Problem with gaps between the inner wall and the filling in the top layer

[evTOM 0]

Hello. I have an Ender 3 3D printer and I have a problem with the gaps between the inner wall and the top layer fill.

Please don't know what it could be? I tried to slow down printing to 50 / 25mnm and also various other settings, but I still can't remove those gaps. Could this be a bug in Cura? Or where can there be a mistake? Why does he only do it somewhere?

Will you be willing to help me even if I have an Ender 3 printer? Thank you very much.

Tom

[Carla_Birch 116]

@evTOM

 

That can be down to a number of settings to be true. Some common ones to try to play with are:

• Skin Overlap Percentage (How much the skin overlaps into the wall path)
• Line Width (You can make the line width a little bit wider so its more likely to close the gaps)
• Flow (Could be to low so you not getting the true Line Width you have set)
• Retraction (Could not be set right so when its doing small paths its not starting off right away)

I would personally play with the Skin Overlap and Line Width settings first.

Edited October 12, 2020 by Carla_Birch

[evTOM 0]

6 hours ago, Carla_Birch said:

@Carla_Birch

Thank you for your response. I tried these settings and it didn't help (see the first photo)). I have flow calibrated and 93.02% is used. I have retractions, see the second photo. But they are set up so that retraction does very little. I have a nozzle temperature of 215 ° C.
It seems to me as if it misaligned the inner wall with a filler circle.

 

[Carla_Birch 116]

If you got a 0.4 nozzle i would have line width set to 0.4 or a little lower like 0.38. For flow i would try it at 100% to see if the gaps get smaller.

 

Why you might have calibrated the flow rate, so items you print need settings tweaked for them.

[evTOM 0]

@Carla_Birch

Thank you for your reply. I tried two prints.

 

1. Printing. Adjusted the wall width to 0.38mm and I left Flow 93.02%. The result: the gap still made.

2. Printing. Adjusted wall width to 0.38mm and Flow to 100%. The result is significantly better, although a hint of a gap is slightly visible in one circle. BUT, the problem was with the extruder. Flow 100% is already a large flow, because in the 4th layer he started to jump very often when he filled the area. This was followed by 2 layers of 50% triangle filling, which helped to level the excess filament and the extruder no longer skipped.

Where else could there be a mistake when making such gaps in a circle? It is strange that he will do this only between the inner line and the fill line.

 

I have an Ender 3 with a motherboard and a basic frimver. Do I have the G-code flavor set correctly?

Thank you very much.

[Carla_Birch 116]

When you said you had the flow set to 100% and it started to skip steps, have you checked the Vref of the extruder stepper motor at all to check it’s getting the right power?

 

I don’t have a ender so I can not really say for sure just what the Vref should be set around for it, but if it’s to low it can make it skip steps when trying to push the filament out.

Edited October 13, 2020 by Carla_Birch

[GregValiant 1,455]

The Gcode flavor should be Marlin.  It is in your machine settings in Cura.

 

I have seen this problem from time to time.  It seems to appear randomly and then goes away without me actually doing anything different.  This thread here describes the same problem.  @burtoogle advised "I would reduce the max comb distance without retract to 10 and use the not in skin combing mode."  That seemed to work for the person having the problem.

[evTOM 0]

Thank you for your answers.

 

@Carla_Birch

I have not checked Vref, I will try to advise and check. But at 100% flow, it can be seen that the extruder is already pushing very much filament. I calibrated the steps for the extruder to a Creality filament in white. From the default value of M92 E93, I adjusted the step value to M92 E98.27. When calibrating the flow of the same filament, I had to change the flow to 95.24%. Now I have another filamet and when calibrating the flow I got a value of 93.02%.
I hope I didn't make a mistake during the calibration.

 

@GregValiant

I tried your recommended settings, leaving the line width at 0.4mm.
In the first attempt, I left everything original (including print speed), I just adjusted the two recommended parameters. The result was bad.
In the 2nd attempt, I reduced the speeds, but there were still gaps in one hole. I don't know what to do anymore.

I also attach the Cura profile from the 2nd print attempt. Can you please see if I have something wrong there? Thank you for your help.

Profil.curaprofile

[GregValiant 1,455]

"I have flow calibrated and 93.02% is used." 

You didn't perhaps use a single or double wall cube to calibrate that odd number did you?  If you did then I have a prepared speech to make.  (It's really more of a rant so I'll spare you at this point.)

 

Suffice to say that if your E-steps are calibrated then flow should be 100% plus or minus a couple percent for variations in filament diameter.  Having to drop 6.98% below the calibrated E-steps just doesn't sound right to me.

So I would make a test model of maybe one sector of the model, and print it starting with the flow at 100%.  You might also look at your current setting for (Shell | Skin Overlap %) of 10% and change it to 20%.  Making one change at a time is preferable since if one helps, then you'll know which change made the difference.

Maybe Carla will see more in there, but that's what I've got.

Edited October 15, 2020 by GregValiant