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Date: | Wed, 13 Sep 1995 18:55:15 +0300 (IDT) |
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Bob,
We follow our supplier recommendations:
Overnight baking (12 hr) at 80 deg.c.
Immediately before assembly 110 to 120 deg. c for 2 hours.
Wave solder within 1 hour.
We did not have any delamination or soldering problems.
Process temp depends of course on material you specify.
Consult the material suppliers.
Ipc RF-245 para.4.6.5.1 recommends 6hrs @ 121 to 149 deg c.
good luck!
Michael Weiner
Tadiran Telecommunications
[log in to unmask]
On Mon, 11 Sep 1995, BOB HOENE wrote:
> WOULD ANYONE CARE TO ADVISE THE GUIDELINES FOR FLEXIBLE
> PRINTED WIRING PERTAINING TO PRE-BAKE BEFORE ASSEMBLY.
> DURING THIS LAST AND LONG HOT SUMMER, WE SEEM TO HAVE
> EXPERIENCED UNFAVORABLE STORAGE CONDITIONS AND OUR FLEX
> CIRCUITS ARE "BLISTERING", THAT IS, THE COVERLAY IS LETTING GO
> OF THE BASE MATERIAL DURING PROCESSING. WE BELIEVE THIS TO
> BE A MOISTURE RELATED PROBLEM. WE WAVE SOLDER AND IR
> REFLOW CIRCUITS IN OUR PROCESS. YOUR ADVICE AS TO BAKE
> TEMPERATURE, DURATION, AND SUGGESTED WORKING TIME
> ALLOWABLE BETWEEN BAKE AND ASSEMBLY WOULD BE
> APPRECIATED.
>
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