A20M Z-Axis print heights not accurate

[YvonGeee]

Hello,

I noticed that on the Z axis of my A20M the height of the parts is not correct.

I adjusted my steps/mm using a 2x2x2 cm cube and I have very good result on that cube.

Then, I printed this Dowel Puzzle:
https://www.thingiverse.com/thing:2503974

The height is longer than expected on all puzzle parts, and it is not a constant variation as the smaller parts have more delta than the higher ones, +2 to +4 mm added to the wanted value depending on the parts. That is a lot on about 5cm to 8cm height parts.

I was thinking of missing steps but in the end as the result is higher than expected it may me more like "extra steps"?

I'm using default Marlin so far, version 1.8.something, slicing with Cura 4.

Any idea?

Thanks a lot.

Yvon

[William]

Hi, You can check the z-axis step value on the screen,
Whether it is 400, if you need to modify, remember to save the modified value.

I hope this can help you.

[YvonGeee]

Hi William,

Thanks for your involvement.

What I mean is that I did run the cube test, and after that I adjusted my steps/mm as this:

s/mm Default s/20 New Value Change
Head Y 20.4 80.3 1606 78.7254902 -1.96%
Plate X 20.4 80.3 1606 78.7254902 -1.96%
Z 19.7 400 8000 406.0913706 +1.52%
Ext E 19.2 395 7900 411.4583333 +4.17%

After this, and saving, my new cube is well done to 20x20x20

Then I printed this:
https://www.thingiverse.com/thing:2503974

All the puzzle diameters are 25 instead of 25.4 in the stl. so -1.6%

Longer piece is 77 instead of 76.2 on Z, so +1.04%
Next is 62.1 for 61.5 so +0.97%
Next is 51.7 for 51.3 so +0.77%
Last is 47.2 for 46.9 so +0.64%
Box Z is 38.5 for 38.1 so +1.04%

So the higher I print, the higher the difference is, looks normal to me except for the box that is weird according to this previous statement.

So, do you think that a 2x2x2cm cube test is too small to have good precision results on Z?

Any idea?

Thanks!

Yvon

[William]

Hi, Do you count the thickness of the first layer printed,

If you use a 0.4 nozzle, the first layer is generally set to 80% of the nozzle;

Regarding print accuracy, I found the 32nd point about print quality.

https://rigid.ink/pages/ultimate-troubl ... -prints-32

I hope this can help you.

[YvonGeee]

Hi,

First layer:
Line 31: G0 F3600 X120.737 Y120.658 Z0.3

Last one:
Line 110961: G0 F600 X130.495 Y120.572 Z75.9

And as I end up with 77, yes I think I have to review my Z steps/mm and forgot about the cube.

I thought about another method for Z axis calibration:
Using the printer menu, adjust Z to:
- touch the plate (must be zero, or write value)
- move Z up, by 10mm steps, up to 10cm
- using a caliper, measure head to plate

Then check, and adjust.

Redo the measure, may be double check climbing up to 20cm..?

What do you think?

[William]

Hi, You can try to calibrate the z-axis step value.

Remember to save the settings after calibration.

[Jarda3d]

Did you use Z-hop 0.1mm or not? If not, then use it and print it again. Leaky mixing extruder need it else you can lost Z steps. Try my profile for A10M on A20M. Mixing extruder need many options for better print to be disabled or non standard settings used.