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N2 reflow

mkwong

#2728

N2 reflow | 15 October, 2000

I have a question for N2 reflow, I want to know how difference of the O2 PPM in reflow oven then get the result? Now, we use the N2 to purge into BTU oven and measure the O2 PPM is about 1,000. but cannot find the difference to compare to compress air. We use the N2 cracker, the output is 900 PPM. Beside, I want to find the support document for about the N2 reflow.

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#2729

Re: N2 reflow | 16 October, 2000

MK: If you are getting good product with air, here�s what you should do: * Turn off the N2. * Sell that N2 cracker machine. * Pat yourself on the back. * Go out for beers. [Not any of that Canadian Fosters crap, tho][Did you know that Ozzies don�t even drink that stuff???? Right, Dreamster????] * Live well and live long.

Now, if that�s not the correct answer, here�s some thoughts: * Is 900 ppm your N2 purge rate? What is the duration of your purge? * Is 1000 ppm your O2 maintenance level? If so, that�s approaching "thin" * Is someone turning the N2 off? * Are your N2 curtains in place and working properly?

Think about: * Checking Marc and Earl�s comments on N2 reflow in the fine SMTnet archives. Altho, there does seem to be an echoecho inin herehere * Talking to techietypes at BTU * Searching SMT Magazine. There�s at least 20 nitrogen soldering articles on their site. * "Circuits Assembly" lists the following as Top 100 Articles: - Nitrogen Atmosphere: Who Needs It? By Dr. L. Lawton July 1998 - Reducing the Cost of Inert Soldering By M. Theriault and P. Blostein July 1998 * SMTA Journal - Inerting The Wave Soldering Process With Membrane-Generated Nitrogen, C. Shea 09/12/1999 - Solderability Of Different Board Finishes Under Nitrogen Atmospheres With Different Rols, J. Tauchmann 09/12/1999 - Solderability Of Printed Wiring Boards With Organic Solder Preservation Under Nitrogen Atmosphere, T. Zachert 08/23/1998 - Technical Advance Improves Reflow Process Reliability And Consistency, B. Bailey 04/28/1997 - Reducing Solder Defects Under Nitrogen With Varying Oxygen Concentrations, H. Hsiao 04/28/1997 - Implementation And Production Test Results Of A Closed Loop Control Of Atmospheres For Soldering, N. Saxena 09/10/1996

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