[sdiy] What the heck is this for?

[Joe Grisso]

On Wed, Oct 29, 2008 at 5:27 PM, Neil Johnson
<neil.johnson97 at ntlworld.com> wrote:
> Hi,
>
> Joe Grisso wrote:
>>
>> Those look like solder paste masks for SMT devices. You can use
>> those for single chip placement for doing SMT parts. You apply solder
>> paste to a small squeegee, place the mask over the pads on your PCB,
>> then squeegee the paste down. Once the paste is down, you place the
>> part on top of it and then heat up the solder with a hot air pencil.
>
> Most of those masks are for BGA parts - good luck soldering those with a hot
> air pencil!

Hey, if someone wants to try, I've got a gold star for those who succeed. :-)

I always use a BGA station for that. Basically, a hot-air pencil
mounted to a clamp stand with a custom tip on it, and a heater plate
underneath. If we need to inspect the joints, we send it out for x-ray
photos.

--
Joe Grisso
Detachment 3 Engineering