This topic contains 21 replies, has 12 voices, and was last updated by Avatar delt0r 5 years, 8 months ago.

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  • #1328
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    AaronB
    Member

    We need some help drawing a new part for FoFu in a CAD program. Our current staff has very limited experience. Anyone interested in helping?

    #11617
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    DerekShannon
    Member

    Here’s an example of a preliminary drawing that I made in Sketchup. The idea is for a single press fit tungsten ring to replace the 100 (now 96, to have 16 [the number of cathode rods] as a divisor, fyi) tungsten pins, which continue to cause headaches.

    Instead of a continuous upper edge, however, Eric wants to add a zigzag of 96 evenly spaced points, each 90 degrees, to duplicate the pin functionality but with much easier assembly. So I’m working to improve my Autodesk skills so we can get quotes on that more complex design, and in the meantime have found this as the closest analogue. So folks don’t have to wonder what the design in those .ipt files looks like, a hole saw looks like this. Our right angle points are actually a bit simpler than these wavy sawteeth.

    Attached files

    #11618
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    zapkitty
    Member

    96 right angles on top of any given cylinder comes out like the attached… is this the general idea?

    Attached files

    #11619
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    DerekShannon
    Member

    A great Blessing of the High Voltage Kitteh upon Thee! ;-D

    #11620
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    DerekShannon
    Member

    Srslry, I told a machine shop “Picture Thou the T-Shirt of Charlie Brown…”

    #11621
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    zapkitty
    Member

    … then if I got this right…

    Attached files

    #11622
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    Milemaster
    Member

    Looking to this base ring design, I could not avoid thinking of continuing the 90 degrees groove up to the top of the anode. This provides a Guide or railway to the plasma sheat and could be used in many ways. If they rise vertically ok we will have a concentrated plasma in the points. Looking to images of a used anode, we can see the grooves that the discharge makes trying to get into the center hole.
    Now, we could make this vertical grooves slightly Helical, (Rifled) This will induce a circular motion to the plasma, similar to the effect of the coil and improving the filament formation allowing to manage the plasmoid size.

    #11623
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    Lerner
    Participant

    We did think about this, but the problem is that it can’t be adjusted. The coil can be changed with a twsit of the knob to cary more or less current, which changes the angular momentum conveyed.

    #11624

    Milemaster wrote:
    Now, we could make this vertical grooves slightly Helical, (Rifled) This will induce a circular motion to the plasma, similar to the effect of the coil and improving the filament formation allowing to manage the plasmoid size.

    The other potential problem with the helical geometry is someone has a patent on that approach.

    #11625
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    zapkitty
    Member

    So, if I have the right idea, then what is needed here?

    #11628
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    DerekShannon
    Member

    Hey, ZK! I actually thought the 3D files I received earlier today were from you for a while, so you certainly get full credit–But I am happy to say that I was able to make a drawing from a Rhino3D model that Chris Kuether kindly sent in.

    Now we’re waiting to hear back from a few shops with the ability to machine tungsten. The best so far would need to add radii of curvature of .004″ to a piece of 99.95% tungsten. Chris also added

    DMLS might be practical [Direct Metal Laser Sintering] .. fused from tungsten powder, just locally. Practically zero scrap.

    So we’re open to further suggestions for a place that can do DMLS with tungsten or otherwise has some W expertise (assume we’ve already checked out the top few Google hits). The earlier simple knife edge was quoted at just a few hundred, so it will be interesting to see how much 96 sawteeth adds to the cost.

    #11629
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    willit
    Participant

    i like mine with more color.

    Attached files

    #11630
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    Patientman
    Participant

    I apologize if this is a technical monkey wrench in your discussions and can be disregarded on the whole, if it make no sense at all.

    Do you expose the outer ring of electrodes in the reactor area?
    Why expose the entire face (360 degrees) of the electrode if only the surface facing inwards (180 degrees or less) conducts the energy needed?

    There maybe some benefits, although engineering a barrier and revising a whole reactor chamber is a problem…

    Just a question to ponder.

    #11631
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    willit
    Participant

    another thought on symmetry and fillament formation. limiting the places that fillament formation can take place can lead to stronger and well placed fillaments. along with formation, supplying a rail for fillament travel could help in keeping a fillament attatched to the cathode before rundown.
    one or two points to start a fillament using a small flyback transformer supplementary circuit to ensure a well formed streamer and then hit it with the big hammer cap bank………….symmetry.

    Attached files

    #11633
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    DerekShannon
    Member

    Good suggestions, Will & Patientman, I could definitely see them being addressed as part of future optimization. For example, if the walls of the vacuum chamber could be used as the cathode, then the X-ray energy capture materials could be brought that much closer; but perhaps there is such a thing as too close, if the flux of low energy neutrons from side reactions might then causes excessive damage (but the neutrons will still be too low energy to cause “activation,” so still no radioactive waste!).

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