I use a Transition Automation Semi- Automatic stencil
printer with laser cut frameless stencils. My solder paste is an SN63/PB37 RMA 291. I do not operate with in a controlled humidity enviroment. The room temp generally runs around 70 deg's but humidity can vary with the swing of a New England day. My problem is the clogging of fine pitch apertures after 4 0r 5 boards, if printed one after another. If there is a time delay say 15 minutes its every board. This causes the need to break down and clean the stencil frequently. Any suggestions.