Nozzle Design

Discussion in 'General' started by lachlan_M, Jun 2, 2014.

  1. lachlan_M

    lachlan_M Member

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    Hi everyone,

    I'm looking to redesign a nozzle for my V5 and I am hoping to make it out of a polymer or some non (electrically) conducting material with high temperature resistance (polyimide). I will obviously be CNC machining the nozzle from some form of stock material, and I was hoping to get some input. I want to know how long I could safely make the nozzle, I have seen some longer nozzles about. Also do you guys see any problem with using polyimide?

    For a bit of background, I am working on a thesis project and came up against a major issue due to the heater block and nozzle being metal. I obviously can't swap out the heater block with a non (electrically) conducting material, but I figure I can for the nozzle hence my plans. I'm hoping this is a good place to ask this question and who knows perhaps it will lead to design improvements for the current E3D nozzle.

    Cheers,
    Lachlan
     
  2. lachlan_M

    lachlan_M Member

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    Other materials I am looking in to: PTFE (although I am worried I may need temperatures that exceed its operating conditions ~260 degrees celsius) or machinable glass ceramics. PTFE is attractive due to its low coefficient of friction while machinable ceramics are attractive due to their high temperature range. Any other material suggestions?
     
  3. Creo

    Creo Member

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    Why do yo need an electrically insulative nozzle?
    Guess you might not be able to or want to divulge full info on what you are trying to accomplish but if you are still extruding a material that exhibits thermoplastic properties I see you having a thermal conductivity problem. Nozzles are made of materials that conduct heat well so it replenishes heat lost to the material by absorbing heat from the block to stay at a consistent, proper extrusion temp. No?

    If the material relies on freely moving valence electrons to transfer heat energy, it WILL also transfer electric energy.

    Maybe make your own....mica powder mixed in a high temperature machinable epoxy, pour into rod mold then machine after epoxy is set.
     
  4. lachlan_M

    lachlan_M Member

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    Yes sorry, I would prefer not to fully disclose my intentions at the moment, I realise this may seem unhelpful or selfish. Regardless I had been concerned with the loss of thermal conductivity but I also had the thought that a thermally insulative material would prevent heat loss through the material (to an extent) therefore the only heat in and out of the control volume considering the polymer melt in the nozzle is heat addition from the hot material in the heater block and heat subtraction as the filament meets the open air at which point it is promptly deposited.

    I will look into the mica powder, why do you suggest it though? Does it conduct heat in a manner that would not also conduct electricity?

    Cheers for taking an interest in the question though, I would love to be able to bounce ideas off people to get the best solution.
     
  5. Creo

    Creo Member

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    Yes, mica transfers heat by phonons, not electrons. Powder cause as far as I know it doesn't come in a form that would be usable as stock for machining. Diamond is even better but you'd have a hell of a time trying to machine it :lol: not to mention its cost :shock: .
     

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