Steve: I was in the same ballpark except that my part is somewhat smaller. I can give you more details if you call me, if needed.. A quick summary of events ........ We're using an Actel CQ-132, 132 lead, 25mil pitch. Using this here 'Net I got a great lead for a suggested land pattern from Bob Vanech over at Northrup. Got our design folks to agree to the suggested land pattern. Sent land pattern to Fancort, who made me a die for forming this part in a pneumatic press (12K) (Die 9K, press 3K) The part is programmed with the tie bars on. When we get the part on the floor, we have to remove the corner metal section that joins the tie bars. Part is formed in the Fancort press and then transferred to a special matrix tray that holds the part body without any pressure on the leads. We then use a standard solder pot, and with a little practice and steady operator hands (not mine !) We lightly (I mean lightly) brush RMA flux on the feet along one side of the QFP while holding the part with a high quality vacuum pencil. We then dip the leads into the solder pot. The dip barely touches the top of the molten solder with a quick withdrawl. With a little practice, no bridges, comes out quite nice. Remember, only try to tin the "feet" Lots of articles in past periodicals and there is a "how to"document from EMPF called "manual tinning of fine-pitch" By the way, we have also done an analysis that shows that by leaving the gold on the part will not affect the solder joint due to the insignificant amount of gold remaining on the "feet" of the QFP. (Foot size ~ 50 mils by 12 mils wide.) But we're going to tin the parts anyway our whole program will use about 50 parts over a years time. I was lucky. I have only one part to deal with . Bill Kasprzak Moog Inc. 716-652-2000 ext 2507 ---------- From: Stephen R. Gregory To: [log in to unmask] Subject: [TN] Pre-Tinning Fine Pitch... Date: Tuesday, September 28, 1999 7:34PM Hi ya'll! Boy, I may have quite a task ahead of me. There's this assembly that has hit the floor that has just about every part (CQFP's and ceramic SOIC's) in the un-formed state, and we've got to form and trim, then Pre-tin the gold plated stuff. I've already got a call into Six Sigma to get a quote on doing this stuff for me, but it may turn-out that we won't have the time to deal with this build and sub-contracting the forming and trimming, and pre-tinning out (what's new?). But in case I have to pre-tin the CQFP's myself, are there any tips that anyone can share to help me get through this as painlessly as possible? These parts are 320-pin 25-mil pitch and still have the tie-bars attached. I've got a bottle of nitrogen and plan to "Rube-Goldberg" me an enclosure to blanket the pot with nitrogen over the tinning pot that I'll be using...I think that'll help to cut down on the bridging I'll see. I'm going to use an RMA flux as well...any other suggestions? PLEASE? Thanks! -Steve Gregory- ############################################################## TechNet Mail List 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://www.ipc.org/html/forum.htm) for additional information. If you need assistance - contact Gayatri Sardeshpande at [log in to unmask] or 847-509-9700 ext.5365 ##############################################################