BGA, but I would use it for short-term prototypes with mid-size BGAs.

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Comments

Very cool. You make it look so easy :)
Tommy
 

It may actually be easy. I avoided doing this for the longest time because I figured I would never get the BGA aligned with the PCB footprint. I guess I only have to get close so when the solder on the pads melts it draws the BGA into alignment. Any way, that's my guess.

It appear very easy to do when it's you who show it ;)
Hack a Day linked your Video too :)
http://hackaday.com/2012/08/27/bga-soldering-with-a-paint-stripper-and-s...
and for "when the solder on the pads melts it draws the BGA into alignment" you are
true , it's the capillary effect.
Cheers.
Fabrice.