Loading ...
Sorry, an error occurred while loading the content.

Re: Is this the right tool for the job?

Expand Messages
  • montanaaardvark
    Marcus, Yes, I think that does help. I think I can envision what you re doing, which seems to be half the battle. Bob ... not work ... substitute) and ... for
    Message 1 of 10 , Feb 1, 2004
    • 0 Attachment
      Marcus,


      Yes, I think that does help. I think I can envision what you're
      doing, which seems to be half the battle.



      Bob


      --- In SherlineCNC@yahoogroups.com, "Marcus and Eva" <implmex@a...>
      wrote:
      > Hi Bob:
      > I have access to some pretty pricey software so my method will
      not work
      > for you if you can't come up with some similar options.
      > I do my modelling in Solidworks (Rhino would be a reasonable
      substitute) and
      > my programming in Mastercam (Vector might be a good alternative
      for you).
      > I'd stand the ring blank up on a mandrel in a simple fixture that
      allows me
      > to rotate the mandrel accurately by 180 degrees at a time.
      > I'd program the ring in two halves, first the half with the
      engraving panel
      > facing up, and then the other side.
      > I'd avoid trying to program it as a 4th axis job...it's neither
      necessary
      > nor more productive than doing it as a straightforward 3 axis job
      with a
      > single index.
      > I'd gang a whole bunch of blanks up on my mandrel and cut them all
      as a
      > batch.
      > This would be a surfacing job, but I'd rough out the basic profile
      as a 3D
      > contour, with the biggest cutter I could crowd between the blanks.
      > The mandrel would need to be undercut a bit more than 1/2 the
      cutter
      > diameter.
      > The next step would be surface milling, again with the biggest
      ball cutter
      > that will get into all the corners.
      > Say a 1/8" diameter cutter with a 0.030 stepover and a 0.010" stock
      > allowance.
      > Then I'd finish cut with the same cutter at 0.0075" stepover and
      the fastest
      > feedrate I can get away with, say 40 IPM.
      > (anything much faster and the machine starts to hump around on the
      floor
      > from all the fast direction changes).
      > If I got orders for more than 50 a month of these, I'd make up a
      really nice
      > master in brass on the CNC, and then build a rubber mold and shoot
      my waxes
      > in the conventional way, rather than trying to cut them.
      > I'd probably put half a dozen or so on a sprue button and cast as
      a batch,
      > unless I had one of those super $12,000.00 inert atmosphere vacuum
      > casters...then I'd cram my flask just about as full as I could get
      it.
      > That's it in a nutshell, Bob...hope it helps.
      > Cheers
      >
      > Marcus
      >
      >
    • Andrew Werby
      Message: 2 Date: Fri, 30 Jan 2004 23:22:09 -0000 From: montanaaardvark Subject: Re: Is this the right tool for the job? Marcus,
      Message 2 of 10 , Feb 1, 2004
      • 0 Attachment
        Message: 2
        Date: Fri, 30 Jan 2004 23:22:09 -0000
        From: "montanaaardvark" <boblombardi@...>
        Subject: Re: Is this the right tool for the job?


        Marcus,


        Actually, it works out that my choice of styles is probably very CNC-
        able (is that a word?). I lean toward what I think is called
        architectural - clean lines with minimal frills or filigrees, high
        polish as opposed to fancy textures. One of my motivations is that
        I became a lapidary and have all these fantastic stones, but when
        you look for men's jewelry it's incredibly boring.

        [That's certainly true - if you're about to change that, more power to you.]

        So no, I'm not likely to want to do something like the Eagle with a
        bazillion fine details and changing over to .002 diameter end mills.

        How about this? How would you go about designing something like a
        simple engraved-initial ring? Something like a plain band but with
        a wider, flat top that you engrave an initial on. I'm sure you've
        seen this type of design a hundred times in various catalogs. The
        challenge would be to get the basic ring shape carved under CNC
        control rather than by hand.

        Thanks for your input,
        Bob

        [If you've got a 4th axis, then one way to go would be to start with a ring
        tube (Ferris File-a-Wax comes this way) held by an expanding mandrel inside.
        Use a sacrificial layer of thin plastic sheet wrapped over the mandrel to
        keep from scarring it when the cutters break through the wax. I usually
        rough things out using a routine that sends the cutter down the X-axis,
        increments in A, then moves back up X. I then finish with a cut that goes
        all the way around the part, then increments in X, and repeats. DeskProto
        allows you to do this fairly automatically. You will probably want to add
        some "bridges" that will hold the ring model to the rest of the tube, so it
        isn't cut completely free- this can cause damage.

        The other way is to cut it from one side of a block, then flip it over and
        cut the other side. You'd also want to add some supports to the rest of the
        block. DeskProto has a "2-side wizard" that makes the registration of the
        two sides pretty straightforward.

        Either way you do it, you shouldn't expect the CNC process to give you a
        perfect master; it will need some manual touchup before it's ready to cast
        and polish, but it can get you close. I agree that some designs are more
        "CNC-able" than others, but organic textural sorts of things (even eagles)
        are certainly possible, if you use a modern CAM program, your mill is
        reasonably tight, and the spindle can spin small cutters fast enough.

        You can try DeskProto for free for a month; the downloadable trial version
        will post code, and postprocessors are included. Get it from
        http://www.deskproto.com/download/trialversion.htm . Give it a shot and let
        us know how it works for you.]





        - In SherlineCNC@yahoogroups.com, "Marcus and Eva" <implmex@a...>
        wrote:
        > Hi Bob:
        > Did you have a particular design style in mind?
        > I ask this because I've noticed that a lot of people seem to be
        under the
        > impression that CNC will cut any shape you care to envision, and
        that it
        > will do so with impeccable fidelity in the most complex of
        contours.
        > That ain't true!!!

        [There are things it's not suited for, but complex surfaces are certainly
        possible.]

        > CNC is great if you like to make designs that lend themselves
        readily to
        > programming and nibbling out with cutters, Dan Statman's work is an
        > excellent example of this.
        > Unfortunately, often times you'll see a CNC advertising brochure
        where the
        > machine is nibbling out the shape of an eagle or some other such
        freeform
        > shape with tons of detail in it.

        > CNC is a terrible choice for that kind of work if you ever hope to
        make any
        > money at it.
        > The programming takes DAYS of work on high end software, and the G
        code
        > files are HUGE with tons of toolchanges and relatively poor
        outcomes if you
        > need crisp, tiny, sharp-cornered details.

        [I think you might be surprised by the ease of use and capabilities of some
        modern CAM programs. They aren't extraordinarily expensive anymore, and the
        programming of toolpaths for sculptural reliefs takes minutes, not days. I
        rarely use more than one toolchange; one ballnose cutter for roughing and a
        smaller one for finishing. Sharp inside corners are a problem any time you
        are using rotary tools, but cleaning these up by hand with a graver, if you
        need them, isn't as hard as carving the whole project.]

        > I can make a rubber mold from a freehand engraved and carved
        master a
        > million times quicker than I could ever program a job like that,
        and I can
        > shoot waxes a billion times quicker.
        > They'll be better looking waxes too!!!

        [Producing a master pattern using CNC (with hand touch-up if necessary),
        molding it, and casting duplicates is a good way of using the process. I
        don't think that it's any slower to make the mold or cast the waxes if you
        start with a CNC-produced master.]

        > So think carefully about what kind of designs you like to
        make...if they're
        > good CNC jobs then go for it...you'll have lots of fun.
        > Cheers
        >
        > Marcus

        [We're in agreement here...]

        Andrew Werby
        www.computersculpture.com
      • zelcnc
        I would make a two part set up. mill your letters in flat wax. then use an end mill to cut out the shape you want. you could to do several on one sheet. then
        Message 3 of 10 , Feb 1, 2004
        • 0 Attachment
          I would make a two part set up. mill your letters in flat wax. then
          use an end mill to cut out the shape you want. you could to do
          several on one sheet. then mount the cutouts on a wax band and your
          done.
          sean
          --- In SherlineCNC@yahoogroups.com, "montanaaardvark"
          <boblombardi@c...> wrote:
          >
          > Marcus,
          >
          >
          > Yes, I think that does help. I think I can envision what you're
          > doing, which seems to be half the battle.
          >
          >
          >
          > Bob
          >
          >
          > --- In SherlineCNC@yahoogroups.com, "Marcus and Eva" <implmex@a...>
          > wrote:
          > > Hi Bob:
          > > I have access to some pretty pricey software so my method
          will
          > not work
          > > for you if you can't come up with some similar options.
          > > I do my modelling in Solidworks (Rhino would be a reasonable
          > substitute) and
          > > my programming in Mastercam (Vector might be a good alternative
          > for you).
          > > I'd stand the ring blank up on a mandrel in a simple fixture that
          > allows me
          > > to rotate the mandrel accurately by 180 degrees at a time.
          > > I'd program the ring in two halves, first the half with the
          > engraving panel
          > > facing up, and then the other side.
          > > I'd avoid trying to program it as a 4th axis job...it's neither
          > necessary
          > > nor more productive than doing it as a straightforward 3 axis job
          > with a
          > > single index.
          > > I'd gang a whole bunch of blanks up on my mandrel and cut them
          all
          > as a
          > > batch.
          > > This would be a surfacing job, but I'd rough out the basic
          profile
          > as a 3D
          > > contour, with the biggest cutter I could crowd between the blanks.
          > > The mandrel would need to be undercut a bit more than 1/2 the
          > cutter
          > > diameter.
          > > The next step would be surface milling, again with the biggest
          > ball cutter
          > > that will get into all the corners.
          > > Say a 1/8" diameter cutter with a 0.030 stepover and a 0.010"
          stock
          > > allowance.
          > > Then I'd finish cut with the same cutter at 0.0075" stepover and
          > the fastest
          > > feedrate I can get away with, say 40 IPM.
          > > (anything much faster and the machine starts to hump around on
          the
          > floor
          > > from all the fast direction changes).
          > > If I got orders for more than 50 a month of these, I'd make up a
          > really nice
          > > master in brass on the CNC, and then build a rubber mold and
          shoot
          > my waxes
          > > in the conventional way, rather than trying to cut them.
          > > I'd probably put half a dozen or so on a sprue button and cast as
          > a batch,
          > > unless I had one of those super $12,000.00 inert atmosphere vacuum
          > > casters...then I'd cram my flask just about as full as I could
          get
          > it.
          > > That's it in a nutshell, Bob...hope it helps.
          > > Cheers
          > >
          > > Marcus
          > >
          > >
        • Marcus and Eva
          Hi Andrew: I find your comments very interesting...we obviously have a somewhat different approach to the creative process and it s most efficient or
          Message 4 of 10 , Feb 1, 2004
          • 0 Attachment
            Hi Andrew:
            I find your comments very interesting...we obviously have a somewhat
            different approach to the creative process and it's most efficient or
            pleasureable implementation, but we are in good agreement on the
            fundamentals.
            The point I was trying to make to Bob, and to others who are interested, is
            that the CNC process is often advertised as almost magical in its ability to
            do anything, and that the process consists of "nothing more" than quickly
            creating a beautiful model on CAD and then dumping it into the magic
            machine, to whip out the goods and make everyone a rich and happy camper.
            Of course, as you and I both know from experience, it ain't quite so.
            I'm a modelling (clay) and hand carving kind of guy...I can do it quickly
            and well, so I create more intuitively that way.
            Others I've met, and I'm sure you're among them, have the tools, the
            experience to use them, and the creative bent to make it happen in the CAD
            program...that's great, but it is not nearly as easy to do as it appears
            when a casual look is taken at a master at work.

            For a guy who is just starting out in this game, that's important
            information to know, and the risk is that expensive tools and equipment are
            going to be bought to try and make it work in a style that's intrinsically
            better suited to a different fabrication process.
            The ubiquitous eagle motif is a typical example...I've always found it
            misleading and a bit dishonest of the CNC vendors to tout it as a "typical"
            example of the capabilities of the process.
            Now, that's obviously not to say that it can't be done, and that the vendors
            are somehow "lying" about the abilities of the machine, but my point remains
            that the acquisition of the machine will not make the eagle magically just
            happen, and that even if it does eventually appear, that it's not
            necessarily a good way to do it.
            If I've got to create that eagle from scratch and have it cast, ready for
            finishing in 4 hours or so, I'm not so sure I'd be reaching for the CAD
            program.
            On the other hand, if my need was for exquisite symmetry of some shape..it'd
            be worth it in my book to do the job in CAD.
            Similarly, if I needed precision in a shape, and I could define the shape
            well in CAD without the need to digitize..it'd be a worthwhile undertaking
            for me.
            Last, if I needed to exploit a material for repetitive work, that can't be
            cast but can be cut, or my design was enhanced by the "machined" look, I'd
            CAD CAM it too.
            That's my personal take on it, for what it's worth.
            Cheers

            Marcus

            ----- Original Message -----
            From: "Andrew Werby" <a.werby@...>
            To: <SherlineCNC@yahoogroups.com>
            Cc: <boblombardi@...>
            Sent: Sunday, February 01, 2004 11:29 AM
            Subject: [SherlineCNC] Re: Is this the right tool for the job?


            >
            > Message: 2
            > Date: Fri, 30 Jan 2004 23:22:09 -0000
            > From: "montanaaardvark" <boblombardi@...>
            > Subject: Re: Is this the right tool for the job?
            >
            >
            > Marcus,
            >
            >
            > Actually, it works out that my choice of styles is probably very CNC-
            > able (is that a word?). I lean toward what I think is called
            > architectural - clean lines with minimal frills or filigrees, high
            > polish as opposed to fancy textures. One of my motivations is that
            > I became a lapidary and have all these fantastic stones, but when
            > you look for men's jewelry it's incredibly boring.
            >
            > [That's certainly true - if you're about to change that, more power to
            you.]
            >
            > So no, I'm not likely to want to do something like the Eagle with a
            > bazillion fine details and changing over to .002 diameter end mills.
            >
            > How about this? How would you go about designing something like a
            > simple engraved-initial ring? Something like a plain band but with
            > a wider, flat top that you engrave an initial on. I'm sure you've
            > seen this type of design a hundred times in various catalogs. The
            > challenge would be to get the basic ring shape carved under CNC
            > control rather than by hand.
            >
            > Thanks for your input,
            > Bob
            >
            > [If you've got a 4th axis, then one way to go would be to start with a
            ring
            > tube (Ferris File-a-Wax comes this way) held by an expanding mandrel
            inside.
            > Use a sacrificial layer of thin plastic sheet wrapped over the mandrel to
            > keep from scarring it when the cutters break through the wax. I usually
            > rough things out using a routine that sends the cutter down the X-axis,
            > increments in A, then moves back up X. I then finish with a cut that goes
            > all the way around the part, then increments in X, and repeats. DeskProto
            > allows you to do this fairly automatically. You will probably want to add
            > some "bridges" that will hold the ring model to the rest of the tube, so
            it
            > isn't cut completely free- this can cause damage.
            >
            > The other way is to cut it from one side of a block, then flip it over and
            > cut the other side. You'd also want to add some supports to the rest of
            the
            > block. DeskProto has a "2-side wizard" that makes the registration of the
            > two sides pretty straightforward.
            >
            > Either way you do it, you shouldn't expect the CNC process to give you a
            > perfect master; it will need some manual touchup before it's ready to cast
            > and polish, but it can get you close. I agree that some designs are more
            > "CNC-able" than others, but organic textural sorts of things (even eagles)
            > are certainly possible, if you use a modern CAM program, your mill is
            > reasonably tight, and the spindle can spin small cutters fast enough.
            >
            > You can try DeskProto for free for a month; the downloadable trial version
            > will post code, and postprocessors are included. Get it from
            > http://www.deskproto.com/download/trialversion.htm . Give it a shot and
            let
            > us know how it works for you.]
            >
            >
            >
            >
            >
            > - In SherlineCNC@yahoogroups.com, "Marcus and Eva" <implmex@a...>
            > wrote:
            > > Hi Bob:
            > > Did you have a particular design style in mind?
            > > I ask this because I've noticed that a lot of people seem to be
            > under the
            > > impression that CNC will cut any shape you care to envision, and
            > that it
            > > will do so with impeccable fidelity in the most complex of
            > contours.
            > > That ain't true!!!
            >
            > [There are things it's not suited for, but complex surfaces are certainly
            > possible.]
            >
            > > CNC is great if you like to make designs that lend themselves
            > readily to
            > > programming and nibbling out with cutters, Dan Statman's work is an
            > > excellent example of this.
            > > Unfortunately, often times you'll see a CNC advertising brochure
            > where the
            > > machine is nibbling out the shape of an eagle or some other such
            > freeform
            > > shape with tons of detail in it.
            >
            > > CNC is a terrible choice for that kind of work if you ever hope to
            > make any
            > > money at it.
            > > The programming takes DAYS of work on high end software, and the G
            > code
            > > files are HUGE with tons of toolchanges and relatively poor
            > outcomes if you
            > > need crisp, tiny, sharp-cornered details.
            >
            > [I think you might be surprised by the ease of use and capabilities of
            some
            > modern CAM programs. They aren't extraordinarily expensive anymore, and
            the
            > programming of toolpaths for sculptural reliefs takes minutes, not days. I
            > rarely use more than one toolchange; one ballnose cutter for roughing and
            a
            > smaller one for finishing. Sharp inside corners are a problem any time you
            > are using rotary tools, but cleaning these up by hand with a graver, if
            you
            > need them, isn't as hard as carving the whole project.]
            >
            > > I can make a rubber mold from a freehand engraved and carved
            > master a
            > > million times quicker than I could ever program a job like that,
            > and I can
            > > shoot waxes a billion times quicker.
            > > They'll be better looking waxes too!!!
            >
            > [Producing a master pattern using CNC (with hand touch-up if necessary),
            > molding it, and casting duplicates is a good way of using the process. I
            > don't think that it's any slower to make the mold or cast the waxes if you
            > start with a CNC-produced master.]
            >
            > > So think carefully about what kind of designs you like to
            > make...if they're
            > > good CNC jobs then go for it...you'll have lots of fun.
            > > Cheers
            > >
            > > Marcus
            >
            > [We're in agreement here...]
            >
            > Andrew Werby
            > www.computersculpture.com
            >
            >
            >
            >
            >
            >
            > Yahoo! Groups Links
            >
            > To visit your group on the web, go to:
            > http://groups.yahoo.com/group/SherlineCNC/
            >
            > To unsubscribe from this group, send an email to:
            > SherlineCNC-unsubscribe@yahoogroups.com
            >
            > Your use of Yahoo! Groups is subject to:
            > http://docs.yahoo.com/info/terms/
            >
            >
          Your message has been successfully submitted and would be delivered to recipients shortly.