Hi Werner,

I am sure you are aware that what you say is correct, but, not quite, it is
weight per square ft. This implies a thickness of copper. If you have one
ounce of copper then one would say I have one ounce. Since it is not sold by
weight it is sold by weight per surface area we can imply thickness.  The
problem is that the thickness varies because they requirement is weight per
surface area and the thickness can vary across the surface and not violate
the specification. Also the copper has as variable density due to organic
inclusions etc. The copper and laminate companies sell copper by ounces/ft2
but we measure the thickness.  One oz. copper is .0012 to .0014 thick.  This
is an industry standard and a convention.  It is not scientifically correct
but it is how the industry relates to the copper thickness vs.
weight/surface area issue.

PR


-----Original Message-----
From: Werner Engelmaier [mailto:[log in to unmask]]
Sent: Thursday, June 05, 2003 2:11 AM
To: [log in to unmask]
Subject: Re: [TN] (2) Micro-inch to copper weight conversion..Error
Alert


Hi Paul,
All of this is nice, but.......oz./ft2 is NOT a thickness--it is a weight.
It
does not convert to a fixed thickness value in any of the units you list.

Sorry,
Werner Engelmaier

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