You're correct that's a tough job. If this phase of evaluating pastes, our test is a relative comparison of how well pastes wet. It is not a measure of how well a component pad will wet in production. In the test: * Clean (i.e., chemically or with abrasion) the tarnish from a sheet of bare copper laminate. * Print the paste on the laminate, using a stencil used in evaluating pastes. [Check with Phil Zarro for a recommendation.] * Reflow solder the laminate using the paste manufacturer's recommended profile. * Clean the laminate with isopropyl alcohol. * Inspect the solder fillet at X10 magnification. Dave Fish ----- Original Message ----- From: "Lou Hart" <[log in to unmask]> To: <[log in to unmask]> Sent: Monday, December 17, 2001 1:07 PM 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 ---------------------------------------------------------------------------------