Hi Ed, We have been using vapor phase reflow since 1992. The one advantage that no one has seem to mention is that you can get 100% reflow on all components from the first PWA you assemble. We make some very expensive Single Board Computers PWA for space applications that the PWA alone can cost over $4K and has 24 layers. In a substantial amount of cases your are only building 5 or 10 of a certain type. If it has to work 100% of the time from the first PWA you profile, vapor phase is it. If you can afford to get a good sample of completely populated PWA then forced convection will work out better. I agree the fluid is expensive but once you set the profile you don't have to worry about a part change effecting your process. I think Dupont K-6 fluid boils at 221C. Hector Valladares Honeywell -SASSO Production Staff Engineer 727.539.3683 voice -----Original Message----- From: McMonagle, Mike [mailto:[log in to unmask]] Sent: Friday, March 03, 2000 2:45 PM To: [log in to unmask] Subject: Re: [TN] vapor phase reflow Ed, Thanks for the due respect, I'll take it wherever I can get it. I do not disagree with the points that you, Brian or Larry have raised, vapor phase can have great benefits in certain instances. However, it is not a process to move into without a good reason for doing so. And in the majority of applications, a modern forced convection reflow system will achieve desired results without the high costs that can be involved with vapor phase. Brian's points regarding the GWP of these materials is another negative looking towards future usage, it is just a matter of time before they become heavily regulated, taxed and ultimately outlawed ala CFCs and lead. Even 3M makes note of the high GWP of Fluorinert in their data sheets, right after they trumpet the fact that they are VOC free. Finally, the current selection of perfluorinated fluids will not exceed a temperature of 215C, ruling out use for high-temp alloy soldering. The FC-71 you mentioned was discontinued by 3M without replacement back in 1989-1990 due to lack of demand, and there is no other manufacturer I'm aware of making anything with a boil point above 215C. Mike McMonagle PCBA Process Engineering Telxon Corporation (713) 307-2443 www.telxon.com -----Original Message----- From: Edward J. Valentine [mailto:[log in to unmask]] Sent: Wednesday, March 01, 2000 2:34 PM To: [log in to unmask] Subject: Re: [TN] vapor phase reflow Jason - With all due respect to Mr. McMonagle, vapor phase reflow with preheating (an integral part of many units since the mid-80's), can produce excellent results in very dense assemblies and backplanes. The chief advantage is its very even heat distribution over the assemble. The highest temperature fluorinated liquid that I am familiar with is FC-71, which has a higher boiling temperature than the 215C (419F), FC-70. The FC-71 is 250C (495F). The liquids are very expensive, but the only fluids that were/are regulated were the secondary fluids (Freons), not the Primary fluorinated fluids since they are not a HFC or cause any effect on the ozone, nor are they a regulated contaminant,but that may vary at some locales. Generally, forced convection is the preferred reflow process, but it is not a panacea for all applications. If you would like to discuss some more, please feel free to contact me offline. Ed Valentine Electronics Manufacturing Solutions 8612 Mourning Dove Road, Raleigh, NC 27615 Phone: (919) 270-5145, Fax: (919) 847-9971 Email: [log in to unmask] Website: http://www.ems-consulting.com ----- Original Message ----- From: Jason Gregory <[log in to unmask]> To: <[log in to unmask]> Sent: Wednesday, March 01, 2000 8:53 AM Subject: [TN] vapor phase reflow > Hello techies! > > I am looking for anyone who has performed any qualifications on the advantages/disadvantages of vapor phase reflow. Particularly dealing with higher temp alloys. Is it the way to go? Is convection better? Who are the major manufacturers? Are silicon castments to keep the bottomside components from falling off mandatory? Any replies are GREATLY appreciated. > > Jason Gregory > Production Manager > Electrospec > (713)784-4900 > (713)784-1194 fax > > ############################################################## > 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 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 1.8c ############################################################## 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. 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If you need assistance - 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 1.8c ############################################################## 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 Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ##############################################################