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CNC and manufacturing facilities

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  • Neil Gaunt
    ... I think that this has great potential, and if I can help I will be delighted. I came into Z because I like the potential for realistic operation (long
    Message 1 of 3 , Dec 2, 2003
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      Kim wrote:

      >I don't want to bring your enthusiasm down but I feel what we
      >currently lack in building Z scale anything is either casting or
      >injection molding. Some level of detail can be obtained by Photo
      >etching, but none of the lathe and end mills can get to the level of
      >detail that casting or injection molding gets.....

      >I own a 4 axis CNC Mill and CNC Lathe and access
      >to most CAD software. The only things I can build for Z loco are some
      >parts for the drive mechanism, even making the gears right is
      >extremely time consuming, so I use Marklin gears and drive mechanism.

      >If we could find an artist like Yuji who could make a master
      >mould in styrene or wax or resin then it could be reproduced in
      >Brass, add some PE details and use some CNC for making the chassis
      >and drive mechanism parts and you have a working loco.

      >So in order of priority I would say Casting, Photo Etch, CNC
      >machining, decal making and painting. The CNC parts could also be
      >eventually cast.

      I think that this has great potential, and if I can help I will be
      delighted. I came into Z because I like the potential for realistic
      operation (long trains and scale lencth coaches plus spacious scenery), and
      also (masochistically) because I felt overwhelmed by the vast amount of
      OO/HO and N material available. This I am starting to develop British and
      African subjects and the possibility of cooperation on CNC is a big step
      forward.

      As my company has manifactured model aircraft for quite a while we have the
      following processes available NOW:

      Resin casting
      White metal casting
      Vacuum forming
      Photo etch
      Decal origination and printing

      We are discontinuing injection moulding because of the high cost of tooling.

      If anyone from those with a CNC interest would like to cooperate please
      contact me off line.

      Neil Gaunt
    • jim_manley_alpha_six
      Happy Early WedneZday, YouZ All, For the slower readers (such as myself) and those who actually have a life, here s what s in the inaugural issue of The Daily
      Message 2 of 3 , Dec 3, 2003
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        Happy Early WedneZday, YouZ All,

        For the slower readers (such as myself) and those who actually
        have a life, here's what's in the inaugural issue of "The Daily Z
        Scale Computer-Assisted Fabrication (CAF) Picayune Times
        Chronicle Intelligencer (CAFPTCI)":

        - CAF Just One of Many Complementary Z Scale Modeling
        Techniques
        - Potential CAF Techniques to Investigate for Z Scale
        - Resolution and Repeatability Limits in CAF for Z Scale
        - Additional CAF Technologies
        - CAF in the Z Scale Modeling Workflow
        - May Need to Start Marketplace to Facilitate Parts Exchange
        - Fabricating and Operating Large Z Scale Stock for Typical
        Layouts


        - CAF Just One of Many Complementary Z Scale Modeling
        Techniques

        In response to the comments received thus far, I've changed the
        name of what I'm talking about to Computer-Assisted Fabrication
        (CAF) so as to encompass any automated technique, to include
        CNC milling machines, lathes, drill presses, saws, molecular
        compilers (now that _would_ deserve its own group list! ;) and
        who-knows-what-else in the future. I didn't intend to imply that
        CAF was the only technique we might use to create parts and
        products, just one of the more recent and hopefully, faster
        (maybe, maybe not) and more accurate, step in the process. I
        do recognize that there is a heck of a lot of finishing that needs to
        be done after milling and lathe work. It seems that STEP intends
        to eventually address all of the steps in production, but I think it
        will only be practical in larger production environments, at least
        for a number of years. There's nothing any more magical about
        using CAF than scratch-building (but I suspect most of us
        involved in that are using something with more metallic content
        than our fingernails! :) or any other techniques. I am very much
        looking forward to learning from those who already use some
        form of CAF in their creative efforts, whether it's for themselves or
        a commercially manufactured product, and for creating the parts
        directly or tooling like molds/jigs/bits/cutters/etc.


        - Potential CAF Techniques to Investigate for Z Scale

        As has been pointed out, Z scale requires a
        jeweler's/watchmaker's touch, unlike the larger scales. Since
        we want to replicate most of the details that can require a
        magnifying glass to even see at our scale, non-traditional
        railroad modeling techniques are needed. We've already
        mentioned that CNC milling machines and lathes are common
        CAF tools, but what is keyed into them and used to modify stock
        material may be just as interesting to investigate. A quick look at
        a typical Dremel Moto-Tool kit suggests all sorts of possibilities
        beyond the standard end and side cutters found in milling
        machines and lathes. Those are used to remove various
        amounts of stock material at a whack, of course, but I'm
        wondering whether finishing materials like wire brush,
        sandpaper and wet/dry emory cloth are or can be used in a
        spindle/chuck, not just in a rotational mode, but in a vertical
        surface-impacting mode (e.g., using the Z-axis stepper motor in
        a milling machine to repeatedly press the finishing material into
        the stock material surface). This could allow textures to be
        established in surfaces by incrementing the position of the
        finishing material by one or more minimum steps the CAF tool is
        capable of, in regular or randomized patterns (important for
        replicating prototype surfaces realistically). I have the same
        question about using needle-like or other very sharp implements
        that can be safely keyed in a spindle and that won't
        shatter/bend/snap on impact (but the smaller CNC machines
        can't generate much torque or spindle vertical speed, so that
        shouldn't be much of a problem). Another potential technique I
        would like to find out the feasibility of would be keying a single
        paintbrush bristle (is sable the most fine?) in a spindle and then
        having the bristle dipped in a paint/ink source and then dabbing
        it repeatedly on the stock surface to form lettering, graphics, etc.
        (not sure how the bristle should be cleaned between colors -
        dipped in solvent, wiped on an absorbent pad, etc.). Obviously,
        this depends on the resolution and repeatability accuracy of the
        CAF tools, which brings us to the next topic ...


        - Resolution and Repeatability Limits in CAF for Z Scale

        CAF tools have resolutions claimed to be from several
        ten-thousandths of an inch, down to microns. Repeatability (how
        close the tool can return to a starting position after the
        spindle/head has been moved some distance away from the
        starting position) is typically about two to ten times the claimed
        resolution. What resolutions/repeatability are needed for the
        various tasks associated with fabricating Z scale parts?


        - Additional CAF Technologies

        3-D lithography typically involves a moderate-power laser being
        pulsed down into the surface of a pool of a heat-sensitive
        polymer (it immediately hardens where and when heated), with
        the laser's horizontal position being under computer control.
        The object being created is "drawn" as a bitmap (like the dots on
        the screen of your computer or paper in a printer) by the laser,
        layer-by-layer, starting from the bottom. As the first layer is
        "drawn", it is supported by a grid sitting just below the surface of
        the polymer at the start, and the grid is lowered by the thickness
        of each layer as each layer is "drawn" on top of the previous
        layer. When the top layer has been "drawn", the object is lifted
        out of the pool and cleaned off. There have been other 3-D
        technologies which deposit layers of colored wax or plastic
        droplets that solidify/harden, again, from bottom-to-top (I was
        working with Texas Instruments on another project and got to
        see their original prototype). The objects created are usually
        meant to be further machined/finished and used as positive
        masters for creating molds via lost-wax or
        impression-displacement methods. I don't know what the cost
        of 3-D lithography using these or other techniques is now, but I
        do know that the processes were excruciatingly slow, the objects
        created were fairly fragile, and it was all pretty messy
        (translation: expensive) from a maintenance perspective (the
        polymer/wax/plastic tended to dry out or harden in the
        mechanisms).


        - CAF in the Z Scale Modeling Workflow

        I am curious how milling machines are used to create injection
        molds, but the molds could produce more detail than the milling
        machine's resolution. Is it because of additional finishing
        (sanding/grinding/polishing/texturing) done to the interior
        surfaces of the molds? Can anyone with experience in this area
        elucidate the rest of us?

        The issue of setup time, particularly positioning in a repeatable
        manner. The typical method for dealing with this, in my
        experience, is using templates and jigs, and I think the time
        required to create these is what Nelson was talking about.
        However, once again, these could become part of the definition
        of the product, and once the data files have been generated, they
        can be shared with everyone else so each member can fabricate
        the templates and jigs locally.


        - May Need to Start Marketplace to Facilitate Parts Exchange

        I fully support Nelson's suggestion that we could trade or sell
        parts, in addition to data files. I suppose we need to figure out
        how to create a marketplace to facilitate trading and sales, if it
        needs to advance beyond deals between any two parties. We
        may want to create a parts/products database in the Database
        area of the group, both to facilitate trades/sales, and to keep
        everyone abreast of what each of us is working on to avoid
        duplication of effort.


        - Fabricating and Operating Large Z Scale Stock for Typical
        Layouts

        There I was, being the Pollyanna of the Z track group, calling
        everyone to arms, to think outside the refrigerator box, and then I
        go and fall into the OldThink trap of downtalking Z scale models
        of oversized prototypes like the DD40AX (X? XA? Is there a
        historian in the house?!?) on our smaller layouts. Ironically,
        these large models are probably best run on modular layouts,
        since they tend to standardize on fairly large radius track curves,
        and I am working on a modular layout myself. As usual, I take
        my hat off to the wiser folks on the list, such as Rob Kluz.
        Thanks for keeping me referenced to ground!

        All the BeZt,
        Jim


        --- In z_scale@yahoogroups.com, "Lajos Thek" <olaj@d...>
        wrote:
        > To build an injection mold for a well detaled product you
        > need to use mill and lathe. The trick is knowing how to design
        > and make the necessary tooling. To design something in 3D is
        > the least expensive part of the process. To convert the program
        > to a working product requires many expensive steps.

        --- In z_scale@yahoogroups.com, "michael" <mptuason@y...>
        wrote:
        > What about 3D (Stereo) Lithography?

        --- In z_scale@yahoogroups.com, "kimvellore" <kim@b...> wrote:
        > Jim,
        > I don't want to bring your enthusiasm down but I feel what we
        > currently lack in building Z scale anything is either casting or
        > injection molding. Some level of detail can be obtained by
        > Photo etching, but none of the lathe and end mills can get to
        > the level of detail that casting or injection molding gets.

        --- In z_scale@yahoogroups.com, "themohican2003"
        <themohican2003@y...> wrote:
        > I myself am planning to use a combination of resin castings for
        > bodies and chemically etched metal detail parts like the end
        > frames, roof walks and hopper hatches.  I almost considered
        > making metal bodies from etched sheet metal, but I didn't care
        > to solder all those cars, plus I would still have to cast the frame
        > for mounting the coupler/truck assemblies.
        > Hoppers Away!!!
        > Allan Borg

        --- In z_scale@yahoogroups.com, ztrack@a... wrote:
        > Z is the perfect scale to operate such a large locomotive. HO
        > and above is impractical.  One of the benefits of Z scale is that
        > we can model large locomotives and cars with zero
        > compression. We can have completely prototypical curves that
        > can be broad enough to handle a 5 inch loco with no problem.
        > The only limitation is ones own space for a layout, but again,
        > that is where Z scale has it's advantages. Though we work
        > small, it is time to think big.
        > Rob Kluz

        --- In z_scale@yahoogroups.com, Nelson Snedeker <nel@b...>
        wrote:
        > Just purchasing the tooling to use with these machines is a
        > substantial investment and a lot of their use is used up making
        > the special tooling you need to make whatever projects you are
        > working on. Set up time, in my limited experience, is the same
        > or more for CNC.  Each piece is a labor of Love and if you wish
        > to change that to a labor for profit some of it or most of it, will
        > have to be subcontracted.  For instance Chassis makers,
        > could trade for etched parts, any excess, in turn, could be
        > traded for Wheels, Bells, etc.  Instead of money changing
        > hands, the various talents of the group could be distributed
        > throughout the group. Also, there could be a surplus of major
        > pieces made into kits to sell to members or any other
        > enthusiast.  And that, Gentlemen, is how Corporations get their
        > start.  :-)
        > Happy "Z" ing  Nel

        --- In z_scale@yahoogroups.com, "kimvellore" <kim@b...>
        wrote:
        > So in order of priority I would say Casting, Photo Etch, CNC
        > machining, decal making and painting. The CNC parts could
        > also be eventually cast. It is a great effort that you making for Z
        > scale community, but concentrating on CNC alone will not be
        > able to achieve what you are trying to do.
      • Lajos Thek
        ... Imagine a simple passenger car, a box with windows, some lines for doors, rows of rivets. To build the injection mold, you ll build a box around your
        Message 3 of 3 , Dec 3, 2003
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          --- In z_scale@yahoogroups.com, "jim_manley_alpha_six"
          <jim_manley@h...> wrote:
          > >
          > I am curious how milling machines are used to create injection
          > molds, but the molds could produce more detail than the milling
          > machine's resolution.

          Imagine a simple passenger car, a box with windows, some lines for
          doors, rows of rivets. To build the injection mold, you'll build a
          box around your imaginary project. Build each side individually,
          then assemble the tool. To get the windows, insert the exact window
          size blocks into the side pieces, leave out the thickness of the
          shell. The fine lines can be created with inserted "blades" barely
          sticking out. The rivets can be reproduced with rows of
          fine "countersinks". Additional details can be done by machined
          inserts and plugs pressed into the sides of "box". The extremely
          fine details are done by hand, but quality milling machines and
          lathes can produce surprisingly fine details. Obviously the CNC
          mill is the optimal tool to make the recesses for the inserts,
          also to "countersink" the rows of rivets...
          Lajos
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