Re: BGA at home?

Did you use flux with a different melting point for the bottom part?

I suppose you are asking about the solder (the flux is the brownish
stuff which boils and evaporates while soldering, its purpose is to
solve the oxides and to prevent new to build etc.- at least in my
English).

The answer to that is no, during reflow both the top and the bottom
part soldering joints are liquid. The parts on the bottom side are
held by
surface tension, which is enough to hold resistors, caps, TSSOP
chips, SO-chips etc. I have not tried it on BGAs on the bottom,
I strongly suspect it will hold. The parts which will obviously not
be held (e.g. a metal can quarz oscillator) just get soldered by hand
later.

Dimiter

------------------------------------------------------
Dimiter Popoff Transgalactic Instruments

http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/


amerdsp wrote:
On Mar 1, 11:32 pm, Didi <d...@xxxxxxxxxxx> wrote:
CC wrote:
Hi,
I know it is possible to solder small BGA chips using a toaster oven.
Now, I would like to know if it is possible to solder a Blackfin to a
PCB at home?

If not, does professional services can do it?
Thanks

I have been doing this with 1.27mm pitched BGAs without many problems.
Here is how:
I use some flux to stick the BGA in position, then fix the PCB to
some preprepared piece of wood. I set the oven (kitchen oven,
one of the largish ones) to 220-240C and wait until it begins to
regulate; then I put the wooden plate with the board inside,
150-200mm under the upper heating element. I close the door
and set the oven thermostat to max then; I rely on the IR from the
upper (only it is on, actually) heating wire to do the heating.
Periodically I open the door and check the board themperature
using an infrared thermometer; when it reaches 220 or 240 C
I *carefully* take the wooden plate with the board out and leave it
to
cool down. Once I was not careful enough, hit the plate not so hard in
some obstacle and all the parts slid all over the board, quite a
nightmare.
Well, that's it. After that comes washing etc.

Here is one of the first boards I did like this 6-7 years ago :http://tgi-sci.com/dsv/pndcptm.gif

The bottom side parts are reflow soldered first (there are another
4 SDRAM chips and other stuff), then all reflow solderable parts
on the top side are put and reflow soldered as described above.
The through-hole parts come last, hand soldered.


Did you use flux with a different melting point for the bottom part?
.

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