Volcano and OOZE

Discussion in 'Volcano' started by R Design, Mar 29, 2016.

  1. R Design

    R Design Well-Known Member

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    Looking for strategies for combatting Ooze when traversing large gaps and using the Volcano. Don't like nasty useless blobs on landing, nor appreciate little deposits during travel (especially on outer perimeters).

    Am using Colorfabb XT which is, perhaps, a relatively oozy filament, with a Volcano 0.8mm nozzle.

    I set up a test with 3 * 1cm cubes placed at different places on the build plate, watched what happened when I varied various parameters on the fly (nozzle temperature, parts fan....) and then many others in Gcode (using Simplify 3d).

    So far my conclusions are:

    1) Nozzle temperature is the most powerful controller of ooze. At 240C Colorfabb XT oozes mildly, but does not look the nicest in prints. 250C upwards is a disaster. 245C is the barely bearable compromise;

    2) After that the best thing is to max out the XY travel speeds (and minimise time lost Z lifting);

    3) Increasing retraction (from 1.5mm) and increasing retraction speeds (from 75mm/s) didn't seem to help;

    4) Nor did S3d's "Coasting" feature which I thought might relieve pressure in the nozzle prior to take-off;

    Though inexperienced I am supposing that XT (gooey) and Volcano (large melt zone) is a reasonably nasty combination.

    Does anyone have any further suggestions?

    Addendum: since I'm using "only" a 0.8mm nozzle I could probably "go back" to a regular 0.8 (not volcano). But let's try to crack this.... 1mm Volcano beckons!
     
  2. dbeck002

    dbeck002 Member

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    Hi, I have a similar issue. I am running a volcano, I used a retraction setting of 7mm and an extra restart of -0.5mm. This is severe overkill, but I wanted to see at what point will the blobs dissappear . This combination of settings does work but it seems like there must be a more elegant solution to this. The Volcano hot zone is very long so that doesnt help, thats why I used a lot of retraction. Coast does help, bump it up to around 1-2 mm. Be careful though, if you run these settings you will end up under extruding if your parts are small since there will never really be any filament in the hotend because of all the retractions adding up the negative restart distances!!
     
  3. R Design

    R Design Well-Known Member

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    Hmmm... I also found Coast to be useful.

    Retraction is a mystery to me. And, despite asking around, nobody has been able to explain how to go about calibrating it. What tests to do, what settings to try and what results to look for.

    I've heard it said that retraction settings (the distance, in particular) may be based in part on the internal geometry of the nozzle. Perhaps E3d have something to say about that for the Volcano?

    I've also heard it said that the retraction speed should not be "too high" and is dependent upon the gooeyness of the melt, of the specific plastic.

    I tried increasing the distance incrementally from the default value in the BB profile but it seemed to make no difference?

    Perhaps that's because the speed was in the wrong zone?

    Would anyone else like to chip in to this thread?
     
  4. mike01hu

    mike01hu Well-Known Member

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    Why not message Richard Horne as he uses the Volcano a lot.
     
  5. Spoon Unit

    Spoon Unit Well-Known Member

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    @R Design have you tried using an Ooze shield? If you're printing in a single material, this could be the ticked for the volcano nozzles. One thing you can't alter (readily) is gravity. The pull of that on the extra content in the melt zone is going to result in a physical effect. If you retract too far back you're going to have deformed filament above the nozzle entry which could jam. Ram purging is not the solution for a simple move, and you still have the challenge of moving back into place after the purge.

    Perhaps something to play with is z-lift. So you think about you're model. You think of the longest move step. You have a feeling this will ooze a certain amount. So you lift a little more than that amount. If your initial retraction is set right, you should be in the air after the z-lift without a string connected to the model. Now you move. Then when you restart, you want to be inside the edge of the mode. So you want to have a least two shells and be printing those shells inner-to-outer. Even if you deposit a little extra material, it should matter to much, but as you're on the inside shell anyway, you could compensate with a negative extra restart distance.

    Hopefully there's a few ideas there to play with anyway.
     
  6. Alex9779

    Alex9779 Moderator
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    Oh snap all my plans are busted!!! :rolleyes:

    This all can help but IMHO there would be much easier solutions if there were features for them in the slicers.

    For example to fight the little gap on the outer perimeter, the Z scar, could probably minimized if you'd have a setting to move the head a little over the old path before moving to the next line. "Wiping" is going in that directions but when wiping you do not extrude and and wipe movement is made with a different speed so the filament deposition is different. Only less than a millimeter would be enough IMHO...

    For oozing I am thinking of why not just move the head over some infill? Why is the "wiping" just going over a already laid line and not towards the infill? The problem is that the path the head goes when wiping is that there is material under the nozzle which prevents the wipe effect of letting the filament "stream" out of the nozzle. Would make much more sense to move over no material so no force will prevent that streaming, but then you will get strings. So the best solution would be to just move over some infilled areas, there the filament can stream out of the nozzle while being wiped be the next infill line. If you do that for some millimeters crossing several infill lines the wipe effect would be much improved.

    There are several other problems which could be countered with special movement options but that has to be made in the slicer.
    Slic3er could be an alternative and is open for expansion, but that is out of my reach at the moment and I do not like Slic3r very much. It is slow, is crashes often on my machines, tried Windows and Linux and Mac. I hope we will see a new release of S3D soon with nice new features...
     
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  7. Alex9779

    Alex9779 Moderator
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    And for the "coasting" setting, this is also nice but in total you have to combine this with some extra restart distance. Because when coasting you reduce the pressure in the nozzle, the extra restart distance you need to build it up again for normal printing. In total this can lead to underextrusion at a certain stage of the part.
    A setting to define the "ooze amount over time" would be much easier to configure. The calculations could be done by the slicer then.
     
  8. R Design

    R Design Well-Known Member

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    @Spoon Unit true an ooze shield could solve a lot of the symptoms. I'd consider it as a last resort.

    Don't you think that it's pressure (expanding melting filament) that causes the blob to appear on the nozzle, rather than gravity? That's why reducing the printing temperature can be quite effective (however a good reason not to go to the bottom of the range - apart from interlayer bonding - is that when the volcano starts printing it tends to overwhelm the heater/PID and the temperature always drops a bit).

    I successfully used Z-lift to stop little blobs of ooze falling where the nozzle is travelling over the part, only to discover that that made things MUCH worse at the destination: a much bigger blob of ooze would arrive at the perimeter where printing was due to restart and that can get messy. So often better no z-lift.

    Thus far "extra restart distance" has my vote as the "setting most likely to cause artifacts" (aka HOLES!) elsewhere in the part.

    @Alex9779 Love your various slicer strategies: worth creating forum entries on the S3d site in the suggestions thread. Time for their annual update?

    Although I haven't had much luck with extra-restart, understand it may have some use. However don't see that one needs to use it BECAUSE of coasting. Rather, because coasting has not worked well enough.
     
  9. Alex9779

    Alex9779 Moderator
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    That forum is messed up with suggestions for "atomic" problems in most cases... There are very few suggestions which will provide solutions for general problems.

    I hope they won't go the "SolidWorks" path, that is "more features and again MORE FEATURES" and drop the basics.
    I still hate it that "Only retract when crossing open spaces" does not cover the path from the skirt to the part itself, no retractions happens. And there are other situations where the path is just NOT what you expect from the settings, mostly related to not retracting or retracting or doing strange moves over parts.
     
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  10. NinjaLars

    NinjaLars Active Member

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    Anything new on this?
    All the pre-orders are getting the Volcano so I hope we can find some good settings for this issue.

    Fire away!
     
  11. Old_Tafr

    Old_Tafr Well-Known Member

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    Original Kickstarter Dual BB, unchanged firmware which works really well with ABS and PLA.

    Recently changed to Volcano on left hand extruder.

    The Volcano assembly with the heater wires emerging at the top of the Al block (emerging horizontally and pressed up against the bottom of the fan body) means that the bottom of the heater protrudes well below the Al block, by about 3 or 4 mm, level with the bottom of the flats on the hex head of the nozzle.

    This protrusion is anticipated by E3D as the Volcano sock has two holes in it, one for the nozzle and the other for the heater.

    Is it possible that radiant heat from the heater direct onto the nozzle causes local heating and therefore (more) ooze and that as the bottom of the heater is only the distance of the tapered part of the nozzle above the print, about 2mm that this also causes melting of already deposited filament?

    I have checked a spare heater and it is the same length as the heater I have fitted in my Volcano. (By moving the fan another mm up I may be able to push the heater back up a little. )

    I have been trying Volcano and Edge filament with an 0.8 mm nozzle as suggested by E3D ... (extrusion multiplier 0.9)

    "Broadly speaking, printing with Volcano is pretty easy. You just need to ensure that you've setup your slicer to use the correct nozzle diameter, and set a larger layer height.

    We would recommend starting out with the default 0.80mm nozzle, with 0.60mm layer heights. This makes for objects that are extremely strong, print quickly, and still look great. We have found that Slic3r http://slic3r.org/ seems to cope better with the creation of these large extrusion widths than other slicers."

    My general experience is that I have had to reduce the temp from the suggested 240 to 235 but keeping the first layer bed temp at 85 (less than 85 and the print lifts) even with 230 the print looks too melted and short distances are worse than long travel which in general prints ok without ooze or blobs, but has a melted looking appearance. On short distances say 10 to 20 mm I think that melted filament on the exterior of the nozzle (made worse by this melted filament running up between the nozzle and the sock) then sticks to the layer being printed causing the nozzle to drag partially cooled filament causing a rough rocky looking top layer.

    I have not tried various wipe and anti ooze settings in slic3r, but as a relatively inexperienced 3D printer I do find slic3r somewhat unpredictable e.g. using the simple settings I added a raft, previous runs had the print cooling fans off all the time, adding the raft (unexpectedly) brought the print cooling fans on at the first layer on top of the raft (with no warning) ruining the print. I had to go to expert mode to turn the fans off.

    I will try and move the heater up within the block, possibly by 1mm or so maybe 2 mm at most but I do think that compared to the conventional V6 design where the heater is horizontal the Volcano design may well contribute to ooze by overheating the nozzle and top layer of the print. A shorter heater and maybe a blind hole for the heater (danger of pressure and explosion though) would improve the design. A longer block would help keep the heater out of the way but would bend the heatbreak too much.
     
  12. Old_Tafr

    Old_Tafr Well-Known Member

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    Rather than show pictures of the printer itself, it is easier to see the relationship between the Al block, heat sink and heater in a mockup.

    The first picture shows the Volcano Al block with its cutout for the heater wires and the heater itself, so shows that the heater is much longer than the block.

    The second picture shows an assembled Volcano showing how the lowest fin of the heat sink presses on the heater wires preventing you moving the heater higher up in the Al block.

    The third picture shows the assembly with the sock fitted. Admittedly any heat radiation effect from the heater to the nozzle will probably be reduced by fitting the sock.

    Another aspect is that to heat the Al block the heater needs to be at a much higher temperature, this therefore means that the base of the heater at say 300oC is only two or 3 mm from the print, a bit like running a blow torch over the print and needing other parameters changed to compensate.

    One minor problem here was that the heater was too small in diameter (a subject of some old posts, yet this heater was obtained about six months ago) , or the hole in the Al block too big to be able to tighten the heater in place. My actual assembly in use is ok, this was just a mock-up to more easily show how there is no way to prevent the heater protruding 3 mm or so out of the Al block.
     

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    #12 Old_Tafr, Nov 6, 2017
    Last edited: Nov 8, 2017

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