Dear Technet,

I am having big interpretation problem on the FAB drawing:-

Customer's Requirement :-

__________
|        |      preprag 0.6 mm
----------
__________
|        |      C.L.L 0.4mm
----------
__________
|        |      preprag 0.6 mm
----------

It stated on the drawing as:
a.      Thickness of copper foil is 35u 
b.      Thickness of PCB thickness is 1.5/1.6 mm



We end up getting an overall thickness of 1.7 to 1.77mm from our PCB supplier.

The PCB supplier come back with their side of the story, 
Supplier's interpretation is

----------                    -----   
|       |       35 u            ^
---------                       |      
                                |
|-------|                       |
|       |       70 u            |       
|-------|                       |
|       |                     overall thickness = 1.81 mm  
|       |                       |
|-------|                       |
|       |       70 u            |
|-------|                       |
                                |
---------                       |
|       |       35 u            v
---------                     -----
 

I would like to know whether the PCB supplier is right ?, and whar is the
correct way
to interpret the drawing.

and also does anyone know of any spec/book that tell one how to interpret a FAB
drawing ..

I'm appreaciate for any comment given .. Thanks.