Ender 3 Pro - Clogging nozzle and skipping extruder on second layer

[Gooz74]

Hi all,

recently I have been experiencing a strange problem with my Ender 3 Pro. Like I mention in the title, from the second layer on, the extruder starts skipping what results in a clogged nozzle.
I've been trying to find what the problem can be but without any result. I will attach a picture of the last print where I had to stop the printing on the second layer.

Things I've already tried to solve (in this order) the issue but without any result:
- Tried another spool
- Levelled the bed
- Tried another nozzle
- Checked the Z offset (BL Touch)
- Tried a new bowden tube
- Tried a new hotend + bowden tube + nozzle + extruder

I have managed to print a small test cube of 20x20x20mm and the Z axis measures 19.88mm.
When I look back on when the issue started, I would think this was together when I upgraded to Cura 5.8.0 (don't know if there can be the issue).

I will try to go back a (couple of) version(s) of Cura later on to see if this is the issue.
I hope there is anybody that can help me finding the issue so I can start printing again.

[Bikeracer2020]

Suggest....... print a 60mm square 0.2mm or one layer thick and check the layer.

Take it off the bed and see if the extruded filament shows daylight between each extrusion and little or no adhesion to adjacent extrusions, if it does, the nozzle is too far from the bed for the first layer.

If it looks like a rough sea with waves, the nozzle is too close for the first layer.

Adjust the 'Z' offset in the slicer until you are happy with the first layer.

[Gooz74]

Hi Bikeracer2020,

Thank you for the suggestion.
I started printing the 20x20 square of 0.2mm a few times and each time adjusting the Z Offset in the slicer.
I now have a firm and good base layer. The offset ended on 0.125mm.

Although there is a good base layer, with a normal print, on the start of the second layer, the extruder still starts skipping until the nozzle is clogged and no filament is printed.
Hope there is another solution.

[Bikeracer2020]

Possibilities.....

Filament grinding and clogged extruder teeth.
Bowden tube route causing binding.

Is it an all metal hot end with a proper heat break above the heater block? If not it could be heat creep perhaps from deterioration of bowden tube in the hot end and plug of filament is happening.

Any tangles in the filament windings on the reel?
Nozzle temp too low and filament not melted fast enough to extrude properly.

Perhaps try a bigger test square.
Search for Youtube videos on extruder clicking and extruder tension.

[Gooz74]

Hi Bikeracer2020,

I doubt if it's anything to do with the extruder (dual gear metal extruder), bowden tube and hotend (original Ender 3 pro hotend) since those are all brandnew.
I changed them trying to find the issue.

Next two things I'm going to try:
- Going back to Cura 5.7.1 and print the same case
- Measuring the height of the Z-axis on the first layer and measuring the height of the Z-axis on the second layer and see if the difference is exactly 0.2mm.

Any other suggestions or things I can try are always welcome. I'll keep you posted

[Gooz74]

We're a bit further in the quest of finding the reason why all my prints fail from layer two onward.
Today I tried to print the 60x60 square but instead of a 0.2mm height. I wanted to print a 0.8 height and measure the height from the Z axis to the bed on each layer on both sides of the axis.

On the first layer I measured left 49.2mm and on the right 49.3mm. On the second layer I also measured around 49.2 on the left and around 49.3 on the right
The measuringtool I use is a manual caliper but I'm sure I didn't measure the 0.2mm I would expect.

Any help on calibrating the z-axis is highly appreciated

[Bikeracer2020]

Hi Bikeracer2020,

Thank you for the suggestion.
I started printing the 20x20 square of 0.2mm a few times and each time adjusting the Z Offset in the slicer.
I now have a firm and good base layer. The offset ended on 0.125mm.

If you now have a 'Z' offset of 0.125mm in the slicer settings suggests to me that the initial offset when bed levelling was set too close, slicer offsets are usually done in 0.01mm to 0.05mm increments to fine tune the first layer.

[Gooz74]

Hi all,

I'm back with an update on the clogging of my nozzle during printing. Unfortunately there is still no solution and I don't know what to try next.
Since the last time, following things were tried/updated.

- Level the bed 100%
- Install Klipper instead of Marlin
- Install a dual Z-rod (during this installation I noticed that the screws on the brass leadscrew were very loose, tighten them a bit)
- Revert to Cura 5.7.2 (because the issue started around the time I updated to Cura 5.8.0)

After the installation of Cura 5.7.2 I was able to print one cube 20*20*20 without skipping of the extruder but with the next print, everything came back.
I'm completely out of options at this moment. Hopefully anyone has any other sugestions to this issue.

Attached there is a picture of the filament that I retracted after the extruder starts skipping. You can see a part of the filament that is wider what makes the nozzle block and therefore the extruder skip.
On the part where the filament is wider, it got to 2.16mm where the normal width of the filament is 1.74mm measuredClogging.jpg

[Bikeracer2020]

Hi all,
Attached there is a picture of the filament that I retracted after the extruder starts skipping. You can see a part of the filament that is wider what makes the nozzle block and therefore the extruder skip.
On the part where the filament is wider, it got to 2.16mm where the normal width of the filament is 1.74mm measured

Does the bowden tube go from the top of the hot end and right down inside it until it contacts the back of the nozzle, or to just below the top of the hot end?

The measurement of 2.16mm suggests to me that it's the clearance for the bowden tube down the inside of the hot end to the nozzle, although I have absolutely no knowledge of any Creality parts or how they are put together.

Unlikely to be a slicer issue.

[Gooz74]

Hi,

Yes the bowden tube fits perfectly. For ruling out the bowden tube, I replaced it with a new Capricorn bowden tube.
To install it, I did the following:
- Retracted all the filament
- Removed the bowden tube
- Unscrewed the nozzle a half turn
- Inserted the new bowden tube against the nozzle
- Fastend the nozzle.

Still no result and the clogging continues.

I also printed a large testprint for the first layer (see attached). The layer is not 100% but I think it is very good (on the corner of the triangles you see a bit less plastic).
The start of the printing went well so I thought I could rule out that it had to do with the first layer but after around 40 minutes into the print (78%), the clogging appeared and no more lines were printed.
You can see that where I marked with arrows, there are 3 lines not printed before I cancelled the print
The layer was printed at a speed of 30mm/s with retraction enabled (2mm at 50mm/s). No temperature change was noticed anyware on the bed or the nozzle.

I still have no idea what can be the issue since almost every part is new and replaced (except the main board ) like mentioned in previous posts.
I'm so close of ordering a new printer but there has to be a solution out there?

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