Print walls and infill not printing correctly

[Adventurehill1 0]

Recently anything I try to print doesn't turn out. I've tried different plastics, changing the nozzle, changing temperature, and slowing my printer down. It still doesn't print correctly. For some reason as soon as I changed to tree support my prints started failing. I don't know if that's related or not.

 

Printer: Anycubic Kobra Max

Cura 5.4

Extruder temp: (PETG) 250, (PLA) 205

Bed temp: 70

 

computer dragon.3mf

[GregValiant 1,261]

The dragon file is just the model.  Use the "File | Save Project" command and post that 3mf file.  It will have your settings in it.

When a print starts OK and then weird things happen it's often the printer.

Can you hold the extruder motor comfortably between two fingers after a print has been running for a while?  If it is running hot the filament drive gear gets hot and can soften the plastic as it passes through.  That makes pushing it through the bowden tube difficult.

Is the hot end fan running?  No strings stuck in the blades?  The heat exchanger block is free of debris?

When you pulled the nozzle did you clean out the hot end?  Is it the stock unit?  A partial clog can develop between the end of the bowden tube and the back end of the nozzle.  If hot plastic is pulled up in there (by retractions) then it can form a little O-ring and impede the filament.  Cleaning out the hot end and trimming the bowden tube back by 5 or 6mm (make a nice square cut with a razor) and re-installing it snugly against the nozzle can fix that.

[Adventurehill1 0]

Thanks for the quick reply. I've been doing some testing and I think the biggest problem was that i had my machine nozzle size set to 0.2mm and the nozzle I have installed is 0.4mm. i changed the setting and tried to print, but the gear on the extruder motor came loose so I have to fix that before I can test my theory.

competer dragon with settings.3mf

[GregValiant 1,261]

Regarding the under-extrusion, that was probably the loose drive gear on the extruder motor.

The "nozzle size" settings in Cura provide some defaults for things like "line width" and "layer height".  Those are the settings that are important.  You can run them at any value regardless of the nozzle size setting.

Everyone needs to start somewhere so yes, they should match but it isn't a show-stopper if the nozzle size in Cura doesn't match the actual installed nozzle.  Trying to put down a 1.0 line width out of a 0.2 nozzle can be done if you print at about 1/2mm/sec and really hot.

[Adventurehill1 0]

So, after a bit more testing, I discovered that my Bowden tube was melted. I ordered a new one that can withstand a little extra heat and I should soon be back in business. Thanks for the amazing troubleshooting tips.

[Adventurehill1 0]

I received my new Bowden tube the other day and threw on a 3d printer test. I am still getting terrible results, including blobs, uneven walls, under extrusion in the infill, and bad bridging. I would appreciate all the help I can get

[Slashee_the_Cow 279]

If you could provide a .3mf file of a Cura project (get it ready to print, then go to File > Save Project) it would really help... there's a lot of settings that can lead to things going wrong.

 

Also: check your extruder. Make sure your wheels/gears/whatever it has that actually feeds the filament through is/are properly tight. If it can't grip the filament properly that could explain the various under- and over-extrusion problems.

[Adventurehill1 0]

On 1/2/2024 at 10:15 PM, Slashee_the_Cow said:

If you could provide a .3mf file of a Cura project (get it ready to print, then go to File > Save Project) it would really help... there's a lot of settings that can lead to things going wrong.

 

Also: check your extruder. Make sure your wheels/gears/whatever it has that actually feeds the filament through is/are properly tight. If it can't grip the filament properly that could explain the various under- and over-extrusion problems.

Here are my settings. I'm pretty sure my extruder is fine, but I will definitely check it again. Thanks for the help.

PrinterTortureTest.3mf

[GregValiant 1,261]

That model is awful.  The maximum "Overhang Support Angle" for a .2 x .4 extrusion is about 63°.  90 - 63 = 27°.  The 30° portion (60° overhang angle) of that ramp looking feature might make it, but the 20(70°) and 15(75°) are going to fail.

 

When you print something simple like a calibration cube, how does it turn out?

 

Speaking of calibration cubes - have you calibrated the E-steps on the printer?  If you have then did you stop there, or did you do something silly like use a "single wall calibration cube"?

[Adventurehill1 0]

5 hours ago, GregValiant said:

That model is awful.  The maximum "Overhang Support Angle" for a .2 x .4 extrusion is about 63°.  90 - 63 = 27°.  The 30° portion (60° overhang angle) of that ramp looking feature might make it, but the 20(70°) and 15(75°) are going to fail.

 

When you print something simple like a calibration cube, how does it turn out?

 

Speaking of calibration cubes - have you calibrated the E-steps on the printer?  If you have then did you stop there, or did you do something silly like use a "single wall calibration cube"?

I printed a calibration cube, but it shows obvious signs of underextrusion. As for calibrating the E-steps, I haven't done that because I've heard some controversial things about it. I can look into it more though.

[GregValiant 1,261]

There isn't anything controversial about it - the E-steps need to be calibrated on every printer except the very high end machines (which are calibrated at the factory).

It's just changing a setting in the printer so that when it is asked to push 100mm of filament that exactly 100mm is pushed.  This needs to be done.

Here I've pulled the bowden off the extruder.  I would just nip the filament even with the fitting and then use the LCD to push 100mm (might need the hot end above 175).  Nip the piece off and measure it.  The formula is "Target Measurement" / "Actual Measurement" * "Current E Steps" = "New E Steps".

The printer will have a menu that will have the steps/mm for all 4 axes.  The only one that should ever need to be changed is the E steps.  When you are happy with the settings remember to save the settings in the printer.

[Adventurehill1 0]

On 1/5/2024 at 5:25 PM, GregValiant said:

There isn't anything controversial about it - the E-steps need to be calibrated on every printer except the very high end machines (which are calibrated at the factory).

It's just changing a setting in the printer so that when it is asked to push 100mm of filament that exactly 100mm is pushed.  This needs to be done.

Here I've pulled the bowden off the extruder.  I would just nip the filament even with the fitting and then use the LCD to push 100mm (might need the hot end above 175).  Nip the piece off and measure it.  The formula is "Target Measurement" / "Actual Measurement" * "Current E Steps" = "New E Steps".

The printer will have a menu that will have the steps/mm for all 4 axes.  The only one that should ever need to be changed is the E steps.  When you are happy with the settings remember to save the settings in the printer.

So on the Kobra Max I don't actually have an option to extrude filament manually. I was wondering if changing my flow rate would accomplish the same thing, even if it's not exactly "best practice"?

[GregValiant 1,261]

Yes, you can adjust the flows within the Material Settings of Cura.

You should have a "Tune" menu on the LCD.  It's hard to believe they didn't put the E motor in there under the other axis movement commands.

Skins are the best indicator of flow so in Cura: Scale that calibration cube to 50 x 50 x 1mm tall and set Cura to 3 top and bottom layers (at 0.2 layer height).  Set all the flow rates to 100%.

 

As it prints you should be able to adjust the flow from the LCD "Tune" menu.  From the start set the LCD flow to 110%.  As a skin finishes look closely to see if the individual extrusions are welded together nicely side-to-side.  Keep moving the flow up in 5% increments until you see that the skins are going down flat and are welded together.  Note where your LCD flow rate ended up.

Back in Cura go to the Material Settings and set all the flow rates to that new number.  Set the LCD flow rate back to 100%.  Print the flattened cube again.

A magnifying glass is a good tool for checking the top layer.

[Adventurehill1 0]

So, I was able to calibrate my E-steps using Pronterface via USB cable connected to my computer. Unfortunately, the problem is still here. The calibration cube without blobs is from before and the one with blobs is from after changing E-steps. Other than the blobs the prints are nearly identical, with the top surface just looking nasty. Any other ideas?

[GregValiant 1,261]

With Cura set up to slice, use the "File | Save Project" command.  That will create a special 3mf file that will have the model, all your settings, and your printer in it.  Post that 3mf here.

It's really hard to tell what might be going on just from the images.

 

[Adventurehill1 0]

11 hours ago, GregValiant said:

With Cura set up to slice, use the "File | Save Project" command.  That will create a special 3mf file that will have the model, all your settings, and your printer in it.  Post that 3mf here.

It's really hard to tell what might be going on just from the images.

 

Here is the file. This was printed with PETG, with PLA the only thing I do is lower the temp a bit.

CalibrationCube.3mf

[GregValiant 1,261]

In the material settings all of your flows are at 90% except for the Initial Layer.  You are asking Cura to under-extrude by 10% on all layers above the Initial Layer.

Your line width is at .35.  That's OK but your "Skirt Line Width" of .30 is too small for a 0.4 nozzle.  Then you have the "Initial Layer Line Width" at 130%.

 

Here is a generic PLA project for your printer.  Only adjust the Print Temperature and Bed Temperature to your favorites for PLA or PETG.  The print speed is 50 from the second layer up so it would be suitable for either material.

The point here is to see how the printer performs with a bland base profile.  (BTW - I didn't care for the stock "Kobra Max" profiles.)

Here is a project file.  It's a flattened 50 x 50 rectangular shape.  The setting profile is a new one I named "GV Test".

 

 

 

GV FlatCube.3mf

Edited January 16 by GregValiant

[Adventurehill1 0]

The settings you provided seem to work better, the only thing is I seem to have some warts in the top layer where it had to bridge between infill lines. I guess that could be warping due to the fan being on? I used PETG.

[GregValiant 1,261]

PETG is so soupy that the first layer over infill always wants to sag into the infill gaps and the sparser the infill, the worse it gets.

I use the fan for that layer and the results are much better as the PETG hardens before it can sag much.

I have written this post processor (it will be included with Cura 5.7) and you can turn the fan on for a single layer and then turn it off again.  PETG generally doesn't respond well to cooling, but a little can help certain problem areas like the first layer over infill.

Unzip it and put the AddCoolingProfile.py into the "scripts" folder in your Configuration folder.  (You can find it by using the "Help | Show Configuration Folder" command.)

I print a lot of PETG.  My printer E-steps are calibrated for PLA and I have found that setting all the flow numbers in Cura to 105% helps with PETG.  Since the filament diameters measure exactly the same I have no idea why that is, but it works.

 

AddCoolingProfile.zip

 

[Slashee_the_Cow 279]

5 hours ago, GregValiant said:

I print a lot of PETG.  My printer E-steps are calibrated for PLA and I have found that setting all the flow numbers in Cura to 105% helps with PETG.  Since the filament diameters measure exactly the same I have no idea why that is, but it works.

Stab in the dark: PETG is a little more slippery than PLA (but nowhere near as bad as TPU) so a Bowden extruder needs to work a little harder to pull the same amount of PETG through?

[GregValiant 1,261]

The teeth on the extruder drive gear are sharp.  They bite into both materials pretty much the same so I don't think that's it.

It might be shrinkage as it cools but I don't have a way to check that.  Dimensionally there is no difference in the prints.  Visually I can tell (I picked up a microscope somewhere along the way) and that is where the 105% came from.

[Adventurehill1 0]

On 1/16/2024 at 9:50 AM, GregValiant said:

Here is a generic PLA project for your printer.  Only adjust the Print Temperature and Bed Temperature to your favorites for PLA or PETG.  The print speed is 50 from the second layer up so it would be suitable for either material.

The point here is to see how the printer performs with a bland base profile.  (BTW - I didn't care for the stock "Kobra Max" profiles.)

Here is a project file.  It's a flattened 50 x 50 rectangular shape.  The setting profile is a new one I named "GV Test".

 

 

 

GV FlatCube.3mf 100.2 kB · 1 download

These settings have worked wonders for my walls, thanks a lot. Unfortunately, the infill is still struggling.

The infill and my nozzle seem to be in a war, since I can hear the nozzle hitting infill sections and it gets a lot of buildup on it. this was printed at 225 degrees on the extruder and 30% infill with PETG.