Problem printing circles

Phaedrux

I have noticed similar surface quality on circles and smooth arcs but don't get the same exaggerated pause behaviour as seen in your video. I'll try printing your STL and see if I can duplicate it.

Can you post your config.g?
Are you using pressure advance?

OBELIKS

Config.g is in the end of the post.
No pressure advance, I was trying it, but I didn't manage to dial it in.
The worst was on the big circle. And stl was prepared for 0,4mm nozzle, walls are 0,45mm thick.
I just realized, I gave too little information. Printer is cartestian with steel frame, motors are supposed to be these: https://3dprint.wiki/reprap/anet/a8/steppermotor and the board is version 1.03
And I put the octagon and square in so I could see if I have the same problems on them, I guess that would mean that it's not a problem with the board.

T3P3Tony

@phaedrux I also checked the pressure advance @OBELIKS posted his config at the bottom of his post, no pressure advance enabled (thought thar as well after @deckingman's experiences

OBELIKS

Just a quick thought, is there any buffers or cache that can be flushed?

3DOeste

I once had a similar problem with another board and it was too little jerk. The circles came out exactly like yours. I’m not surr it’s the same problem, but increasing the jerk value solve the issue.

T3P3Tony

@obeliks there is a print buffer of moves during printing as the firmware needs to know what the next move is. That made me think about if the issue is related to having very many very short moves. so i looked at the gcode. There are loads of sections like this:

G1 X159.018 Y101.352 E0.16013
G1 X159.019 Y101.357 E0.00036
G1 X159.020 Y101.362 E0.00036
G1 X159.348 Y103.498 E0.16013
G1 X159.349 Y103.503 E0.00036
G1 X159.350 Y103.508 E0.00036
G1 X159.528 Y105.136 E0.12129
G1 X159.585 Y105.657 E0.03882
G1 X159.586 Y105.662 E0.00036
G1 X159.586 Y105.667 E0.00036
G1 X159.727 Y107.824 E0.16012
G1 X159.728 Y107.829 E0.00036
G1 X159.728 Y107.834 E0.00036
G1 X159.775 Y109.995 E0.16012
G1 X159.775 Y110.000 E0.00036
G1 X159.775 Y110.005 E0.00036
G1 X159.728 Y112.166 E0.16012
G1 X159.728 Y112.171 E0.00036
G1 X159.727 Y112.176 E0.00036
G1 X159.620 Y113.805 E0.12092

quite small moves

Can you try using another Slicer as a test to see what difference it makes? I note this is Slic3r Prusa edition version 1.40.1, so maybe try Cura to see the difference?

@deckingman I know there is no pressure advance involved but is this related to the issues you are seeing?

Phaedrux

@obeliks Sorry about that, I think the string of numbers made me glaze over that link.

3DOeste

I just looked at your config.g and I don’t think low jerk values are your problem. I think I’m using the same values...

dc42

I assume you are printing from SD card. The usual reason for this type of issue is that the XY jerk is set too low for the print speed.

OBELIKS

@t3p3tony I will try Cura tomorrow. I don't like setting it up, but I will try. But I know that S3D gives more or less the same results. It's a bit annoying, that the old Anet board gave me no problems like that. But I hope we can get this sorted out.

T3P3Tony

@obeliks try @dc42 and @3DOeste 's suggestions of increasing Jerk first.

OBELIKS

@dc42 I actually went from 20mm/s to 15mm/s just to check. It is also true that it was even worse with my old configuration (I havent stored it. I will check, but I think it is gone). Then the circles were flat on top and bottom.
What jerk setting would you suggest?

dc42

@obeliks said in Problem printing circles:

@dc42 I actually went from 20mm/s to 15mm/s just to check. It is also true that it was even worse with my old configuration (I havent stored it. I will check, but I think it is gone). Then the circles were flat on top and bottom.
What jerk setting would you suggest?

The default value of 600mm/min works well for many users, but some users increase it to 900 or even higher.

OBELIKS

I have them at 900 st the moment. I will make a test tomorrow with 1200 and 600, so we can see the difference. And with Cura.

deckingman

@t3p3tony said in Problem printing circles:
...................

quite small moves

Can you try using another Slicer as a test to see what difference it makes? I note this is Slic3r Prusa edition version 1.40.1, so maybe try Cura to see the difference?

@deckingman I know there is no pressure advance involved but is this related to the issues you are seeing?

There are certain similarities for sure - although I only see it with pressure advance enabled. I've discovered that increasing extruder micro-stepping to 256x from 16x is a work around for my issue, so it would be interesting to know if doing the same has any effect on the OP's problem.

OBELIKS

That is another thing that I have problems with. If I try to give command "M350 X256 Y256 Z256 E256 I0" I get something like "Drive E0 does not support 256 microstepping"
I will try this and the rest when I get home from work.

deckingman

@obeliks said in Problem printing circles:

That is another thing that I have problems with. If I try to give command "M350 X256 Y256 Z256 E256 I0" I get something like "Drive E0 does not support 256 microstepping"
I will try this and the rest when I get home from work.

That's weird, but try this. Leave everything in your config.g as is but add M350 E256 at the end of your drive section (after the M84 command). This will mean that the steps per mm are first calculated using 16x microstepping, then when you add that line, the micro-stepping will be changed x 256 and the steps per mm for "E" will be automatically recalculated.

You're not using external stepper drivers are you?

OBELIKS

No.
I will try this also. But this should work from gcode console also?

Catalin_RO

@dc42 RRF configurator default max jerk is 15mm/s, hence 900mm/min! Maybe 600mm/min is the default firmware value, but any config.g file generated with the configurator will have it overridden. I'm going to experiment a little bit with the idea, by increasing from the current 300mm/min in 50mm/min steps.

deckingman

@obeliks said in Problem printing circles:

No.
I will try this also. But this should work from gcode console also?

Yes