Fellow Designers,

 

Long time lurker, first time poster.  I've had a few posts over the
years, just not very many.

 

Ok here goes.

 

What is a good overall thickness tolerance to put on your dwg for a
0.125" thick board?  This board is impedance controlled and should stay
pretty close to the 0.125" to meet our required impedance values.

 

I am kind of in a unique situation where we deal directly with an
assembly house and that assembly house farms out the board fab to
whoever gives them the best quote.  So I never know which board house
will get the board.  Hence I never know the capabilities of the board
house where the board gets sent to be made.

 

With that being said, XYZ board house wants to loosen up the tolerance
to +/- 0.012" on the overall board thickness.  This would throw our
impedance calculations off.

 

Just kind of curious what everyone would expect as a good tolerance on a
0.125" board.

 

 

John Babcock, C.I.D.
PCB Designer III



 


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