Printing issue for subsequent layers- Bigbox Dual

Discussion in 'BigBox General Chat' started by University of Toronto, Jan 27, 2017.

  1. University of Toronto

    University of Toronto Well-Known Member

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    Hi

    I have the bigbox dual, and I am trying to print a tensile dogbone shaped sample using my own composite material. The first layer prints really well, but the subsequent layers print very strange with irregular deposition. I increased the multiplier speed, as wellas the nizzle temperature and bed much above the melting temperature. It looks like the z axis is not moving as quick because it looks like sometimes the nozzle is going across the layer it just built, without moving up to create a new layer. Hence its creating melted drag marks across the layer. Please see attached the image of the first (I broke the samples) layer and the subsequent layers.Please ignore the rectangular samples

    Thank you

    Best Regards

    Ali Anwer

    Univresity of Toronto IMG_2101.JPG
     
  2. GrodanB

    GrodanB Well-Known Member

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    Check your current to the z driver. They are connected in parallel.

    Have not had this issue on mine but have seen post about it. Should be possible to find on this forum.
     
  3. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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  4. University of Toronto

    University of Toronto Well-Known Member

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    Thank you so much. Could you please guide me to the thread where I could find the instructions on how to drop the voltage of the z axis?

    Thanks
     
  5. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Must have been editing while you were posting......
     
  6. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    You need to follow the instructions in the build manual about tuning the stepper drivers. Instead of setting the z axis at the recommended voltage (0.58 I think) try turning it down a bit. I think mine were at 0.45v in the end.
     
  7. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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  8. University of Toronto

    University of Toronto Well-Known Member

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    Hi Jason,
    Going to try it soon! I am going to do that as last resort. Previously the z motion speed was like 125mm/min (I reduced it, thinking it would help print my custom material). I put it back to 1000mm/min default. I am testing my PLA (to not waste my custom material). So far, it seems to be good! Lets see what happens!

    If not, I will reduce my voltage for z axis.

    Thanks
     
  9. University of Toronto

    University of Toronto Well-Known Member

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    20170210_194436.jpg still same issue after reducing voltage to 0.395v as well. see attached image for PLA. It was working ok, when I increased the z axis speed to 1000mm/min. but now it went back to same old problem, hence reduced the voltage
     
  10. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Hmm, so probably not voltage then. I'm not convinced that the z-axis speed will make a big difference as the movement is so small (what's your layer thickness?) but I've not changed the z feed rate on my machine.

    Were you able to confirm that the z-axis wasn't moving on layer change? Have you double-checked the extruder filament calibration?

    I'd maybe try printing something smaller but taller like a 20mm cube? That may show up z issues easier. You can check the actual height printed vs what is on the LCD or what you expect. I've had issues printing with some filament where I was getting rumbling as the nozzle passes over the infill on the first layer or so.

    Which slicer are you using?
     
  11. University of Toronto

    University of Toronto Well-Known Member

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    Hi Jason,

    I could try putting the tensile sample not flat, but rather vertical and see or any other square box for example. I could see that the zaxis is moving though, but I am just looking at the lead screw move a bit. Also, yes I checked the extruder filament calibration for the 100mm using the calibration 1 for my bigbox dual. Also, with such uneven surface, its quite hard to measure the height.

    Also, I realized one thing, the layer height that is displayed on the start of the print is 0.09 and increases by 0.1 for each other layer. My z axis offset is 1.2mm. Is this correct? Is this an issue?

    I am using simplify3d that I purchased with the printer.

    Thanks

    Best Regards
     
  12. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Hello again,

    There's another thread related to z-axis issues, worth a read too:

    https://forum.e3d-online.com/index.php?threads/z-axis-right-side-droops.2370/

    The LCD readings sound OK. The z-offset is the difference between the nozzle tip and the point at which the sensor is triggered. That then acts as the zero point for the print. Your S3D setting is probably to reduce the first layer to 90% of the layer height hence the 0.09mm. Each layer is then 0.1mm added.

    I'd not print your tensile sample upright, it's too thin to stay stable and will wobble about. You can use a raft to keep it attached to the bed but the quality will still suffer. Try a cube, they do tend to make identifying faults easier, worked for me.

    What nozzle size are you using? Maybe have a go with a 0.2 or 0.25mm layer with a 0.4mm nozzle.

    It looks like the prints are over extruding but you've checked the calibration. If it's not a z-axis problem, could it be that the filament diameter is out of tolerance. Check by measuring and confirm the diameter is set correctly in the S3D profile.
    You can reduce the extrusion multiplier on the first settings page, it's a powerful setting but dropping it to 0.95 or maybe 0.9 can do the trick with some filaments. At first I would leave the extrusion width on auto initially.
     
  13. University of Toronto

    University of Toronto Well-Known Member

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    HI Jason,

    Yes you are correct, I set my S3D settings to 90% of the layer height. Sure, I will go ahead and print the cubic samples of 2ommX20mmX20mm.

    I am currently using a 0.8mm nozzle, and I had set the extrusion width to 0.8, and the extrusion multiplier to 1.5. even after this multiplier I felt initially it was not extruding as much, hence manually changed the extrusion flow while printing to 200% on the LCD screen. I will check the PLA filament diameter. I am using the filament I bought from E3D online from Spoolworks.

    Thanks alot for this detailed suggestion, I will surely go ahead and try it!

    Thanks

    Best Regards
     
    #13 University of Toronto, Feb 12, 2017
    Last edited: Feb 12, 2017
  14. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    Wow I think we might have found the problem. On my S3D setup a 0.8mm nozzle (are you using a volcano system?) gives a line width of 0.96mm. Therefore, 0.8mm line width will reduce the material flow rate through the nozzle and you may get an effect where it looks to be under extruding. If you have set your multiplier to 1.5 and then also set your 'Tune' flow to 200% then you are putting three times the normal flow through the nozzle. This is something that Simplify doesn't take account for so will create your g-code based upon the line width of 0.8mm.

    Working on a 0.1mm layer height, a 0.8mm line width will give 0.08mm² per mm of travel. With the overrides of 1.5 and 200%, you will be pumping out 0.24mm² per mm which will have to go somewhere but can't because the nozzle tip is there. It will push outside of the nozzle in all directions and produce much thicker, rough and ridged layers.

    In S3D, the extrusion multiplier is really only used to fine tune prints. I've never used greater then 1.0 or less than 0.9. If you find you are needing to 'Tune' the flow while printing every time, then adjust the extrusion multiplier for that material. Worth saving a separate S3D profile for each material too and tweak them over time. I found my settings had drifted over a space of months as I tinkered with them and I went back to the one recommended here and my prints improved a lot.

    Hope this helps!

    If you're still having trouble, try posting in the Volcano section, you may get good recommendations there too.
     
  15. University of Toronto

    University of Toronto Well-Known Member

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    I think im using the direct drive bowden
     
  16. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    OK, so not a volcano nozzle. Quite a big nozzle that!

    Try printing with PLA at the standard 1.0 multiplier settings, should be better.
     
  17. University of Toronto

    University of Toronto Well-Known Member

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    The reason we want to use a larger diameter nozzle is because our ultimate objective is to use a custom composite filament with larger fiber %. We tried with 0.4, but the nozzle seems to clog after a print or two of a tensile sample. Hence we thought by having a 0.8mm, it might be better. We are just trying filament to conserve our custom material, hence we wanted to first fix this problem with pla rather that moving to our filament which is a bit more challenging to print.

    Sure, we will try today the PLA with standard 1.0 multiplier settings and tune flow of 100% and see how this goes. If it doesnt go very well, will go ahead and change the layer thickness to 0.4 or 0.5 with 0.8mm nozzle and see. Do you think 0.4 should be good with a 0.8mm nozzle?

    Thanks
     
  18. Jasons_BigBox

    Jasons_BigBox Well-Known Member

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    I've not used a bigger nozzle than 0.4mm but general thinking is that the layer can be up to about 60% of the nozzle diameter I think.

    Ah, so you're MAKING filament! Should be interesting, keeping a tight tolerance on the diameter seems to be the trick according to some manufacturers.
     
  19. University of Toronto

    University of Toronto Well-Known Member

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    Yes, I am making my own filament, but the PLA that I used in this forum is bought directly from the manufacturer.Even that is having some issues. i am going to try out the suggestion and and increase it to 0.4 the layer height now!

    Thanks
     

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