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Posted · circular shapes not closed

slicing a circular shape I noted a gap in the circlee vertical developing ... here is the print of a previous version of the same object.

Is there anything I can do to solve this problem?

image.gif.8a15dc71e953dcebe4c3b7fddbf063a6.gifIMG_20250113.thumb.gif.3b641be7eb85f79e1b1f34c5e267ed70.gif

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    Posted · circular shapes not closed

    The problem looks like it's underextruding significantly at the Z seam (where it starts/ends printing a part of a layer).

     

    If you could share a Cura project file (.3mf, get it set up then go to File > Save Project) of your print that will contain your print settings so we can see if there's anything wrong with the print settings and suggest a fix.

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    Posted · circular shapes not closed

    CFFFP_presa2.3mfI have an Hamlet 3D printer and printing ABS with the nozzle at 230°C and the bed at 103°C in a closed cabinet. The room climate is between +5 and 10°C.

    There are "intro" and "post" gcode statemets suggested by the vendor. The temperatures are set in the printer menu and can't be superseded by the gcode setting.

    Thank you

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    Posted · circular shapes not closed
    8 hours ago, frokal1 said:

    There are "intro" and "post" gcode statemets suggested by the vendor.

    I can see why you'd need ones suggested by the manufacturer... comparing the gcode commands to the RepRap gcode reference (which covers most gcode flavours since they're descendants of that) it doesn't seem to match any flavour. So it's hard for me to tell whether they're affecting it at all.

     

    8 hours ago, frokal1 said:

    printing ABS with the nozzle at 230°C and the bed at 103°C

    I haven't printed much ABS (way too much hassle for not enough reward) but when I did I ran it at 250°. Could that explain it? I would guess probably not... I could understand if it was making it a little reluctant to start flowing at the start of a layer, but the non-retract moves between lines should be quick enough to not interrupt the flow.

     

    So with that covered, I'll go over my checklist of "settings I'd expect could cause/help this":

    • Experimental > Enable Coasting  Nope, that's turned off.
    • Travel > Retract at Layer Change That's also off.
    • Cooling > Fan Speed:  Often with ABS you print without the fan on, since it can cause the print to warp depending on the cooling speed. Try disabling print cooling.
    • Material > Printing Temperature:  As I mentioned above, I've never printed ABS that cold. Try setting it to 250° and see if that helps.
    • Material > Flow  That's at 100%. If the rest of it was underextruded I'd suggest increasing it but other than the Z seam it looks fine.
    • Quality > Layer Height  Assuming you're using a "standard" 0.4mm nozzle, 0.1mm is a little lower than you'd often go (I usually don't go lower than 0.12mm, but I have done test prints at 0.08mm which were alright). Might be worth trying it at something more average like 0.2mm just to see if the increased flow helps.
    • Quality > Line Width Perfectly acceptable there
    • Walls > Minimum Wall Line Width  Not that you're printing narrower lines to begin with by the looks of it, but it's on my checklist. Still, 0.34mm is actually sort of conservative (general guideline for line width is 60-150% of nozzle diameter, so I have it set to 0.24mm).
    • Walls > Outer Wall Wipe Distance  This setting is designed to help close Z seams, but not for gaps this big. Depending on your extruder though, if it's a bit slow to get going, it could be a bit slow to stop, in which case this would help. Test with it at 1mm or something to see if it helps close the seam at all.
    • Material > Gradual Flow enabled  This is designed to help Bowden extruders by gradually changing the flow rate instead of just changing it instantly. I have a direct drive extruder so I don't need it but by the looks of your retraction settings you have a Bowden extruder so try turning this on.
    • Speed > Wall Speed: Nope, you're not trying to go an insane speed before it would set.
    • Speed > Enable Acceleration Control: 👀 It's something I'm always suspicious of these days because many manufacturers are in a pissing contest to see who can print a Benchy the fastest... so I'll just turn this on and look inside.
    • Speed > Enable Acceleration Control > Print Acceleration:  Your printer is set to 3000mm/s² (which is unusually quick for a Bowden extruder, unless it's not what your printer can do and inherited from another profile or a default). If it's zooming off before the filament is set it'll just drag it behind the nozzle instead of staying in place (my printer has pulled PLA at 4000mm/s² enough to warp the print, so I limited it in the firmware to 1000mm/s²). It also means it's even harder to control the flow rate properly on a Bowden extruder. Try turning this down to 500mm/s².
    • Speed > Enable Acceleration Control > Travel Acceleration:  That's set to 5000mm/s². It's entirely possible that's fast enough to drag a bit of filament when it travels between lines. Try turning it down to 1000mm/s².

    Hopefully some combination of those changes might be able to help you. Definitely change the ones I put a  on, see if that helps, and if that isn't enough, try the  ones one at a time (not like your print uses a ton of filament) and see what effect each one has. You might need to combine some of them, but hopefully some of those might do something.

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    Posted · circular shapes not closed

    Looking at the printer I see that in the circle is walked clockwise and counterclockwise stopping the travel in the same point layer by layer and feel a blow at each stop. It can be really the 5000 mm/s2 acceleration, but changing this parameter slower the travel? I try and tell you

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    Posted · circular shapes not closed

    That reminds me. I forgot to check the jerk values!

    image.thumb.png.d0a911c692a5b4f886dc4e7b1dd433bb.png

    That's a fairly average value but I usually run it at 8mm/s out of due paranoia. Jerk is how much the speed is allowed to change instantly at corners (since it can't slow all the way down, then change direction at the corner and accelerate away because that would leave a blob in the corner). If you're getting a blow where one bit stops it and changes direction to travel to the next bit, jerk is your primary candidate.

     

    Acceleration will still affect this: say you're turning at a traffic light and you think it might go red so you floor it, then slam on the brakes in order to make the turn, then floor it on the way out because you're in a hurry. You're going to feel the g-forces with the rapid deceleration and acceleration. Now say you slow down gradually as you come towards the light, turn at the exact same speed as before, but just accelerate normally on the way out. That's going to be a smooth ride that you're not really going to feel.

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