Quality problem, mini stairs along z axis

[DzzD]

On a A20m I got non planar wall, look like mini stairs (see pictures), specialy on cube border along z axis, this is a very small default but I have not this problem with my other printer.

Those mini stairs are constant along z axis on the whole height.

Unfortunatly there is nothing about that in simplify3d print quality guide.

Any idea ?

[horst.w]

.... Your FACTORY-FILE please!


I guess:
- speed
- extrusion to high
- inside / outside ?
- non optimal ratio extrusion width - nozzle diameter - layer height

- mechanical issue ?

horst.w
GER

[DzzD]

.... Your FACTORY-FILE please!

Sorry, wich one ? the print profile is the default one for geetech A20m
Nozzle 0.4
Width 0.4
Extrusion multiplier 0.9 (default is 1.0)
Layer height 0.3
Inside/outside
Speed 40mm/s
Outline speed 50%
Retractation 6mm at 30mm/s

NB: stairs disapear totally in vase mode.

Also stairs height seems to be 4 layers height and retractation occur on each border every 4 layers ( according to simplify3d preview ), so maybe related to retraction or over extrusion as you mentionned, dont know I already lowered extrusion to 0.9...

[DzzD]

Some more tests results :
- Trying with the second extruder (a20m) and a different filament doesn't help, same issue.
- Disabling retractation doesn't help

It is maybe something related to slicing (Simplify3D) because I notice that the nozzle go twice at the same location exacly every 4 layers, and stair's are every 4 layers.

I mean there is maybe something wrong on the slicing, because it go on the outer perimeter, draw it, than get back at the same location it started rather than a bit before, so the nozzle print twice at the location it started the outer perimeter.

[horst.w]

Factory-file,
Menue FILE > Save Factory-File As ....

If it would be a slicing issue, others would have it also. I do not so.

Your setting can not cause this occurrence, I'm printing with 50 - 100 mm/s and my results are proper.

I guess its a mechanical problem with the Z-axis because the issue regularly repeats.
Try to print the cube with only 1 perimeter (NOT vase-mode) and NO infill. Whats the result?

The dots on the preview picture are the points showing the retracts. They are only visually . You can check it off.

H.

[DzzD]

Factory file joined.

The result with one perimeter and no infill is perfect (see attachments).

With that settings, all retractation take place in the same border and even this one is perfect, no blob/no zit/no stairs.

Also, I heard or read somewhere that untighting z axis screws and moving it up and down and then tightening screws again may help align z axis, what's your opinion ?


Edit: before you ask , two perimeters and zero infill works greats too, no stairs

[DzzD]

I really think that this problem may come from the path of the nozzle when using infill. I will investigate more on the generated gcode to see if I am right or wrong. Maybe I missed an option in the slicer but I have done so many tests.

For now here are some results :
Those tests have been performed on two printers a20m, cr10s pro, three differents extruders, three différents filaments, two nozzles 0.4 and 0.6, one slicer Simplify3d.
Layers height : 0.3
Vase mode => render is ok
Two outline + infill 15% overlap infill 15% => render stairs on corner
Two outline + infill 15% overlap infill 0% => render stairs on corner
Two outline + infill 3% overlap infill 15% => render stairs on corner
Two outline + infill 1% overlap infill 15% => RENDER IS ok ! ( I really cant explain this result )
One outline no infill => render is ok
Two outline no infill => render is ok
N outline no infill => render is ok

NB: with layer of 0.1mm all print are ok, with or without infill, at least my vision is not enought accurate to see them...

It is a very small defect, less than half a millimeter, that appear with layers of 0.3mm height, nearly invisible with lower layers height.

[horst.w]

Ok, what I can say to the problem is: the layer height 0.30 mm, related to the nozzle diameter and its extrusion width of 0.40 mm each, is a lot out of range! It makes 75% layer height / extrusion width while values of 30% and below are recommended.
This cause that the out coming material is not pressed enough on the layer below, only laying on it. Beside mechanical problems this may be a reason for the occurrences.

Accurate measurement of the filament with a micrometer screw and a lower multiplier value is also recommended, start with 0.94
Extrusion width 0.48 mm, disable the the speed overrides.
Internal Infill change to grid, 15 - 25 %.
Between the 3 options of starting points you can play and look for the best solution.



Z-axis screws should be fixed only with the adapters to the motors, the other end let swinging free. If the motor adapter has to much play you can try to center it or use instead a short part of fuel hose what is flexible enough.

H.

[DzzD]

Ok, what I can say to the problem is: the layer height 0.30 mm, related to the nozzle diameter and its extrusion width of 0.40 mm each, is a lot out of range! It makes 75% layer height / extrusion width while values of 30% and below are recommended.

Thank you, that make sense, and it would explain why lower layers height remove the problem. I did not know about this 30% ratio, I was thinking it can be higher but thinking about this now, I realize that 75% is as you said is a lot too much.

Let's try...

[DzzD]

I have tried differents settings and I am still unable to print a simple cube with more than 5% infill using 0.4 nozzle and 0.3 layers height.

I wonder if it is possible, maybe the ratio of 75% pointed by Horst is the key and what I try is just not possible at least with a cheap printer ...

Here is the simple box STL I try to print, it is a 10 minutes print (no needs of top or bottom layers), If someone want to give it a try I would love to ear of the settings if someone managed to print it without artifacts on z borders ... (Nb: I print it 75% scaled, so it is 22.5mm box)