Hi Lou! One test we have successfully used on past solder paste qualifications is a long duration solder paste tack test. The process is pretty simple. We selected a test assembly which had a wide range of component types (both area array and SMT) and printed solder paste on 10 of them. We immediately populated 2 boards but the other boards we populated at 2 hour intervals. After population we insert a test assembly vertically in a fixture which provided a "calibrated" hit on the bottom of the assembly in an effort to see which components and how many fell off the test assembly. It is a very informative method for comparing the tack strength of different solder pastes over a 10 hour period and also interesting on which types of components were more sensitive to solder paste tack properties. This tack method gave us a good comparative index of candidate solder paste tack and other properties such as bridging, slump, etc. (we inspected the test assemblies before putting them in the tack "tester"). Good Luck. Dave Hillman Rockwell Collins [log in to unmask] Lou Hart <[log in to unmask]>@ipc.org> on 12/17/2001 03:07:50 PM Please respond to "TechNet E-Mail Forum." <[log in to unmask]> Sent by: TechNet <[log in to unmask]> To: [log in to unmask] cc: Subject: [TN] Solder paste evaluation TechNetters, our production people want to investigate an alternative to the solder paste we are now using. My proposal was to perform a designed experiment to see if the candidate paste is better than, worse than, or equivalent to the present paste. Factors to consider in an experiment could, in my opinion, include the pastes themselves, solderability preservative, lead finish, stencil life, etc. A big question than comes to my mind is: what measurement do we use for soldering performance? Is there a variable measurement? I'd rather not use an attribute measurement, since that, as you know, requires a relatively large sample size. I don't like the prospect of using any subjective measurement, fearing gage uncertainty will be excessive. Any comments would be most welcome. Contact me off-line for discussions if this topic is too narrow for the forum. Thanks to all. Lou Hart --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------