February 5, 2016 Some reflow soldering machines use the machine software to determine profile settings without actually instrumenting the circuit card assembly (CCA). The solder paste manufacturer/paste part number, physical size and weight of the CCA are entered into the machine and the machine software then determines the machine settings. However, in my opinion, this method does not meet J-STD-001F paragraph 4.17 which requires, in part, "a reproducible time/temperature envelope". I know of at least one major OEM that claims that this method does not violate J-STD-001. If you do not actually instrument a production CCA, or an equivalent test CCA with multiple TC, to obtain a temperature versus time profile graph how can one assure that the requisite temperatures are being achieved at the actual solder joints for complex parts such as BGA and BTC and that the TAL, ramp rates and coverage for both high and low mass components is achieved. Using multiple TC also provides an indication of whether there is even heat distribution across the surface of the CCA since the graphs for each different TC will all normally fit within the same basic envelope and if they do not there may be some type of problem. I would like folks opinion on whether J-STD-001, 4.17 mandates an actual time versus temperature graph or not. On Fri, Feb 5, 2016 at 5:22 AM, Nigel Burtt <[log in to unmask]> wrote: > There are modelling software packages based on a 3D thermal profile of the > PCB which gets you close to the profile you will need and then just needs > some fine tuning once you have a PCB to play with. > > eg http://support.fluke.com/find_it.asp?SRC=DPQ&Document=9290428 > ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________