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Wobbly Vertical Walls On My 3D Prints


TheBrodz

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Posted (edited) · Wobbly Vertical Walls On My 3D Prints

Hello,

I have just recnely bough a new 3d printer (A kobra Neo) and have been getting very bad prints ever since set up. The walls on my 3d prints are wonky and not straigt which gives very bad layers. Example shown below. I have tried many things such as

-Tried all different temps of bed and nozzle (190 - 220 C)

-Tested Belts

-Formatted SD card

-Adjusted eccentric nuts on bed, z and hotend

-Checked for anything wobbly

-Tried a new z screw and z axis compactor

-Loads and loads of test prints

-Messaged anycubic support an they dont really know either.

Any Ideas?

 

 

20221129_180721.jpg

20221129_180751.jpg

Edited by TheBrodz
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    Posted · Wobbly Vertical Walls On My 3D Prints

    When prints come out skewed it's (almost always) because the X Y and Z axes aren't perpendicular to each other.  If you look at the printer straight on from the front the X beam should be exactly 90° to the Z uprights.  Looking from either side, the beam that the Y travels on must be at exactly 90° to the Z uprights and the two Z uprights must be parallel to each other.  Looking straight down from the top - the Y beam must be at exactly 90° to the X beam.

     

    I've only seen pictures of your printer so I don't know for sure, but my Ender is screwed together.  Using a carpenter square and a metal straight edge - loosening the screws just enough to be able to rotate the Y beam into the correct alignment should get you a lot closer to exactly square prints (all faces of a cube at 90° to each other).

     

    This is what I do to "calibrate" my frame.  I check it every couple of months just to be sure.

     

    The printer should rest on a "substantial" very flat surface.  It should not dance when it is printing.

    • The Z uprights must be parallel top to bottom, and their front faces must be planar, and the uprights must be at 90° to the horizontal feet they mount to.  You can use pieces of paper on one side or the other as shims if required.
    • The Y-to-X adjustment is made by loosening the screws that come up from the bottom to hold the Y trolley beam in place.  That will allow the Y beam to rotate about the Z.
    • The Y-to-Z adjustment is made by loosening the screws that come in from the left and right sides.  That allows the "cross-beam-to-Y-beam" assembly to rotate about the X.
    • The X beam is a pain.  On my printer the screws are hidden by the left Z upright.  I drilled a hole in the upright so I can access at least the inboard screw head.  With that one just snug and the outboard screw tight, and the trolley wheels on the right end loose, I can move the right end of the X beam up and down (rotate about the Y) until it is at 90° to the Z uprights.  Then I snug down that inboard screw and adjust the right trolley wheels (and sometimes the mounting plate has to be moved a bit to align the fixed wheels to the track).  Without drilling the hole I had to pull the X beam assembly up off the top of the machine to loosen or tighten those screws.

    My printer came as a partial kit and assembling it caused me to come up with this saying:

    "Do not assume that just because parts of the printer were assembled by the factory - that they were assembled correctly.".

    It is very rare to have to calibrate the X, Y, or Z steppers.  When you print a cylinder though, it should be round.

    On these inexpensive printers it is always best (usually necessary) to calibrate the E steps/mm.

    No matter where in the Z the X beam is located, the threaded Z rod should always be parallel to the Z upright.  If the angle is different when Z=0 to when Z is at max-height then you might have to shim the Z motor mounting bracket.  If that angle does vary by position then you can get Z binding when near Z=0.

     

    There.  That should keep you out of trouble for a couple of hours.

     

     

     

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Hello,

    Thankyou for your reply

    I have checked all the axis and they are pretty straight (at least straight enough to be getting a lot better prints lol)

    The wiggly walls are happening on both the x and the y.

    Any more suggestions? Really confused as to what it could be.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    I think they use titanium oxide as the colorant in white filament.  That may make it touchier about print temperature as the flow rate through the nozzle can vary and cause characteristic ridges.  One layer looks inset and the next looks bulged out.

    I print white at 200, most others at 205-210, and silky PLA at 215 (because of their poor layer adhesion).

    If your prints are nice and squared up I'd go back to a temperature check.  If you are happy with the mechanicals then it's likely settings.  If you slice a cube and look at the gcode you'll see that every layer is identical other than skins or skirt.

     

    Another thing you can try is to print a cylinder.  The constant direction changes may tell you something.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Thanks for the reply

    I have PLA plus so tend to print a bit higher but from testing, the temp doesn't make much difference.

    Also i am getting a wierd bulge on the bottom few layers. It isn't elephants foot as it is for around 2 ml and then goes normal.

    Also, i have calibrated e steps and is extruding perfectly.

    Also, when i print a calibration cube it is 20/20.1 on all dimensions.

    I printed a 20mm cyclinder and measures 19.7/19.8.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Those are good dimensional numbers.

    The bulge on the bottom could be related to your Z system.  That is a characteristic of Z binding down low.  Another thing that can cause it is Z-hops and the right end of the X beam doesn't react for some reason.  It sounds like you've addressed those things though.

    Have you tried a different color filament?  I always found white to be the hardest to dial in.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    I ahve tried different colour filaments (balck and grey) and they do hide the layer inconsistencies a little bit but they are still noticable and really want to get rid of the issue instead of hiding it.

    Z-binding could be the prom=blem but i cant see anything wrong with the z and seems fine when printing.

    Any more suggestions?

    Thanks

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    Posted · Wobbly Vertical Walls On My 3D Prints

    If the speeds change by feature (60 print, 35 outer wall, 75 skins, 100 infill...that sort of thing) then the pressure constantly changes in the nozzle and consequently the line width changes.  That doesn't usually last all the way around a part though.

    If you'll post a project file ("File | Save Project") using your normal settings I'll take a look.

     

    I had what appears to be the same problem but for me it was with white only.  I started printing it cooler but that was about the same time I did a full PM on the printer so unfortunately I really don't know which fixed the problem.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Here is the project file. Its using Anycubic's recommended profile and settings. Not sure if it will chsnge anything but worth a try. Thanks for your help.

    PrinerProblems.3mf

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    Posted · Wobbly Vertical Walls On My 3D Prints

    You printer is pretty much a clone of an Ender 3.  I used your base setup in the 3mf and made some changes.  Looking at your startup and ending gcode I thought they could use some touching up so I changed those.

     

    When you open the attached 3mf file you will get a dialog asking if you want to update your printer and profile.  Change both options to "Create New".  That way your current profiles won't be over-written.

     

    These are my basic settings.  Take a look at what I've done because you know your printer best.  I did drop the printing temperature to 205° and change some speeds, the accel and jerk.

     

     

     

     

    GV Print Calibration Cube.3mf

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Hello,

    Thanks for that!

    Unfortunately that hasn't done anything. The print has rough sides still. It has 3 major bumps up its side - one at the bottom, middle and top. Still got the bottom few mm sticking out. Anything else that could be the culprit?

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Post the problem gcode.  I've got a little PLA left on one spool that I can throw at it.  If it prints well on my Ender then it's definitely something going on with your printer.

    I do have something in mind but it costs a few dollars and requires some modification of the bed wiring.  Better to make sure of where the problem is before blindly throwing money at it.

     

    One thing you can try (and this goes along with the alteration mentioned above) is to open that gcode file and search for "LAYER:1" and insert a M140 S0 line right there.  That will turn the bed off for the remainder of the print.  It isn't something you would do as a matter of course but if the electric current flow to the bed through the mainboard is interfering with the hot end current flow then the print may get better as it goes up.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Hello

    Here is the gcode. I will prbably try and get a replacement from anycubic before i modify it becasue as soon as i alter the printer i cant get a replacement.

    CFFFP_GV Print Calibration Cube.gcode

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    Posted · Wobbly Vertical Walls On My 3D Prints

    Good call.

    The alteration I was skirting around involves the addition of ONE OF THESE.  The power supply wires get split to power the auxiliary mosfet board as well as the mainboard.  The Bed wires get cut and the feed from the mainboard becomes the signal to the mosfet, and the output from the mosfet then goes to the bed.

    Since the bed is controlled by a bang-bang / on-off type of switch, moving the bed power surge off the mainboard allows smooth power to the hot end (which is PWM rather than bang-bang).

     

    I have an all day print running.  I'll try to get to your gcode tomorrow.

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    Posted · Wobbly Vertical Walls On My 3D Prints

    OK thankyou very much

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    Posted · Wobbly Vertical Walls On My 3D Prints

    The temperature does seem very steady on the bed and hotend when printing though. It is very strange as if you google my problem, very few other people hav e had it. 😣🤔🤔

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