Hi Technet

My company recently had a PWB assembled. It had about 75 SMT IC's some with
0.5mm lead pitch. The assembly house said they silk screened on flux only
and allowed what solder was on the PWB pads and the leads themselves to
effect the connection. Is this usual??

I thought that a slurry of flux and granulated solder particles was applied
to the board prior to placement and heating. They used a hot air heating
system and we had many cold solder joints especially in the PLCC sockets.
In about two weeks we're having more boards assembled. I welcome advise on
how/what to specify to the assembly house.

Thanks in advance -

Ray Klein    [log in to unmask]