Checking print quality of cylinders - lines, blob/seam etc
 
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Checking print quality of cylinders - lines, blob/seam etc  

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hitjim
(@hitjim)
Active Member
Checking print quality of cylinders - lines, blob/seam etc

I just wanted to check ... this seems to be expected behavior per a recent forum question: https://forum.prusaprinters.org/forum/how-do-i-print-this-printing-help/blobs-and-lines-on-outside-of-a-cylinder-minii-petg/#post-414874

The bottom ~1/3 has the default 10-15 gyroid infill. Using all standard "Quality" settings for PLA (Prusament on left, Hatchbox on right). The top is just the 2 perimeters.

Is this as good as we can get for the constraints of models/shapes like this? I don't want to go chasing belt tension, extruder gear troubleshooting etc if I'm within spec. Thanks!!

Best Answer by Dan Rogers:

The consistency issues are fine positioning errors from having a) play in the system b) over-tightened bearings possibly.  You can get much better outcomes than that if you are willing to mess around a bit.

Posted : 19/10/2021 3:22 pm
ARU
 ARU
(@aru)
Active Member
Checking print quality of cylinders - lines, blob/seam etc

Hi Hitjim,

Would you mind giving a bit more data about your prints? Printer type, print speed, layer height, retraction length and speed. The overall dimensions of the pieces.

I get much better results on a MK3S with a 0.6mm nozzle. It seems that there is something wrong with the retraction settings with all the blobs you get.

Regards

 

Posted : 19/10/2021 3:32 pm
hitjim
(@hitjim)
Active Member
Topic starter answered:
RE: Printer and print settings

Hello!

It's a MK3S+ with PrusaSlicer v2.3.3 - I used the defaults for

  • Print Settings: 0.020mm QUALITY @MK3
  • Filament Settings: Prusament PLA
  • Printer Settings: Original Prusa i3 MK3S & MK3S+

The cylinder was ~28mm x 60mm (I didn't save it in the slicer, but could slice and print more again)

I'll attach some screenshots of speeds/layer/perimeter/extruder settings

 
This post was modified 1 month ago by hitjim
Posted : 23/10/2021 5:57 pm
ARU
 ARU
(@aru)
Active Member
Checking print quality of cylinders - lines, blob/seam etc

Hi Hitjim,

Assuming you use good quality of filament (Prusament, Fillamentum or equivalent) I would use a nozzle temp between 200 and 210°C and that your nozzle is not worned out, the belts have a proper tension... 

With PLA, the extrusion multiplier is around 0.98- 1

with the Fillamentum PLA, I use 1,5mm retraction, 0.15 lift Z and 45mm/s retraction speed. all other parameters disabled

On Print Settigs>Layers and perimeters, I often print the external perimeter first and avoid crossing perimeters to improve quality (the later would not have an effect with a cylinder)

You could also try to have 3 shells perimeters to get more thickness.

I would not change every parameter in one shot to give you a chance to understand what happened.

Eventually you could reset your print parameters to default and also use a torture test to better identify issues https://www.thingiverse.com/thing:1363023

May be others have much better idea to share

Regards

Posted : 24/10/2021 8:53 am
Dan Rogers
(@dan-rogers)
Noble Member
Start with defaults - you'll be glad you did

You seem to be printing a .07mm layer height.  That's going to be a mess.

Try slicing your model at .3mm layer height for your .4mm model, set everything to a default - if you have Prusament, choose that profile.  Otherwise, choose a filament compatible generic profile.  

Then try the .2mm

Then try the .15 mm and if you are a glutton for punishment, the .1mm layer height.  Compare results.  Don't mess with all of the settings until you get good results on defaults.

 

Posted : 25/10/2021 7:03 am
hitjim
(@hitjim)
Active Member
Topic starter answered:
These were printed with default settings

Sorry, between my cropped screencaps and errors in my original messages (I'm printing at .2mm layer height, not .02 for these!) - I think I've got folks pretty mixed up.

I'm printing with default Prusa 0.20mm QUALITY @MK3 settings from Prusa slicer. The left cylinder is Prusament Galaxy Silver PLA, the right is Hatchbox White PLA.

The defaults have 2 perimeters. Normally I use 3 for my other printer, but I figured I'd see how Prusa's defaults suited me before customizing.

When my current print finishes tomorrow, I'll try another cylinder with 0.3mm DRAFT defaults.

But if it helps, here are some others in Hatchbox PLA that I used the Hatchbox PLA profile with 0.20mm QUALTY @MK3 settings. They seem to have similar extrusion pattern/irregularity, despite having longer/straighter outer perimeters, and more opportunities for inside seams.

Posted : 27/10/2021 4:06 am
Dan Rogers
(@dan-rogers)
Noble Member
It's a reasonable print

What is the question?

Posted : 27/10/2021 9:48 am
hitjim
(@hitjim)
Active Member
Topic starter answered:
Just trying to set my expectations for stock MK3S+

That was basically my question, whether this was a reasonable print? I think I expected more x/y surface consistency in the layer lines. Seems like I might just be looking at Issue 602 - https://github.com/prusa3d/Prusa-Firmware/issues/602

Maybe I'll try one of the test objects from this video to confirm

I just didn't want to go chasing belt/bolt tension, bearings, z-wobble, extruder assembly issues if this is the expected quality for a stock MK3S+

Thanks!

Posted : 27/10/2021 1:47 pm
Dan Rogers
(@dan-rogers)
Noble Member
Well, you do have some tuning to do - but for an untuned printer seems usable

The consistency issues are fine positioning errors from having a) play in the system b) over-tightened bearings possibly.  You can get much better outcomes than that if you are willing to mess around a bit.

Posted : 27/10/2021 1:50 pm
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