Volcano Nozzle Blocking Up After Base Layer

Discussion in 'Volcano' started by AaronGreen, Oct 28, 2017.

  1. AaronGreen

    AaronGreen Member

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    The nozzle is getting blocked after printing for only a few minutes into a test cube.

    I've tried printing at 210c, 220c, and 235c. I've only every had a blocked nozzle using the volcano. The typical E3D has been working consistently.

    Any ideas?
     

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  2. Syko_Symatic

    Syko_Symatic Well-Known Member

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    Do you have the PTFE in the heatsink? I had a similar issue with one of my V6 hot ends and it was due to me forgetting to put the PTFE back.
     
  3. Old_Tafr

    Old_Tafr Well-Known Member

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    You are saying that the nozzle is blocked, but other than filament not coming out of the nozzle (assuming you are using the right temperature for the filament? you are using ) there is no way to know what exactly is happening.

    Is this a V6? and what diameter is the filament (as I think the 3 mm filament V6 setup does not use a ptfe tube in the heat sink)

    It is possible that the fan isn't cooling the heat sink (maybe no heat sink compound on the heat break?) or the assembly of the V6? isn't correct? or the fan isn't the right type or the fan shroud isn't fitted correctly or isn't blowing onto the heat sink correctly, or the print cooling fan is not at the right height and is blowing on the nozzle and cooling it too much?

    If it is the V6 then it could be the assembly of the heat break + compound + heat sink + nozzle, or it isn't the correct length of ptfe tube (bent straight and with a slight countersink to allow the filament easy entry ..............etc. could be the problem.

    More info would help :)

    I have just changed to a Volcano and no problems with blocking.............. just getting a decent print with Edge !!!
     
  4. AaronGreen

    AaronGreen Member

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    Thanks for the info. I have a 1.75mm E3D Volcano, and it has the exact same problem as the $10 clone from China. It printed three test cubes just fine, and a nozzle fan halve, but blocked by the second nozzle fan half.

    I opened it up and simply found a wick of the filament stuck in the nozzle, while running it at 210c, which is the PLA temperature I've been using for a year, and have been printing for this set up.

    My fan just stopped working for some reason though. But I'm not sure what the story is about not using a heat sink fan with regards to filament not melting only a few millimetres away from the heater. And the DuetWiFi board I'm using is showing a consistent fluctuation of heat above the required PLA melting point. After all, it's already printed 4 small prints.

    If I pull the filament out, then gently push a new section of filament through it starts feeding just fine. When I start the print, it doesn't even make it through the base layer before clogging up again. I'll try and get the fan working again, but I'm out of ideas otherwise.
     
  5. AaronGreen

    AaronGreen Member

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    Yes. The PTFE tube runs from the Titan extruder all the way through the heatsink to the heat block screw. At that point, the screw is about 2mm in diameter, to allow the 1.75mm filament through. The place where the filament is stuck is in the middle to upper section of the nozzle. I don't understand how it doesn't melt being right next to a giant longitudinal heater running at 210c for PLA, and even up to 235c, just to see if it'll melt then. Still, nothing. It blocks every time I clean it out and try again. I've already printed 4 objects just fine, on different days.
     
  6. Old_Tafr

    Old_Tafr Well-Known Member

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    What puzzles me here is that I would imagine most people stop printing let the machine cool and then start printing from scratch again some other time. So the filament is cold and solid in the nozzle and heats and extrudes again for the next print.

    If the cooling fan for the heat-sink comes on at 40oC as the temp increases and stays on without interruption after the print until the temp drops to below 40oC then melted filament should never get to a point where it solidifies anywhere where it won't be melted again next time, e.g. won't melt in the heat-break.

    If you...

    A. have followed the V6 assembly to the letter (I know the Volcano instructions are a little vague, but essentially it's the same as the standard V6 as the longer nozzle thread {you are using the longer threaded Volcano nozzle?} makes up the length difference when using the vertically mounted Volcano Al block.

    B. Keep the heat-sink cooling on from 40oC going up / printing / cooling down to below 40oC

    C. have the cooling fan directed onto the heat-sink correctly

    Then it should just work.

    The only other possibility which sounds daft is that the filament is pulled upward at the end of the print, stretching it up inside the heat-break preventing the filament pushing down next time.

    Have you tried just heating the nozzle but not printing? For example when doing a calibration so you know that say 100mm of filament is being extruded, at this point some filament just drips or extrudes under the force of gravity?

    Do you see the filament drip out as you heat the nozzle, and could you try heating the nozzle and just pushing the filament by hand to see what happens?

    I know the nozzle is hot simply because filament stuck to it melts (and can then be easily removed) as I normally pre-heat the nozzle prior to printing, this allows me to use a brass bristle brush to clean the melted gunge off the nozzle before printing starts (wipe just does not do this sufficiently) if this is happening you know the nozzle is hot and pushing on the filament (if necessary by hand) should cause more filament to exit the nozzle.
     

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