Jimmy,
        At the last place I worked, we were trying to do something very
similar with verifying land patterns for large QFP devices. Between the Data
sheets and the CAD automatic conversion from mm to inches (can you say
rounding off error) we went to placing the devices on the plots. We very
quickly found that our Laser-Jets and Design-Jets (and every other plotters
we could find in the company) had a long axis error, we concluded that the
was combination of paper/film creep and stepper motor tolerances. Of coarse
the short axis within a mil-of-perfect so, we rotated the device and plotted
the other axis (along with correcting the dimensional errors). This allowed
us to get the pattern close. After that we sent it to the photo-plotter for
one last check. I agree with Ray that these plotters and printers are great
and color plots are the way to go. With your statement about wanting to
overlay "plots" on to the board I was reminded of the hassles that we went
through. If this (overlays plots on a board) is the ultimate objective, then
accuracy will be an issue and don't forget the FAB allowances on the board.
Accuracy "can" cost big bucks.
Best of Luck,
Russel W. Pringle, C.I.D.
Halliburton Energy Services
Wireline Development
(281) 596-6620   Fax: (281) 596-4279
[log in to unmask] <mailto:[log in to unmask]>

        -----Original Message-----
        From:   Ray Humphrey [SMTP:[log in to unmask]]
        Sent:   Thursday, October 07, 1999 9:26 PM
        To:     [log in to unmask]
        Subject:        Re: [DC] Looking for a photoplotter (part 2)

        Jimmy,
        Many modern printers and plotters will do what you need.  I use an
HP
        DesignJet 650C, which will plot on a variety of paper types plus
inkjet film
        and vellum.  InkJet printers will handle glossy film and
transparencies,
        too.  Then benefit of using one of these options, rather than a
        photoplotter, is that you can get your film printed in color, if you
like.
        The quality is very good with the cost being very low.  Some
laserjets will
        also handle transparent films.

        Ray

        ----- Original Message -----
        From: Jimmy Blier <[log in to unmask]>
        To: <[log in to unmask]>
        Sent: Thursday, October 07, 1999 6:23 PM
        Subject: [DC] Looking for a photoplotter (part 2)


        > Hi Tom,
        >
        > I think I might have been unclear when I asked my question.
        > I'm looking for a printer that does films, just like the one your
films
        > manufacture does but ((((cheaper!!!))))
        > I'm not looking for a (Fire 9000) are anything in that caliber.
All I
        want
        > is just a way to print films on a clear plastic sheet with a
reasonable
        > precision and reliability.
        >
        > We want to superpose to films over our incoming PCB's to verify in
the
        > manufacture is doing everything as they should. We made some tests
and so
        > far it looks very promising.   We can verify the soldermask,
traces,
        > silkscreen and drill sizes in the blink of an eye.  But we don't
want the
        > rely on a local film factory to generate the films for our boards
made in
        > Hong Kong, we want this a bit more home made.  :)
        >
        > Cheers,
        >
        > Jimmy Blier
        > CAD Department. (Supervisor)
        > P A R A D O X
        > S E C U R I T Y        S Y S T E M S
        > Email: [log in to unmask]
        > Phone:  (450) 491-7444
        > Fax:  (450) 491-5940
        >