Having a hard time solving ringing/ghosting?

  • @phaedrux

    Its a whole lot better. So I am still having an issue with the back right corner, if view from the front of my printer, of the cube. it looks bunched up.

    So watching the print head it just very momentarily pauses during making the brim each time the nozzle passes the front left corner.

    The front left corner of the brim is raised up as well.
    0_1554613968022_duet2 .jpg

  • there are some ways to try and combat that. filament is oozing out of the hotend at those small pauses.
    Cura has a feature called coasting to try and combat that.

    However Duet implements an even more advanced feature called pressure advance
    there is a whole thread about configuring that.

  • @veti Thank you for that I will look into that.

    I will say this I was thinking about why it was pausing on that corner and realized at that corner is where it advanced to the next layer. I had retractions enabled. I thought maybe that is what was causing it so I turned retractions off. It has for sure improved.

    That said it is still having issues on the corners where the the letters are not in.

    0_1554617912624_duet2 .jpg

  • Running without retractions isn't really a great idea once you start printing something more complex than a cube. You'll end up with a lot of stringing and under runs at the start of a line after a travel because the filament will ooze out.

    In addition to pressure advance you should increase your Z axis speeds and acceleration a bit to make the pause at layer change quicker. Same for the extruder speed.

    Right now you have M203 Z250 E750 and M201 Z100 try increasing these to M203 Z600 E6000 and M201 Z300. If it behaves badly, back it off a tad.

    Also, how fast are you retracting in the slicer? Your config was limited it to 12.5mm/s which is very slow. 35-50mm/s would be more reasonable.

  • @phaedrux

    You knowni didnt even think about that. Thats fantastic. Hate being a noob. Anyway im done for the evening now its almost 3am here. I make suggested changes and report back tomorrow.

    I agree with wanting retractions to be turned on. But i was on the right track at least i was trying to speed up that layer change. I gotta get used to knowing that i can go in and say go faster.

    Thank you again!

  • administrators

    You should also look at pressure advance (M572) and dynamic acceleration control (M593). But start with retraction.

  • @phaedrux

    I did the pressure advance test code print.


    I made the suggested changes as well. Didnt behave badly at all. I was thinking I would bump them up a bit more. Retract speed is at 50mm/s.

    Im not sure what I should set my PA to though. not sure how to interpret that print.

  • What kind if printer is it? What kind if extruder? Is it using a bowden tube? If so, how long?

    A good value to start with on a direct drive extruder is 0.05.

  • @phaedrux

    Its an ender 3. Bowden extruder and the tube is right at 250mm long. I set it at .1

    I've discovered why my corners look better on the layers that include letters. The layer change when the printer moves the nozzle up happens in a different spot.

  • 0.1 sounds about right for that setup. Some pressure advance is better than no pressure advance.

  • @phaedrux

    So i discovered something else. The babystep buttons for the z axis if i put a .2mm offset the corners look alot better but the bottom layer on the buildplate looks like total crap.

    Makes me think it may be an issue withnover extrusion. But ive double check my value there and its pushing out exactly a 100mm

  • If you've already leveled the bed as best as you can, and you have a z probe, you may want to consider mesh grid compensation to help with the first layer.


  • @phaedrux Yip I am already using the mesh grid.

  • I wonder if it's your choice of layer height. I think the ender 3 z axis has a limited range of full step positions. I think it's steps of 0.04mm.

    Try a Google search for ender 3 magic layer height.

  • @Phaedrux
    yip you are correct it is .04mm. I read it as as long as your layer height is a factor of 4 then your good. I did just discover there is a setting in cura to randomize the start point of each layer. The setting is called Z seam alignment. I think it is going to solve my issue.

  • The z seam alignment option will need to be tailored to the model you're printing. Sometimes it can be hidden in corners, sometimes it's best to align it manually to the back side of the model. Sometimes you want the shortest travel to prevent stringing like with PETG. Randomized can be good for some things but it can leave little pick marks and bumps randomly over the surface which isn't always preferred.

  • @phaedrux

    Yip I have experience that. Printed a couple cubes to see what different settings would do.

    So changed jerk on the Z axis. Also upped accelerations a bit. The seem is starting to look good. I think I will be satisfied with this and move on to a bench test model and see how it performs and tune some more based on a for difficult print.

    I got a picture of the issue with brim. The nozzle slows down while printing the brim in this one corner. Once it is done with the brim it no longer slows down in that corner. 0_1554693678511_IMG_2453.jpg

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