From my days in the Silicon Valley in California, the biggest thing I
remember about PCB costs weren't related directly to the size or
thickness, they were quantity....

I've had quite a number of double sided PCBs fabricated, along with
numerous multilayer ones, and the overriding issue with cost was the
"non-recurring costs " of generation of the masks, tooling and setup
needed to convert the supplied circuit trace films to finished boards.
Once the fixed costs are covered, the individual costs of each board
weren't usually all that high, if you had enough volume. As a simple
example, a small jumper board of about 2.5" square, double sided 60 mil
thick and only about 75 holes, with soldermask cost about a buck each at a
quantity of 200. At a quantity of 500, the price was something like sixty
cents each... Of course, this was the sort of thing that a hundred pieces
would be a near lifetime supply, and at a quantity 100, the price was
about 1.75 each.... Such is the problem of amortizing the fixed and setup
costs over a relatively small quantity.

So, any price that you get quoted on a per square inch basis will have to
carry some serious disclaimers or additional explanation of the fixed and
setup costs incurred in making the first board, along with price breaks
for quantity....

The best thing to do is to contact some places that do engineering
prototype quantity work, and see what they say. You can usually get a
decent price quote by providing the outside dimensions, basic construction
(thickness, number of layers and copper weight (thickness) along with
things like number of holes, how many different sizes of holes involved,
whether they are plated through, and whether you want a bare board, solder
plating on the exposed copper and such things as solder mask and legend
(the exact term for legend, the lettering on one or more sides of the
board doesn't come to me at this moment,)) and, of course, the quantity of
the run you want made. Of course, tolerance is also important.... If you
need ultra-precise registration between layers, that will tend to cost
more than an alternate board with a looser tolerance...

It seems like a lot of information, but once you get used to it, it's not
so bad.

Of course, if the relative amount of circuitry on opposite sides of the
board isn't somewhat equal, (called copper-balancing) the board may have a
tendency to warp during manufacture, or even warp or curl with changes in
temperature, particularly if one side uses a thick (heavy) copper and the
other lighter weight copper. This is especially important if you intend
to wave solder the PCB during assembly or other manufacturing
processes....

Of course, yet another variable in the cost issue is where the PCB
manufacturer is and what sort of volume they deal with. If you're looking
for quick turn shops, there are (or at least used to be) a lot of them
around the Silicon Valley area. However, if you're expecting to find
someone in Podunk WA, KS, OH, FL or similar locations away from high-tech
development, you may be looking at higher prices unless they are "hungry".

Good Luck
-_Rick AH7H

basketball_jones wrote:

Hello,

I am working on a PCB-based antenna, with copper on both sides.
Believe it or not, the hardest part is figuring out how much the PCB
material would cost. Does anyone have any PCB costing numbers for
FR4, FR408, Nelco 40013, Rogers 4003, any other material? I
understand that thickness plays a major part in the cost so if
possible please include the board thickness with the cost number (I am
currently thinking of using 20mils thick PCB). It would probably be
easiest if the cost was in units of US$ per sq. inch or sq. cm. Many
thanks.