Thanks very much Sean, I've updated the program. 

---
James.
 
 

> -----Original Message-----
> From: piclist-bounces@mit.edu 
> [mailto:piclist-bounces@mit.edu] On Behalf Of Sean Breheny
> Sent: 2007 Jun 22, Fri 14:50
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] converting PCB copper thickness specs
> 
> Hi James,
> 
> volume density=area density/thickness
> 
> therefore:
> 
> thickness=area density/volume density
> area density=volume density*thickness
> 
> Using Josef's numbers, we have:
> 
> thickness (in feet)=area density (oz/ft2)/8910 (oz/ft3)
> 
> For 1 oz/ft2, this gives 1.12e-4 feet or 1.34 thousandths of 
> an inch (just about what I had).
> 
> To put the formula itself into thousandths, multiply by 12000:
> 
> thickness (mils)=1.35*area density (oz/ft2)
> 
> The reverse formula would then be:
> 
> area density (oz/ft2)=thickness(mils)/1.35
> 
> Sean
> 
> 
> On 6/22/07, James Newton, Host <jamesnewton@piclist.com> wrote:
> > > >How does one convert oz/ft2 into mils as it relates to the
> > > thickness of
> > > >copper on a PCB?
> > >
> > > It should be converted thru copper density, which is 8 920 
> > > kilogram/cubic meter = 8 910 oz/ft3.
> >
> > Errr.. Huh? Yes I really am that dumb when it comes to this 
> sort of thing.
> >
> > Let me try again:
> >
> > If I have copper thickness in mills, what mathematical 
> formula yields 
> > oz/ft2?
> >
> > If I have copper thickness in oz/ft2, what mathematical 
> formula yields 
> > mills?
> >
> > > >to add that feature for the other unit selectable fields,
> > > one of which
> > > >is
> > > >oz/ft2 or mils for copper thickness.
> > >
> > > Yet another way is thickness in micrometers.
> >
> > K. Give me a set of formula and I'll add another option.
> >
> >
> > Thanks for trying to help.
> >
> > ---
> > James.
> >
> >
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