Electronics Forum | Tue May 23 10:40:25 EDT 2006 | Chunks
Chris is right. You can do a good visual after placement if you have outline marks on your silk screen. That helps a lot. What size BGAs are you talking about. That would determine how critical you want to get with inspection.
Electronics Forum | Mon Jun 19 21:35:35 EDT 2006 | davef
Ahne [?] You say, "There are almost as many ways to be successful with this as there are ways to do it wrong." What do you believe are the successful and wrong was to go about cleaning stencils after the run is finished (or temporarily interrupted)
Electronics Forum | Wed Aug 16 13:31:30 EDT 2006 | a_laser
You can stop cleaning after a job when there is no more paste in the apertures. Under wiping should be done with a quality cloth and should leave no paste on the underside of the stencil (assures good contact on the next print and reduces chances of
Electronics Forum | Tue Jun 20 06:47:53 EDT 2006 | Julien VITTU (STMicro)
hung copper balance is really critical in your case. in the same configuration we have specified less than 5% copper variation between top and bottom layer if you keep this rule, assembly will be ok, otherwise you will get a terrible warpage after
Electronics Forum | Mon Jun 19 14:04:39 EDT 2006 | slthomas
Because some lead free solders are very corrosive to anything but titanium. Also "clean it very well" is kind of a crap shoot, isn't it? Did you get your solder tested for impurities and lead %age after you did the swap?