What type of FR4 do you use?

[Ray from NJ]

Do you give just a general callout for FR4 base material
on your drawings or do you identify which IPC-4101 slash
specification to use?

I have been using the IPC-4101 /21, /24, and /26 spec on my board designs and I am wondering if it is overkill for office based electronics.

We don't do any thermal analysis and it is a real guessing game
in the initial design until the board is fabricated and we can get a probe on it.

I haven't seen any z-axis failures, barrel cracking etc. and was wondering if I could save some production costs by going to a lower grade or general specification?

Will I still maintain a 94V-0 rating?

Will my impedance modeling become unstable?

[Tom]

Ray,

The FR4 that you refer to has a high Tg rating and could be possible overkill if you are not using High Speed CPU processors that create temperatures in the 150 - 170 degree range.

I would definitely confirm the temperature ratings of the the components that you are using with your engineer (or the component data sheets) and also talk to the PCB manufacturer and ask what materials they stock for "General PCB FR4".

You might be shocked to find out that some manufacturers use the cheapest low grade FR4 material they can purchase. And they get away with it because many PCB designs are the "run of the mill" (nothing too fancy) technology.

You do not need Rogers, Getek or Nelcor materials unless your using fast CPU's or Power Supply technology.

[robert Tarzwell]

There are only so many FR4 types made and there all an overkill for genral office type equipment, the cost diffrence between multifuntional ( higher T/G) and di funtional is very little, I would suggest you contact your board shop and get them to quote you with difuntional FR4 T/G 160. There are no diffrences in quality, all FR4 made today is millitary and ipc approved. except some made in the far east. Its only a funtion of max operating temp. Which I would fiqure you would not exceed. 130 degrees C
I would also ask the board shop whos material they use do you know what FR4 you are getting?
Robert tarzwell