I am looking for information regarding the way various designers specify 
copper thickness for boards, and how this information is translated by the 
manufacturers. IPC-D-325A and IPC-D-275 are not clear on how this information 
is to be stated or translated.

We have always indicated the copper weight as the starting weight, ie. 2oz, 
1oz, 1/2oz, etc.. Some manufacturers translate this designation as finished 
weight. They will start with a lighter copper and plate up to a finished 
dimension, (start with 1oz, plate up to 2oz).

Tolerances are not stated in the IPC documents. IPC-RB-276 indicates that, in 
the case of 2oz copper, the finished surface thickness should be .003".

What is the general direction of the industry? As indicated above, I have had 
manufacturers indicate both ways.

Rich Ackerson
Sr. Industrial Engineer
Elsag Bailey Electronics
Voice 216-585-7646
Fax   216-585-8867
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