Just a little history ... We had a high volume assembly that uses a DPACK package that get hot during normal operation, by design a heatsink was provided by the board using large copper pads. One beautiful day there were missing solder paste to that particular device ( not sufficient coverage ) and the amount of solder were not enough to make a good thermal contact with the board heatsink and to make things worst visually were very hard to detect insufficient solder because the big void were under the part. This particular module failed at the costumer, and then started a chain reaction from our customer CEO down to the poor manufacturers guy ( was me on that time ) Given a high volume manufacturing operation only few options could be used to solve this problem, and one of the options were to use automated solder inspection after screen printer. After that we bought a Screen printer with 2D inspection and we never had a problem like that again! This tools are not used only for process control but to avoid problems in the field, so the investment depends who are your customers and how much cost to you field failures ... Thanks Jorge Santana -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of 27782 Sent: Tuesday, December 30, 2003 12:56 PM To: [log in to unmask] Subject: Re: [TN] Paste Deposition Hi Steve, Thanks for the response. Your response was the premise behind my question and as to why I presented the question. Most folks I talked to due measure the first board and then again at some quantity or time after and as you put it is there a benefit to the investment? Lets see what we get! Thanks Dan mauro Steve Gregory writes: > Hi Tom! > > Yes, and those systems aren't that cheap either! > > Let me just throw this question out to everybody; let's assume that the > stencil has been ordered correctly (correct thickness for the type and pitch of the > components being placed), the printer has been set-up correctly (correct > squeegee speed, pressure, and separation speed, along with proper board support), > is there REALLY any value added, or will things vary THAT much when using > METAL squeegee blades, that thickness measurements need to be done every 25 boards > or whatever, during a run? > > I have my own opinion, and experiences about this...but I would like to hear > what everybody else thinks. > > -Steve Gregory- > >> Use ASC212 for solder paste thickness and volume. Currently check the first >> two boards at beginning of the run and every hour thereafter. Have >> experience with CyberOptics LSMII and Sentry- running a gage R&R will reveal a lot >> about the measuring system. Depending on the system the GR&R ranged from 5 to >> 25% . >> >> Tom Gervascio >> Senior Process Engineer >> Sparton Electronics >> (352) 540-4040 >> > > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------