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.
>