The main reason is cost.If FR4 is $1, them polymide
is $3, PTFE is $10. Others are FR4 is easier to
process compared with polymide and PTFE,also less
moisture absorption.
   Generally speaking Tg for FR4 range from 110 C to
180 C depend on resin system.
   FR4 subject to 320 C is sure to thermal degrade.
Usually FR4 can't withstand 288C for more than 30
seconds.(Soldering temp.)

  Just some personal ideas.

  Shirley



--- Jonathan A Noquil
<[log in to unmask]> wrote:
> Hello TechNetters,
>
> Why does FR4 material is so common in PCB
> manufacturing
> and the demand is great?
> Why not poliyimide? Teflon? etc.
>
> What are FR4 advantages over those mentioned above?
>
> Was it Tg?
>
> By the way FR4 Tg is 145?
> If this is so if we subject the material in 320 Deg
> C, Is this material
> degrades?
> Any expalanation for this is highly appreciated
>
> Thanks
>
>
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