Ender3 Linear rail conv. ghosting layershift bad layerlines

Veti

@jay_s_uk said in Ender3 Linear rail conv. ghosting layershift bad layerlines:

The stock motors are 1500ma and the typical rule for current is 80% of the maximum.

mine are 0.8A and match this description

https://gist.github.com/knoopx/e6c40a009e796203b93a75a3ed6a5ab8

ProntoPrint

I had it before to 1000mA but the layer shift occurred with 800mA.
I went down to 800mA beause of the harsh sound and the bad surface with 1000mA, in the hope of getting better surface to less current and therefore less rough motor management

Veti

your bed seems massive compared to the original ender 3 bed.

did you change to a better y motor?

you can try
https://duet3d.dozuki.com/Wiki/Gcode#Section_M593_Configure_Dynamic_Acceleration_Adjustment

ProntoPrint

Yes thanks the bed is a 6mm fine milled aluminium plate, but the layer shift occured in "X" direction.
The ghosting is on either direction the same, if the mass of the y axis would be the trouble maker it should be different ghosting in x and y .
as you clearly can see on the picture it seems to be the same in both direction.

correct assumption?

M593 I will dig into it sounds very interesting, didnt recognize this before
Thank you very much for the valuable tip!

jay_s_uk

@Veti here is the creality listing clearly showing the 42-34 motors are 1.5A https://creality3d.shop/products/creality-42-34-stepper-motor-with-round-shaft

ProntoPrint

From M593 documtentation:

High X and Y jerk values reduce the effectiveness of DAA; therefore you should set the X and Y jerk limits only as high as necessary to allow curves to be printed smoothly.

What are your jerk settings for a Ender3 linear conversion (disregarding my heavy bed)?

ProntoPrint

@jay_s_uk OK
I will up to 80%= 1.2A even of the harsh sound but this schould at least eliminate the layer shift
I will leave the question open if a high motor current can leave to a worser surface!
May be there is somebody out who can share explicit experiences about the relation of

motor current =? harshness motorsound =? worser suface quality

jay_s_uk

on the noise front theres not that much you will be able to do due to the TMC2660's in the duet 2 not supporting stealthchop.
Some motors will be noisier than others.

For the banding I would look at your belt paths to make sure you aren't running the toothed side on smooth rollers. Maybe look at belt tightness etc to make sure they aren't slack and go from there.

ProntoPrint

@jay_s_uk

Good point !
I checked all the rolers on the belt tensioners and there are toothed rollers as it should be .
I double checked every axis if there isn't any rubbing or continous massive oscilation or vibration when I move the bed or the x-axis,

Though you gave me a very important advise:
The rollers were correct but
what I found out by reducing the belt tension the oscilation of the bed and x-axis could be reduced to a very smooth movment farliy noticable belt drive any more.

so conlcution: it seems that the belts where maybe too tight, but
they feel now so sluggish that I get probably other negativ effects.
If I titen them to my exprience like all my other printers the result is like shown,
on my other printers I do have the same pretention and I can feel the belt oscilating effect
of the teeth but get inspite of that perfect surfaces.

ProntoPrint

little update
I have downloaded a jerk and acceleration test like teaching tech expalins
https://www.youtube.com/watch?v=Mnvj6xCzikM
and have just printed with 1200mA instead of 800mA

same strong belt tension as before (tested this after)

and at least with the testobject and in relation with what I see in his video my print looks pretty good better than in the video.
So as i directly cannot compare (for that I have to print the same housing again) its seems
that upping the amps has done a good job,
try to upload some images but a movie would be better!

Is there anybody out there who can explain why upping the current my lead to this better
result of barly seing ghosting better and consistant layerthickness (but, the test body was only 1 permeter no infill( so there are other things to consider in a closesd filled body!?

ProntoPrint

Seeing all this different situations out of the geometry I would like to see how every single situation and the ghosting in relation to cornering sharpness accelleration straightness speet fits into the shown results.
Thanks in advance,
will add the M593 faktor to the pre-gecode and see if there ist an improvement

ProntoPrint

so now after going through my other post Pressure advance and print time and adjusted all paramters so I now get reasonable results in print time but still getting ringing artefacts

arround corners AND on straight lines.

I strongly belive that the motor current produces a resonance!
Therfore I reduced Motor current to 1000mA again because I see at 80mm/s and have still resonance in the x and y direction

additional with no ringing compensation on, measured 3mm peak to peak an 80mm/s speed, so I applied 26,6 Hz

M593 F26.60 ; cancel ringing at perimeter 80mm/s/3mm=26,6, Hz Dynamic Acceleration Adjustment (DAA)

result: NO noticable enhancement and reduction auf oscillation (ringing) at all!

on all Axis still remaining the same 3mm the ringing is because of the heavier bed as expected more noticable on the x axis than vice versa,

any idea what still causes the ringing even if 593 applied?

Phaedrux

@ProntoPrint said in Ender3 Linear rail conv. ghosting layershift bad layerlines:

any idea what still causes the ringing even if 593 applied?

DAA isn't perfect and can't correct for every cause of ringing. If there are multiple ringing frequencies for instance.

What speed, accell, and jerk values are you using?