Continuous vertical lines on shell



  • Hello,

    since a while (possibly since I've switched to a Duet 2 Wifi) I've been fighting with a weird print quality issue.
    What happens is that all my flat walls suffer from weird vertical lines, that are clearly visible under the right light and often also sensible when going over the wall with fingernails etc.
    It kinda looks similar to ringing, just that it happens everywhere and even on very long straight moves.

    I tried many things to solve this, but by now I'm out of ideas and wonder if it's maybe not a mechanical issue but rather something software wise.

    Some images of the issue:
    0_1563141914194_IMG_20190714_232020.jpg
    0_1563141964397_IMG_20190714_232031.jpg

    Please note, these vertical lines are all the same across that entire wall, the light just makes it look like they are only in some spots, it's a very regular pattern. They also appear on all walls, no matter the axis.

    That specific print has a layer height of .2mm, using 3 line wide shells with a .4mm nozzle and 15% triangle infill. The same issue also appears with smaller (.3mm) and larger (.6mm) nozzles the same way. Layer height does not affect it either.

    Here's what I tried so far:

    • Adjusted belt tension from very stiff to very loose, no changes

    • Replaced belts with high quality Gates belts from E3D, replaced all pulleys and idlers with matching ones from Gates

    • Stiffened up the whole frame of the printer, assuming it was some sort of ringing

    Here's some info about my printer:

    • Started out as a regular Creality CR-10 Mini

    • Got an original Titan aero extruder now

    • Steppers are all replaced with good quality 1.6° ones

    • The Duet is running firmware 2.02 atm

    Here's also my current config.g:
    0_1563142486364_config.g

    I really hope someone has a good idea as this really destroys the surface finish of otherwise pretty perfect parts...



  • @diamondback said in Continuous vertical lines on shell:

    Titan aero extruder

    Check the bearings.



  • @phaedrux said in Continuous vertical lines on shell:

    @diamondback said in Continuous vertical lines on shell:

    Titan aero extruder

    Check the bearings.

    Check as in check if the lid bearing is damaged?
    Printer is busy atm, but the switch to the Aero is rather recent, before I was running a regular Titan setup which had the same issues (mentioning this because the Aero upgrade kit comes with a new lid bearing which is in use atm)

    Or is there anything else about the bearing that could be wrong? I don't think I've overtightened anything with either the original Titan or the Aero upgrade, but is there an easy way to check?



  • @diamondback the drive gear bolt is easy to overtighten and damage the bearing. There's the one in the lid and the one in the frame. There's also the idler arm bearing.

    A regular pattern that shows on all axis would seem to me to be an extruder issue and the titan Aero is known to have some issues with bearings. First place I'd look anyway.

    Does changing the extrusion amount change the distance between ridges?



  • @diamondback said in Continuous vertical lines on shell:

    is there an easy way to check?

    You'd have to visually inspect the bearing at the very least. Black oil leaking out would be a tell tale sign.


  • administrators

    Here are some tests you can do:

    1. If you print a cube, do you get that pattern on both pairs of faces, or only one pair? If both faces then it's probably and extrusion issue. If one pair then it's an axis movement issue.

    2. If you change the layer height or the extrusion width (so that the extrusion rate per linear mm of the print changes), does the pitch of the vertical lines change? If yes then it's an extrusion issue, if no then it's an axis movement issue.



  • Thank you both a lot for your answers, since my Aero is a bit tricky to take apart I'll test print two cubes at .1 and .3mm layers first to further assure that it's an extrusion issue.



  • Ok so, results are in, the change in layer height made a massive difference, with .3 the issue is barely visible (probably frequency high enough for it to disappear?), while .1 shows it very clearly.
    It also shows on all walls of the cube, even though one axis seems to suffer a bit less (on both cubes), but's clearly visible on all walls.

    So other than Titan bearings, any other ideas I can try before taking the printer apart? Maybe something about micro stepping, interpolation etc? Bed leveling maybe? (I got a Z probe installed)


  • administrators

    You can try adjusting the extruder microstepping, but I suspect a problem with the extruder gears or hobbed shaft.



  • If the striations are vertically aligned doesn't that rule out the extruder? I mean wouldn't it be a remarkable coincidence to have a perimeter that was an exact multiple of the extruder microsteps or tooth pitch?

    Isn't it more likely axis speed modulations?



  • @Diamondback ,

    Is the pitch of the lines related to the belt tooth pitch?

    Do you have any toothed belts running tooth side inwards over smooth pulleys?



  • @nophead I have similiar problem and I have toothed belts running tooth side inwards over smooth pulleys. Do You think that it cause this problem?

    I had this problem also on the printer which has belts only on tooth pulleys.


  • administrators

    @nophead said in Continuous vertical lines on shell:

    If the striations are vertically aligned doesn't that rule out the extruder? I mean wouldn't it be a remarkable coincidence to have a perimeter that was an exact multiple of the extruder microsteps or tooth pitch?

    Isn't it more likely axis speed modulations?

    That's a good point. But if it's axis speed modulations, why does it change with layer height?



  • @nophead said in Continuous vertical lines on shell:

    @Diamondback ,

    Is the pitch of the lines related to the belt tooth pitch?

    Do you have any toothed belts running tooth side inwards over smooth pulleys?

    I'm not quite sure how I would relate the line pitch to the belt pitch, any tips?

    I do have a smooth idler facing the teeth on the Y-axis (which is also the axis that shows the issue more), I have the correct toothed idler around, attaching it just ended up being a pain so I left the stock (smooth) one in there.

    I wonder though why this wasn't an issue from the beginning when I got the printer, possibly softer teeth than my Gates belt now? Ie the teeth just being depressed enough that it didn't really matter?

    @dc42 said in Continuous vertical lines on shell:

    @nophead said in Continuous vertical lines on shell:

    If the striations are vertically aligned doesn't that rule out the extruder? I mean wouldn't it be a remarkable coincidence to have a perimeter that was an exact multiple of the extruder microsteps or tooth pitch?

    Isn't it more likely axis speed modulations?

    That's a good point. But if it's axis speed modulations, why does it change with layer height?

    Hm maybe something to do with some extruder jerk or whatever value leading to different speeds at higher flowrates? Pressure advance?



  • @diamondback said in Continuous vertical lines on shell:

    I'm not quite sure how I would relate the line pitch to the belt pitch, any tips?

    The belt pitch is likely 2mm. Is the distance between ridges also 2mm?



  • @phaedrux said in Continuous vertical lines on shell:

    @diamondback said in Continuous vertical lines on shell:

    I'm not quite sure how I would relate the line pitch to the belt pitch, any tips?

    The belt pitch is likely 2mm. Is the distance between ridges also 2mm?

    The pitch seems to be something like 1.2mm (averaged over 7 peaks), hard to measure...



  • I have measured mine and it was the same distance which You measured.



  • @diamondback How many teeth on your pulleys?

    If it isn't related to belt pitch then perhaps motor steps.



  • @nophead said in Continuous vertical lines on shell:

    @diamondback How many teeth on your pulleys?

    If it isn't related to belt pitch then perhaps motor steps.

    Both idler and pulley have 20 teeth on both axis.



  • I have found the solution. You need to use teeth idlers instead of flat.


 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.