I'd get an analysis of the solder bath contaminants. You may have some contaminant above the J-STD-006 limits that is causing excessive dross. I would not expect an organic contaminant since they tend to float and are unlikely to get pumped onto the weir. Dick Dick Krug, CSMTPE SMT Process Engineer Sparton Corporation 30167 Power Line Road Brooksville, FL 34602-8299 p (352) 540-4012 (Internal Ext. 2012) [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Cedric ORAIN Sent: Monday, January 17, 2011 2:57 PM To: [log in to unmask] Subject: [TN] Board failure due to fibber like fragments of alloy after wave soldering After wave soldering of boards with both SMD and PTH components, 18% of the boards failed during ICT. The failure is due to shorts between SMD pads. These shorts are caused by "fibber like" fragments entrapped in solder joints. We are looking for root cause of this level of waste. These fragments are very similar in aspect with dross that we found on the top of the wave "head" after the pump stop. You can see dross picture in the pictures posted here: http://ipc-technet.groupsite.com/gallery/17663 The alloy is Sn63Pb37 and the flux is an alcohol based no-clean flux. Soldering under air atmosphere. The design of the board is ok. Dross is removed daily. Did you ever encountered this kind of issue (I mean with such a rate of defect)? I'm wondering if the aspect of the dross shown in the picture is normal or is it due to a pollution (metallic pollution: high Cu rate?? / organic pollution : epoxy, fiber glass fragments ...). Thanks for your in advance for your help and support, Best regards, Cedric ORAIN -----Message d'origine----- De : TechNet [mailto:[log in to unmask]] De la part de Christopher Young Envoyé : lundi 17 janvier 2011 09:30 À : [log in to unmask] Objet : Re: [TN] POP Technology Can someone give me their experience of POP technology (Placement on Placement) OMAP and memory FPGA devices, and other pitfalls experienced. Regards Chris -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Brian Ellis Sent: 15 January 2011 14:43 To: [log in to unmask] Subject: Re: [TN] NTC Friday Element Quiz - the Answer In 78 years, 58 of them since I graduated as an electronics engineer or 68 of them since I built my first crystal set, but having worked on the chemical side of electronics assembly since 1957, I'm with you all the way, Bev. Brian On 15/01/2011 14:07, Bev Christian wrote: > Dear Mr. Hillman, > I was a little taken aback when in an earlier quiz you labeled antimony as a > metal rather than as a metalloid, but I can live with it, I guess. However, > for you to call silicon a metal is just too much! In 57 years, 41 of those > as a chemist (I am counting from when I decided to be one in grade 9), I > have NEVER before now heard anyone call silicon a metal. As a main group > chemist (fluorine chemist actually), I consider it a non-metal and am > willing to concede it is a metalloid, but metal? Never! You are poaching, > sir. I will stop short of demanding satisfaction. However, I do ask you to > respond and I also ask fellow TechNetters their opinion on this. > > Bev > RIM > > PS For those of you new to TechNet Dave IS a dear friend and this is all > pretty well tongue in cheek. And seeing this venue is overrun with > engineers, rather than scientists, I highly expect I am going to be > out-voted, shot down in flames, made into toast and other alliterations. > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman > Sent: Friday, January 14, 2011 4:03 PM > To: [log in to unmask] > Subject: [TN] NTC Friday Element Quiz - the Answer > > Hi folks - Here is the Friday Element Quiz Answer: > > The Question: > > The first "pure" use of this element began in 1823. This element is > sometimes classified as a metalloid. The density of this element increases > > when it is melted. The native oxide of this element prevents further > oxidation of the element below 900C. What element is being described? > > The Answer: > The element is Silicon (Si). Silicon is a metal that enables technology in > a multitude of ways. Silicon is a deoxidizer in steel production, the > basis for integrated circuits, glass, cement, protective coatings for high > temperature applications, and families of polymers. Ge atoms are larger > than Si atoms so an alloy of 85%Si and 15% Ge has an average interatomic > spacing slightly larger than pure Si. When a pure layer of Si is deposited > on the 85/15 alloy, the Si becomes strained resulting in a 70% faster > signal speed parallel to the surface! Less than 1% of the world's > production of Si is the pure form but that 1% (approximately 40K > tons/year) is roughly equal in total dollar value to the other 99% of the > metallic Si production. > > > > Lots of good guesses (this was one of the tougher quizzes) - the winner of > this week's quiz is Bev Christian of RIM. Clumpy have to sneak onto the > A380 in Germany and head for Canada: > > So far Clumpy has: > > Week 1 Lamar Young, SCS Coatings > - accomplished nothing (drank lots of coffee) > > Week 2 Bev Christian, RIM > - conducted REACH material testing > > Week 3 Drew Meyer, Benchmark Electronics Inc. > - Solderability testing and mowed the lawn > > Week 4 Ian Fox, Goodrich > - had an epic journey of travel > > Week 4 Gary Ferrari, Garrick Global > - unknown > > Week 5 Fredrick Miller, Astrolab > - unknown > > Week 6 David Nelson, Raytheon > - Was a tackling dummy for Dallas Cowboys > > Week 7 Graham Collins, L3 Communications > - Cleaned gutters and painted window trim > > Week 8 Bill Noel, ITT Geospatial Systems Division > - unknown > > Week 9 Steve Gregory of RD Circuits > - unknown > > Week 10 David Bealer of Watchfire Signs > - descaled the in-line wash machine! Ouch! > > Week 11 Dick Krug of Sparton Corporation > - assisted with AS9100 quality management systems requirements audit > > Week 12 Steve Creswick of Balanced Enterprise Solutions > - Acted as Steve's "go fer" due to a broken leg! > > Week 13 Gebhard Neifer, Delphi > - conducted a plasma pre treatment Taguchi DOE for a sealing process > > Week 14 Bev Christian, RIM > - ???? > > Have a good weekend. > > Dave Hillman > Rockwell Collins > [log in to unmask] > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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.aspx?Pageid=E-mail-Forums for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 > ext.2815 > ----------------------------------------------------- > > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ > > --------------------------------------------------- > Technet Mail List provided as a service by IPC using LISTSERV 15.0 > 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.aspx?Pageid=E-mail-Forums for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 > ----------------------------------------------------- > ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. 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