hi We start to make a product which have a 0.4 mm pitch IC and start having problems with not enough solder printed, to solve this problem we had to increase the manual cleaning, now we are cleaning the stencil every 8 printings, before we was running models with 0.5 mm pitch IC's without any problem (cleaning stencil every 15 pcb's) Do you have any recommendation about solvent to clean the stencil, right now we are cleaning with regular alcohol ? We want to reduce the printing defects and reduce the manual stencil cleaning frequency.
On understencil cleaning: * It's a good idea to do this to reduce printing defects, as you say. * We clean dry. * Our cleaning frequency varies acording to product, maybe ranging from 10 to 20 prints, averaging around 12 to 15. * As long as cleaning takes less time than the slowest process in your line, probably placement, what's the worry about the stencil cleaning cycle? * Some printer equipment suppliers make retrofitable understencil autowipers for some of their equipment. * Use the solvent recommended by your paste supplier.