Violent shaking on thin infills
I got a new i3 Mega X which I am excited about. I've been using cura for weeks, endlessly trying to get perfect print settings but having extrusion/retraction issues. Finally I tried prusa slicer with i3 mega presets and my results were better with only minimal tweaking, However...
I keep running into two issues, the first is that slicer keeps making these thin bits of infill, seen in purple in the benchy above. My acceleration settings seem normal, around 1800, 8mm jerk. 40-60mm print speeds, but my printer violently shakes as it tries to fill these bits in at high speed, the noise is concerning and the Z axis lead screws actually wobble/vibrate. I can't seem to find a solution.
Secondly I'm using the same retraction speed I was using in cura but it makes a clicking sound on retraction. This isn't the gear skipping and I'm not sure why it's so loud. I turned down the retraction length to 6mm from the defaults and retraction is set to 40mm/s. The model itself prints great but the printer sounds like it's trying to destroy itself.
I suspected gap fill at first but on examination the white lines are following cleanly between the perimeters, it's all those thin purple infills.
Can any of you good people help me find what is causing these issues?
Best Answer by Neophyl:
This is a known issue with PS https://github.com/prusa3d/PrusaSlicer/issues/1054
Sometimes unticking ensure vertical shell thickness will remove some or all of it as Joan suggested. Its highly model dependent though. Often it doesn't. Sometimes increasing your perimeter count can also remove some or all of it. Usually going to 4 perimeters is needed.
As for the clicking, see what is configured in your Printer Settings>machine limits for acceleration etc. Unless disabled PS will usually emit the machine settings into the gcode which will over ride those set on your printer. This can cause issues. Its only in 2.3 that the ability to turn off the machine settings for Marlin was added to the Machine Limits options page. In previous versions you had to choose repetier as gcode flavour as that produced the same gcode but without the machine settings.
The usual thing to do though is to read back the printer settings from its eeprom and then change the machine settings in PS to match. That way even if they are sent it doesn't cause a problem as they are correct. It also has the side benefit of making printing time estimates more accurate as those settings are what Slicer uses for that.
RE: Violent shaking on thin infills
Example of the clicking, it's drowned out a bit by the fan, guess I got too close.
The i3 Mega is one loud machine
RE: Violent shaking on thin infills
Try Unticking ''Ensure Vertical Shell Thickness''
in ''Print Settings>Layers ad Perimeters>Quality settings''
Regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Violent shaking on thin infills
@joantabb
That removed a lot of it, there's still some near the front and in other places. I'll try printing it again.
RE: Violent shaking on thin infills
This is a known issue with PS https://github.com/prusa3d/PrusaSlicer/issues/1054
Sometimes unticking ensure vertical shell thickness will remove some or all of it as Joan suggested. Its highly model dependent though. Often it doesn't. Sometimes increasing your perimeter count can also remove some or all of it. Usually going to 4 perimeters is needed.
As for the clicking, see what is configured in your Printer Settings>machine limits for acceleration etc. Unless disabled PS will usually emit the machine settings into the gcode which will over ride those set on your printer. This can cause issues. Its only in 2.3 that the ability to turn off the machine settings for Marlin was added to the Machine Limits options page. In previous versions you had to choose repetier as gcode flavour as that produced the same gcode but without the machine settings.
The usual thing to do though is to read back the printer settings from its eeprom and then change the machine settings in PS to match. That way even if they are sent it doesn't cause a problem as they are correct. It also has the side benefit of making printing time estimates more accurate as those settings are what Slicer uses for that.
RE: Violent shaking on thin infills
@neophyl
Thanks, I'll try reading eeprom once this benchy is done. It might be an acceleration setting or something as the clicking almost sounds like whiplash at times.
RE: Violent shaking on thin infills
@neophyl
Wait but what is the difference between the settings in the printer profile and those in the acceleration control section of the print settings?
RE: Violent shaking on thin infills
SENDING:M503
echo:Steps per unit:
echo: M92 X80.00 Y80.00 Z800.00 E413.80
echo:Maximum feedrates (mm/s):
echo: M203 X120.00 Y120.00 Z20.00 E80.00
echo:Maximum Acceleration (mm/s2):
echo: M201 X400 Y400 Z60 E10000
echo:Accelerations: P=printing, R=retract and T=travel
echo: M204 P400.00 R3000.00 T400.00
echo:Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
echo: M205 S0.00 T0.00 B20000 X4.00 Y4.00 Z0.10 E8.00
echo:Home offset (mm)
echo: M206 X0.00 Y0.00 Z0.00
echo:Z2 Endstop adjustment (mm):
echo: M666 Z0.00
echo:Material heatup parameters:
echo: M145 S0 H180 B70 F0
M145 S1 H240 B110 F0
echo:PID settings:
echo: M301 P20.00 I0.30 D150.00
echo: M304 P60.00 I0.30 D30.00
echo:Filament settings: Disabled
echo: M200 D1.75
echo: M200 D0
RE: Violent shaking on thin infills
Not sure where the correct places for
echo:Accelerations: P=printing, R=retract and T=travel
echo: M204 P400.00 R3000.00 T400.00
are.
The others I found
RE: Violent shaking on thin infills
@neophyl
There is also the Max acceleration when extruding / retracting boxes and I'm not sure what number belongs there
RE: Violent shaking on thin infills
@joantabb
@neophyl
Thank you both. I'm not sure if everything is 100% correct but my printer is no longer sounding like it's going to damage itself.
Strangely Slic3r handled the thin walls of my cookie cutters far better, but for a full benchy print the results look almost the same.
RE: Violent shaking on thin infills
I think PS doesnt have the separate travel accel field (theres one it doesnt have but I'm struggling to remember the github issue it was mentioned in). From your values above it looks like the Max acceleration when extruding is 400 and max acceleration when retracting is 3000.
As long as you have them as best you can and that the printer is behaving you can tweak them over time if you want. Its good to experiment 🙂
RE: Violent shaking on thin infills
@neophyl
Thanks again for the help. Slic3r isn't quite as intuitive to set up as Cura.
Is there a way to increase flow on the first layer? It's not a huge issue but build plate adhesion isn't as good on the slic3r benchy. I've levelled my build plate with a piece of paper until there is friction when moving it, as instructed in the setup guide. Cura's first layer flow is set to 105% at .25mm and I get a perfect adhesion with no space between the lines. In slic3r at .25mm first layer, I can increase the 1st layer width but it only seems to increase the actual width of the lines and not add any extra extrusion. The lines on the bottom aren't quite as snug together in some spots.
Again not a big issue, most of the time things print fine, but I did lose one benchy because of it while testing.
And yes I calibrated my e-steps :p
RE: Violent shaking on thin infills
@sascha-uncia
Hi Sascha, you can change the flow any layer you like. you could set up custom Gcodes on a per layer basis.
if you put the code
M221 S100
In the start gcode, then the printer will start printing at full flow, then
you could put
M221 S95 in the second layer
to reduce the Flow for later layers...
or you could change the extrusion width for the first layer and later layers
as you can see above the default extrusion width is 0.42mm but you could increase this up to say 0.8mm with a 0.4 mm nozzle.
and / or you could change the first layer thickness to say 0.3mm
Or a combination of the above!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Violent shaking on thin infills
@joantabb
Thanks, I'll try that!