Geoff's method is possibly superior (more accurate in some cases) to the
one I suggested but it is a bit more work to do
in my experience the SMD pad count does not need to be exact, it is
usually a way of estimating either a test fixture or the nature
(complexity) of a board for quotation purposes
the same would be true for a stencil, a few apertures one way or the
other will not affect the price, just like 500 holes or 600 holes
doesn't, the setup overhead and business relationship are a bigger
factor
of course 500 or 2000 holes would make some difference (but there's
probably still more time in the plating tanks than on the drill either
way)
I would opt for offloading as much of this particular type of detail as
possible to the fabricator
I have stopped using periods at the end of sentences in my emails and
sometimes Capitals at the beginning as they take more time and help to
preserve the environment from wasted periods and Shift keys, hope it
does not offend
Dennis Saputelli
Geoff Harland wrote:
>
> > >I try to find out how many SMD-pad I have in my design.
> > [snip]
> > >I need the Paste Mask cout for an offer for an Laser Stencil
> > >(www.schablone.de).
> > >
> > >Edi
> >
> > Some PCB manufacturers ask for the smt pad count for
> > their quotes. To accommodate them, I do the following:
> >
> > First, do a Reports/Board Information. Now the tricky part,
> > subtract the number of vias from the Pad/Via Hole count.
> > This will give you the number of pads with holes. Then
> > subtract this number from the number of pads. What is left
> > over should be the number of pads without holes (i.e. smt pads).
> > I've verified that this works by manually counting smt pads. Although
> > I haven't actually done this exercise since P98.
> >
> > Jeff Stout
>
> Bear in mind that there *might* be pads on layers *other* than the Top
> copper, Bottom copper, and MultiLayer layers. Additionally, some of the pads
> on the outside copper layers might be masked on the Paste Mask layers (with
> fiducial pads being one such typical example).
>
> So I would suggest that you generate Gerber files from the Top Paste Mask
> and Bottom Paste Mask layers, then *import* these into a blank/new PCB file.
> After so importing these, do a Reports/Board Information to get a pad count.
> (If you want a count of the number of pads on *each* side, do a
> Reports/Board Information, *before* importing the *second* such file, to get
> a pad count for the *first* file imported. Note/save that number, then
> subtract it from the number reported after importing the second file, in
> order to get a pad count for the second file.)
>
> (This previously blank/new PCB file can then be discarded, unless you have
> some other reason for retaining this.)
>
> I was going to suggest using the "Edit/Export to Spread" command (to acquire
> details of all pads within the PCB file), but that would incorrectly count
> pads on the copper layers which were masked on the Paste Mask layers. OTOH,
> the above approach correctly caters for such masked pads (as they are not
> incorporated in the Gerber files, so will not be counted), along with any
> pads which might have been specifically placed on the Paste Mask layers (as
> opposed to being placed on the outside copper layers).
>
> How much user interest would there be in having a Process provided which
> counts the number of pads on each Paste Mask layer (to avoid the requirement
> to import Gerber files produced from these layers into a previously
> blank/new PCB file in order to acquire such a count)? I am still working
> (with assistance from Ian Wilson) on a PCB inverting server, but this is
> something that I could do at some stage, *if* there was sufficient user
> interest.
>
> Regards,
> Geoff Harland.
> -----------------------------
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