The actual requirements vary with paste, aperture, pad, component, reflow profile...... Try this experiment: Modify screen printer (or use oversize stencils) so that you get 20% and evaluate the yield Repeat this at 40% and evaluate the yield. Do a life cycle test on the solder joints and see if anything changes. The data should indicate whether these parameters are accepable. ------------- Original Text From: C=US/A=INTERNET/DDA=ID/geezer(a)tc.fluke.com, on 5/11/98 3:39 PM: TechNet, I am currently inspecting solder paste deposits using a 3D inspection system. I am in the process of setting control limits for the boards, but I have had conflicting inputs. I have recently heard that deposits should be 20% of target for warning limits and 40% of target for failure limits. Should the target be the size of the aperture or should it be less? Is there an industry standard on paste deposit parameters? Thanks for any input you can provide. Sincerely, Brian Geijsbeek ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################ ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ################################################################