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Engraving: EagleCad with CNC conversion

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  • bill_d_100
    You can also download the shareware version of EagleCad (yeah the PCB layout software) and do simple text/figure engraving with that. They have a ULP macro
    Message 1 of 12 , Jun 1, 2005
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      You can also download the shareware version of EagleCad (yeah the PCB
      layout software) and do simple text/figure engraving with that. They
      have a ULP macro that converts a board layout to g-code. So if you
      make your board file consist of just text, you engrave text.
      I have done that with a MaxNC and v-bits from Think&Tinker.
      If you use the vector font, th g-code is small also. And I think you
      automatically get 2 passes on the text because it is trying to do
      outlines... it has been a while, this is from an addled memory. I
      remember just setting the outline separation to something very small
      like 0.0001 to get twice passed text.
      If anyone is interested I can dig up the details...
      Bill
    • vks_generic
      Sounds like you have some experience with PCB milling. May I ask you (or anyone else who is familiar with PCB milling) a question? What is the smallest track
      Message 2 of 12 , Jul 13 2:45 PM
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        Sounds like you have some experience with PCB milling. May I ask you
        (or anyone else who is familiar with PCB milling) a question? What is
        the smallest track width/isolation width that you are able to acheive
        using your mill? I resorted to grinding my own carbide cutters, and
        that allowed me to go down to about 0.028" isolation, but I need
        0.012, more than a factor of two smaller. Is it just plain not worth
        the effort because I won't be able to get that fine of detail anyway,
        and I should go back to photo etching? Or are 0.012" cuts acheivable?
        If so, how?

        Thanks,

        Vlad

        --- In taigtools@yahoogroups.com, "bill_d_100" <dreschel@i...> wrote:
        > You can also download the shareware version of EagleCad (yeah the PCB
        > layout software) and do simple text/figure engraving with that. They
        > have a ULP macro that converts a board layout to g-code. So if you
        > make your board file consist of just text, you engrave text.
        > I have done that with a MaxNC and v-bits from Think&Tinker.
        > If you use the vector font, th g-code is small also. And I think you
        > automatically get 2 passes on the text because it is trying to do
        > outlines... it has been a while, this is from an addled memory. I
        > remember just setting the outline separation to something very small
        > like 0.0001 to get twice passed text.
        > If anyone is interested I can dig up the details...
        > Bill
      • Codesuidae
        ... Have you tried using a V-tip engraving cutter? I don t know the sizes off the top of my head, but you can get pretty fine details doing it that way. Dave
        Message 3 of 12 , Jul 14 9:37 AM
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          vks_generic wrote:

          >Sounds like you have some experience with PCB milling. May I ask you
          >(or anyone else who is familiar with PCB milling) a question? What is
          >the smallest track width/isolation width that you are able to acheive
          >using your mill? I resorted to grinding my own carbide cutters, and
          >that allowed me to go down to about 0.028" isolation, but I need
          >0.012, more than a factor of two smaller.
          >
          Have you tried using a V-tip engraving cutter? I don't know the sizes
          off the top of my head, but you can get pretty fine details doing it
          that way.

          Dave
        • vks_generic
          Thank you for your suggestion. Yes, essentially I did use a V-tip cutter, but not an engraving one. I could not find one for sale with the tip small enough for
          Message 4 of 12 , Jul 14 12:24 PM
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            Thank you for your suggestion. Yes, essentially I did use a V-tip
            cutter, but not an engraving one. I could not find one for sale with
            the tip small enough for my needs (and yet at a reasonable price),
            plus copper clad boards tend to be a little bent and warped which
            makes the V-tip cutter sometimes cut deeper and sometimes shallower,
            in essense creating isolation traces that are sometimes wider and
            sometimes narrower than expected.

            I created a fairly precise grinding machine by mounting a dremsl on my
            lathe's crossslide and ground V-tip cutters out of broken 1/8" carbide
            drill bit shanks. I ground the very tip at about 60 degrees followed
            by ~0.05" section that is 0.028" in diameter. The idea is that the
            V-shaped part will always sink just before the copper surface, and the
            0.028" part will be cutting through copper, thus resulting in a
            uniform trace with, even if the PCB board is not perfectly flat and
            the depth of cut varies. That worked pretty well. However, when I
            started trying to grind smaller and smaller diameters, my cutters
            became more and more fragile, often breaking before I was even done
            grinding. Of course, I know little to nothing about grinding carbide,
            so maybe I am doing something very wrong. I just did not have the
            heart to shell out 20-50 bucks for a small professionally-ground
            cutter just to snap it right away, or dull it too quickly because of
            slow spindle speed and feed.

            In short, I cannot mill isolation traces smaller than 0.02 in width
            with my self-made cutters. And I wanted to know if anyone had more
            success with professionally ground ones, or if it will be a waste of
            time to actually go out and by one. I know there are lots of other
            potential showstoppers, mostly due to slow taig spindle speed and lack
            of flatness in copper clad boards, but are they REAL showstoppers, or
            have someone managed to mill boards with isolation traces to the tune
            of 0.012" or so?

            Thanks for any feedback,

            Vlad

            --- In taigtools@yahoogroups.com, Codesuidae <codesuidae@c...> wrote:
            > vks_generic wrote:
            >
            > >Sounds like you have some experience with PCB milling. May I ask you
            > >(or anyone else who is familiar with PCB milling) a question? What is
            > >the smallest track width/isolation width that you are able to acheive
            > >using your mill? I resorted to grinding my own carbide cutters, and
            > >that allowed me to go down to about 0.028" isolation, but I need
            > >0.012, more than a factor of two smaller.
            > >
            > Have you tried using a V-tip engraving cutter? I don't know the sizes
            > off the top of my head, but you can get pretty fine details doing it
            > that way.
            >
            > Dave
          • jensen_remote
            I can confirm that the taig will do 0.012 traces with a half-round v-tip cutter. You have to be very picky about zeroing the z axis. Cut to a depth of 0.006
            Message 5 of 12 , Jul 14 1:04 PM
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              I can confirm that the taig will do 0.012" traces with a half-round
              v-tip cutter. You have to be very picky about zeroing the z axis.
              Cut to a depth of 0.006 and you're good. I turn off backlash
              compensation in the controller software when doing PCBs. Also, make
              sure the PCB is screwed or clamped down very flat.

              The EagleCad web site has a user language program in the downloads
              section called "pcb-gcode" which works well. I had to modify it
              slightly to make it work with Mach2, but the changes were minor.


              Cheers,

              -Peter
            • Codesuidae
              ... Why do you do this? CS
              Message 6 of 12 , Jul 14 2:58 PM
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                jensen_remote wrote:

                >I turn off backlash compensation in the controller software when doing PCBs.
                >
                Why do you do this?

                CS
              • Tom Harrison
                ... Have you considered a vacuum hold down plate for the board, or are they so warped that not even that works? [Non-text portions of this message have been
                Message 7 of 12 , Jul 15 12:25 AM
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                  At 7/14/2005 12:24 PM, you wrote:

                  >plus copper clad boards tend to be a little bent and warped which
                  >makes the V-tip cutter sometimes cut deeper and sometimes shallower,

                  Have you considered a vacuum hold down plate for the board, or are they so
                  warped that not even that works?

                  [Non-text portions of this message have been removed]
                • ibeenew2
                  ... You can make a solid picture frame to press down over the full board perimeter, I had to do this with some super thin woods that were twisted. In that
                  Message 8 of 12 , Jul 15 1:46 AM
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                    > plus copper clad boards tend to be a little bent and warped which
                    > makes the V-tip cutter sometimes cut deeper and sometimes shallower,

                    You can make a solid picture frame to press down over the full board perimeter, I had to do
                    this with some super thin woods that were twisted. In that case some strips of wood on top
                    and a flat backing were enough. The frame can also be used as a fixture if you are doing
                    multiple boards.

                    BP
                  • jensen_remote
                    Engraving PCBs is easy to do at all, but hard to do perfectly. I said earlier that I can do 0.012 wide traces, and that is true. It is also true that those
                    Message 9 of 12 , Jul 15 2:43 PM
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                      Engraving PCBs is easy to do at all, but hard to do perfectly. I
                      said earlier that I can do 0.012 wide traces, and that is true. It is
                      also true that those traces do vary somewhat in thickenss, mostly due
                      to the board being slightly warped, possibly also due to some
                      backlash. That said, they don't vary so much as to matter to the
                      electrons going thru them :)

                      I do have a custom fixture which holds down the board on all sides,
                      as was suggested in this thread. That handles most of the board
                      warpage problems.

                      I turn off the backlash compensation because compensation seems to
                      cause more problems than it solves. Maybe I'm measuring backlash
                      incorrectly... I use Mach2 on a VERY slow machine, and some of my
                      problems with backlash and acceleration seem to have something to do
                      with Mach2 and not the Taig. I really should buy a faster machine,
                      once the money falls from the sky :)

                      Anyway, play around with 60 degree V cutters. They work well for
                      PCBs. Take a look on e-bay at item number 7515253220 for a cheap way
                      to get started (no affiliation with this company, but I have used
                      these cutters for PCBs).

                      Cheers,

                      -Peter
                    • vks_generic
                      yes, I have, and I may still do that. In general I have been trying to avoid the vacuum solution for a couple of reasons - it would be a little bulky and
                      Message 10 of 12 , Jul 15 4:08 PM
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                        yes, I have, and I may still do that. In general I have been trying to
                        avoid the vacuum solution for a couple of reasons
                        - it would be a little bulky and cumbersome, and would make it a
                        little harder to keep the board perpendicular to the spindle. Not
                        impossible, but harder.
                        - can't drill holes until I remove the vacuum contraption
                        - not sure how well it'll stick when I am done with milling one side,
                        and need to flip it over and mill the other. The bottom side is no
                        longer smooth.
                        - I usually drill holes before milling the second side, this helps in
                        alignment of the board. I can't drill holes if I have a vacuum plate,
                        making alignment more difficult.

                        All in all warping is really not that bad, at least for boards of my
                        size, so it's not my most immediate problem that I'd like to address.
                        Thanks for the suggestion though.

                        Vlad

                        --- In taigtools@yahoogroups.com, Tom Harrison <TomH-CNC@T...> wrote:
                        > At 7/14/2005 12:24 PM, you wrote:
                        >
                        > >plus copper clad boards tend to be a little bent and warped which
                        > >makes the V-tip cutter sometimes cut deeper and sometimes shallower,
                        >
                        > Have you considered a vacuum hold down plate for the board, or are
                        they so
                        > warped that not even that works?
                        >
                        > [Non-text portions of this message have been removed]
                      • vks_generic
                        Thank you Peter, you totally answered my question. Vlad
                        Message 11 of 12 , Jul 15 4:12 PM
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                          Thank you Peter, you totally answered my question.

                          Vlad

                          --- In taigtools@yahoogroups.com, "jensen_remote" <jensen_remote@y...>
                          wrote:
                          >
                          > Engraving PCBs is easy to do at all, but hard to do perfectly. I
                          > said earlier that I can do 0.012 wide traces, and that is true. It is
                          > also true that those traces do vary somewhat in thickenss, mostly due
                          > to the board being slightly warped, possibly also due to some
                          > backlash. That said, they don't vary so much as to matter to the
                          > electrons going thru them :)
                          >
                          > I do have a custom fixture which holds down the board on all sides,
                          > as was suggested in this thread. That handles most of the board
                          > warpage problems.
                          >
                          > I turn off the backlash compensation because compensation seems to
                          > cause more problems than it solves. Maybe I'm measuring backlash
                          > incorrectly... I use Mach2 on a VERY slow machine, and some of my
                          > problems with backlash and acceleration seem to have something to do
                          > with Mach2 and not the Taig. I really should buy a faster machine,
                          > once the money falls from the sky :)
                          >
                          > Anyway, play around with 60 degree V cutters. They work well for
                          > PCBs. Take a look on e-bay at item number 7515253220 for a cheap way
                          > to get started (no affiliation with this company, but I have used
                          > these cutters for PCBs).
                          >
                          > Cheers,
                          >
                          > -Peter
                        • Tom Harrison
                          Now, mind you, I haven t tried this yet, but I was about to use this technique myself. I would have thought a stack of particle board would do the trick, with
                          Message 12 of 12 , Jul 15 6:48 PM
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                            Now, mind you, I haven't tried this yet, but I was about to use this
                            technique myself.

                            I would have thought a stack of particle board would do the trick, with the
                            top piece drilled through for a vacuum matrix, the bottom of that sheet
                            grooved for connection to a Shop-Vac or similar high-flow, high-suction
                            vacuum cleaner . After construction, use a fly cutter on top to flatten to
                            the spindle. After first trace pass, drill just two holes for alignment, at
                            far points in opposite corners. Remove the board, use a mirroring of the
                            hole pattern to drill the vacuum plate to pin the board in place, and mount
                            board upside down on pins for second pass. After trace pass, drill
                            remaining holes. The extra holes in the vacuum plate don't matter much, but
                            if you don't drill too deep, just slice off a small layer of the platen to
                            refresh it.

                            Am I being naive, since I'm more or less just guessing?

                            Tom Harrison

                            At 7/15/2005 04:08 PM, you wrote:
                            >yes, I have, and I may still do that. In general I have been trying to
                            >avoid the vacuum solution for a couple of reasons
                            >- it would be a little bulky and cumbersome, and would make it a
                            >little harder to keep the board perpendicular to the spindle. Not
                            >impossible, but harder.
                            >- can't drill holes until I remove the vacuum contraption
                            >- not sure how well it'll stick when I am done with milling one side,
                            >and need to flip it over and mill the other. The bottom side is no
                            >longer smooth.
                            >- I usually drill holes before milling the second side, this helps in
                            >alignment of the board. I can't drill holes if I have a vacuum plate,
                            >making alignment more difficult.
                            >
                            >All in all warping is really not that bad, at least for boards of my
                            >size, so it's not my most immediate problem that I'd like to address.
                            >Thanks for the suggestion though.
                            >
                            >Vlad
                            >
                            >--- In taigtools@yahoogroups.com, Tom Harrison <TomH-CNC@T...> wrote:
                            > > At 7/14/2005 12:24 PM, you wrote:
                            > >
                            > > >plus copper clad boards tend to be a little bent and warped which
                            > > >makes the V-tip cutter sometimes cut deeper and sometimes shallower,
                            > >
                            > > Have you considered a vacuum hold down plate for the board, or are
                            >they so
                            > > warped that not even that works?
                            > >
                            > > [Non-text portions of this message have been removed]
                            >
                            >
                            >
                            >
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