19 Mar
2015
19 Mar
'15
9:52 a.m.
On Mar 19, 2015, at 12:30 PM, Jon Elson <elson at
pico-systems.com> wrote:
On 03/19/2015 09:29 AM, Paul Koning wrote:
Nice solution. Yes, that?s the main detail the article mentions: the sensor has to be in
a spot that has similar IR response as the actual board. The solution used in the article
is to use a spare (blank) board for a reference. A different board with similar ratio of
copper to etch should also work. Your solution is elegant if there?s a suitable spot you
can arrange.
paul
I used to think of BGA as not possible for home
construction. Then I read a nice article ?
https://www.beta-estore.com/download/rk/RK-10001_76.pdf ? about reflow soldering using
what amounts to a toaster-oven with a temperature control added, which apparently does the
job just fine. There are some details to get right, which the article explains.
I
reflow boards in a modified toaster oven, not too different from the one in the picture.
But, it did NOT work well when I first tried it. I just hung the thermocouple in the air,
and the boards were burnt to a crisp! The IR from the heating elements is absorbed VERY
well by the boards, and they heat much faster than the air. So, my trick is to poke a
very tiny thermocouple into a plated through-hole in the board, and then it reads the
actual temperature of the board. I still have some problems with hotter and cooler areas
of the oven, but you can usually find a good compromise.