Printing issues, maybe somebody will help with that

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Hi, I'm fighting with printing problem.
I have artifacts, like orange skin on my prints.
alt text

And motion part of config.g:

; Drives
M569 P0 S0                                     ; physical drive 0 goes backwards Y2
M569 P1 S0                                     ; physical drive 1 goes forwards ZPT
M569 P2 S0                                     ; physical drive 2 goes backwards ZPP
M569 P3 S1                                     ; physical drive 3 goes forwards X1
M569 P4 S0  								   ; physical drive 4 goes backwards E1
M569 P5 S0									   ; physical drive 5 goes backwards ZLP
M569 P6 S0									   ; physical drive 6 goes backwards ZLT
M569 P7 S1									   ; physical drive 7 goes forwards Y1
M584 X3 Y0:7 Z5:6:1:2 E4                             ; set drive mapping
M350 X16 Y16 Z16 E16 I1                        ; configure microstepping with interpolation
M92 X80 Y80 Z400.00 E415.00              		; set steps per mm
M566 X900.00 Y900.00 Z120.00 E1200        	; set maximum instantaneous speed changes (mm/min)
M203 X15000.00 Y15000.00 Z1500.00 E6000.00        ; set maximum speeds (mm/min)
M201 X1800.00 Y1800.00 Z300.00 E3600.00            ; set accelerations (mm/s^2)
M906 X1200 Y1200 Z1400 E650 I30                   ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                        ; Set idle timeout

Printer is cube style kartesian, with 4 Z axis motors, 2 Y axis Motors, bmg direct extruder
Did you see this kind of artifacts?

Veti

just to rule out a slicer problem, have you tried a different slicer like cura or prusaslicer?

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Im using prusaslicer right now, but beta rc2.. Maybe this is the issue. Will try prusa official

OwenD

@button
Seems to me to be over extrusion at the start of every segment. Jerk in config seems ok, so I'd lean towards extrusion modifiers in slicer

Try

Turn off pressure advance
turn on firmware retraction in prusa slicer
ensure RRF output is selected in prusa slicer
ensure slicer isn't over riding jerk and acceleration values
ensure filament diameter is correct and/or turn off volumetric extrusion

Might help to post the output gcode from the slicer

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@OwenD
Yesterday evening discovered same - nozzle is from steel, was printing with PA+CF and somehow nozzle get destroyed. Didnt check after going back to ASA. I changeed extrusion multiplayer to 0.95 and its ok right now... time to check ruby nozzle (or different steel)

3dML

20210103_165838[1].jpg

@button

If the layers with the artifacts look similar to this it is caused by excessive cooling.

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@3dML I found that if I cool to much layers not sticking to each other. Only way is to slow down the print but printing ASA with lower speed then 50mm/s disappointing me...

Ok, I think something is wrong with my setup (I mean mechanical) - I have printed test cylinder and it looks like that:
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Side that looks nice has 29.6 height
Side where you can see elephant feet and a lot of bulbs, fuzzy skin etc. Has 30,1.

Slicer problem or mechanical?

3dML

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There are so many variables it is hard to say. As speed increases every printer setting becomes more important.

I may be wrong but the fact that slowing down fixes the problem make me think it is related to speed and temperature. The only way I found to clean up my print was to slow down also. I got to the point in the test print pictured above that I no longer had accurate enough control over the fan speed. Either the print drooped from too much heat or was cooled too much as in the picture.

I have not printed with ASA but ABS is similar. With ABS the previous layer needs to be above glass transition temp to stick properly. The hotter the better as long as the part is not deforming from heat is my philosophy. As you said at lower speed with too much cooling the layer doesn't stick. At higher speed you will have a point where the filament doesn't stick but because of speed and building pressure caused by the nozzle dragging the filament along with it the previous layer heats enough that the filament sticks all in one glob. This can happen repeatedly over very short distances. It is possible that flex in the X axis lets the nozzle oscillate at higher speeds also compounding the problem.

Another possibility for keeping the previous layer at a higher temp is to increase the layer height.

This is only an experience I had that looks similar to yours not necessarily your problem.

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All the time is overextrusion. Think i missed something in prusaslicer, swapped to ideamaker and quality is much better!

After that I started to checking everything, and when I was printing with infill less then 20% was ok. When increas infill getting worse. I changed infill overlap to 10% and infill flowrate to proper amount and now is perfect!