> On Apr 2, 2017, at 12:51 AM, Jon Elson via cctalk <cctalk@classiccmp.org> > wrote: > > On 04/01/2017 11:27 PM, Chuck Guzis via cctalk wrote: >> What do you do about boards with SMT components on *both* sides? I can't see >> how it would work with a toaster oven. > OK, this is going to be long. > > I do small-scale production of mostly motion control boards, but also some > nuclear instrumentation. Mostly 0603 to 0805 passives and SOIC up to 0.5mm > pitch QFP chips. I use a lot of FPGAs in 144 pin packages. > ... > > One of the tricks I found out very fast was the thermocouple doesn't absorb > IR the way a board does, the first board I did came out warped like a potato > chip and nearly black. It occurred the me to poke the thermocouple junction > into a through-hole in the board, and then it all worked. I still have some > slight problems with some areas of the oven running a bit cooler or hotter, > so I have to tweak the peak temp setting sometimes to get all the boards > soldered.
I have a nice article about toaster oven SMD work. It's in German, via the PCB Pool website if I remember right. It mentions that problem. The solution picked in that article was to use a spare board (same or similar layout) as the thermocouple holder. But attaching to the actual board sounds good. paul