Is time to reflow really dependent upon the flux type? I agree with the others - mass, geometry, and of course the alloy metallurgy. Kevin -----Original Message----- From: Inge [mailto:[log in to unmask]] Sent: Tuesday, July 28, 2009 1:29 PM To: [log in to unmask] Subject: Re: [TN] Solder Paste test method mods Graham, I can't see the purpose of such a requirement. Time to reflow is dependent on the hotplate's surface condition, the contact surface geometry, used flux and maybe more factors. I have never seen any useful investigations, nor any papers on this matter. The time to reflow on a hotplate...what is the need of that? Heat transfer varies from machine to machine, from process to process. Inge ----- Original Message ----- From: "Graham Naisbitt" <[log in to unmask]> To: <[log in to unmask]> Sent: Tuesday, July 28, 2009 5:40 PM Subject: [TN] Solder Paste test method mods > Greg and fellow Techies > > I am in the process of submitting revisions to solder paste tests called > up in TM-650 and need your help. > > In 2.4.43 Solder Ball - 2.4.45 Wetting and 2.4.46 Spread Tests, we need > to allow for lead-free alloys. In each of these there is a quoted time: > > "The reflow shall occur within 20 seconds after the specimen is placed in > contact with the hot plate." > > The recommendation is to include the following: > > "For lead-free solder pastes, the reflow time shall occur within 30 > seconds after the specimen is placed in contact with the hot plate." > > Does anyone out there in Techieland have any objections to this proposed > addition to each of these test methods? > > Thanks in advance > > Regards > > Graham Naisbitt > Managing Director > > E: [log in to unmask] > P: +44 12 5252 1500 > F: +44 12 5252 1112 > W: www.gen3systems.com > > GEN3 SYSTEMS LIMITED > Incorporating Process Support Products > Unit B2, Armstrong Mall > Southwood Business Park > FARNBOROUGH > Hampshire GU14 0NR - UK > > Engineering Reliability in Electronics > > > Registered Number: 4639449 (England & Wales). 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