This topic contains 21 replies, has 12 voices, and was last updated by Avatar delt0r 5 years, 6 months ago.

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  • #11634
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    willit
    Participant

    it just seems to me that filament are what you’re after. if my research is correct the first dpf machines used coaxial tubes with both the pins and blade configuration. if this is true it doesn’t make sense that you would have 96 pins all trying to grab a streamer and then distribute evenly to 16 anodes. plasma does what you make it do not what you want it to.

    also: when dc tig welding using tungsten for my electrode, I use 2% thoriated tungsten. it seems to have a more stable
    arc with the thorium and it starts easier also. i use green 0% thoriated for aluminum and run ac with a high frequency stabilizer during welding. this is what brought me the thought of stabilizing the arc or providing a light streamer to each of the rods which would pre initiate a pathway for each anode. you could even make sure that each streamer was present before firing the shot.

    is the inner ring seperate from the anode base plate or integral?

    #11636
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    Henning
    Participant

    As you’re asking on Twitter you’re looking for tungsten manufacturers. Most possibly you’ve already found this one, but nevertheless I’m posting it here: “China Tungsten”

    For their pure tungsten portfolio look at: http://www.tungsten.com.cn/

    Maybe a crucible comes close: http://www.tungsten.com.cn/tungsten-crucible.html

    As they’re not offering exactly what you want, ask them directly: sales@chinatungsten.com

    They’re also offering a design service (might be okay for pure tungsten too): http://www.chinatungsten.com/designing_carbides_alloys.htm

    #11637
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    DerekShannon
    Member

    Thanks, Henning, I did shoot them a request for a quote.

    ;-D

    #12903
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    meemoe_uk
    Member

    Have you tried out copper versions of this single jagged cylinder cathode yet?

    I suspect the arcs would unsportingly favour some points to arc from much more than others.

    #12911
    Avatar
    Henning
    Participant

    meemoe_uk2 wrote: Have you tried out copper versions of this single jagged cylinder cathode yet?

    I suspect the arcs would unsportingly favour some points to arc from much more than others.

    If you mean a single cathode base made out of copper including the sawtooth, but not including the cathode rods: Yes this has been tried. The current configuration, as far as I know, is a tungsten base including the sawtooth, but with copper cathode rods being screwed on.

    The problem, as far as I understand Eric, is the impurity induced be the small gap that happens when elements are screwed together, or actually the increased resistance. That’s why they’re looking now into a 3D-manufactured tungsten version of the whole cathode, as it’s hard to machine.

    Oh yes, and it needs to be tungsten, otherwise the sawtooth will evaporate away too quickly. Copper has been tried here before.

    Small giveaway: I’ve redesinged the DPF so that this gap between cathode base and cathode rods isn’t an obstacle anymore, in a way that filaments do not cross the cathode base anymore. Let’s see how Eric likes it.

    #12920
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    vansig
    Member

    asymmetric_implosion 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.

    existence of a patent was never and should never be an impediment to research.

    #12923
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    delt0r
    Member

    You do realize that they have a patent on some aspects as well. They can’t cry foul about patents if you have them too.

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