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Infill looks like Swiss cheese PETG
 
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Infill looks like Swiss cheese PETG  

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chris.y7
 chris.y7
(@chris-y7)
Active Member
Infill looks like Swiss cheese PETG

Hi and thank you for your help. I'm using the following....

Mk3
Inland PETG (I'm told made by eSun) filament
slicing with Prusa Slic3r 1.39.1
generic PET profile

My prints look pretty good on the outside but my infill seems to be failing. Check the pictures below....

https://1drv.ms/u/s!ApEIZVkQ_KsXq3GSe6uu74TtONV4
https://1drv.ms/u/s!ApEIZVkQ_KsXq3IzQf6-1rBeiTnW

I tried changing the infill speed from 200mm/s to 100mm/s and saw just an ever so slight improvement. I'm very new to 3d and don't really know what else to change. Any ideas?

Is this something that might be affected by a different slicer? I've thought about trying Simplify3D because some people say their prints improved just by using it instead of what they were using.

Cheers
Chris

Posted : 13/05/2018 6:15 pm
Martin Wolfe
 Martin Wolfe
(@martin-wolfe)
Reputable Member
Re: Infill looks like Swiss cheese PETG

Firstly you are on the right track you just have not gone far enough.

All I can tell you is what works for PETG from Rigid Ink as I have not used eSUN PETG. For Rigid Ink PETG the max print speed is 60mm/s. So a further reduction in speed may be what you need. Also if you have no stringing you could try raising your nozzle temperature. Finally PRUSA have updated their settings slightly with Sic3r 1.39.2.

I would also recommend updating your firmware to 3.2.0. Only do this after reading the following Re: Firmware 3.2.0 for Original Prusa i3 MK3 as there are problems with it that you need to be aware of to avoid damage to your printer.

Regards,
Martin

Martin Wolfe

Posted : 13/05/2018 11:11 pm
chris.y7
 chris.y7
(@chris-y7)
Active Member
Topic starter answered:
Re: Infill looks like Swiss cheese PETG

Thanks Martin. I did install Slic3r 1.39.2 and I see they have lower speed on the defaults but only to 170mm/s. I'll play with this setting and see if I can fix the problem I'm having.

I'm very hesitant to load 3.2 based on the comments. I'm so new to this that I need as much stability as I can get so I'll wait for 3.2.1 or whatever it will be numbered.

BTW what is linear advance and the linear correction that the one guy talks about in that thread?

Cheers
Chris

Posted : 14/05/2018 12:01 am
chris.y7
 chris.y7
(@chris-y7)
Active Member
Topic starter answered:
Re: Infill looks like Swiss cheese PETG

Slowing infill speed to 60mm/s seems to have solved the problem (although I've only done one print for test).

I would like to improve the quality of overhangs though. Even a 45d overhang produces a rough looking finish. The model works but doesn't look great.

Cheers
Chris

Posted : 14/05/2018 3:11 am
ron
 ron
(@ron)
Estimable Member
Re: Infill looks like Swiss cheese PETG

For infill

  • Cubic infill makes your nozzle drag material of crossing lines. You may choose Rectilinear. PET stick well to PET and to the nozzle.

  • You could also increase infill width (0.5 or 0.55) to better handle the overhang of the cubic pattern infill. By having the previous layer more consistent, you avoid the drag.

  • You should limit your infill speed with the max volumetric speed. Perhaps Rigid Ink has a limit lower than 10mm3/s (default for standard PET). For 0.2 layer height, 0.45 width, and 170mm/s, the volumetric speed is ~15.3mm3/s. For 0.2 layer height, 0.45 width, and 100mm/s, the volumetric speed is ~9mm3/s. In the first case by default, speed is toped to the maximum volumetric speed (10mm3/s), not in the second case

    • For external overhang

  • Increase the external perimeter width

  • Increase fan speed

    • Posted : 14/05/2018 3:22 am
    chris.y7
     chris.y7
    (@chris-y7)
    Active Member
    Topic starter answered:
    Re: Infill looks like Swiss cheese PETG


    For infill

  • Cubic infill makes your nozzle drag material of crossing lines. You may choose Rectilinear. PET stick well to PET and to the nozzle.

  • You could also increase infill width (0.5 or 0.55) to better handle the overhang of the cubic pattern infill. By having the previous layer more consistent, you avoid the drag.

  • You should limit your infill speed with the max volumetric speed. Perhaps Rigid Ink has a limit lower than 10mm3/s (default for standard PET). For 0.2 layer height, 0.45 width, and 170mm/s, the volumetric speed is ~15.3mm3/s. For 0.2 layer height, 0.45 width, and 100mm/s, the volumetric speed is ~9mm3/s. In the first case by default, speed is toped to the maximum volumetric speed (10mm3/s), not in the second case

    • For external overhang

  • Increase the external perimeter width

  • Increase fan speed

    • Ron, very interesting information. I'm not sure I understand what "volumetric speed" is other than what the help in slic3r says "experimental setting used to set the maximum volumetric speed your extruder allows". The default value is 0 so I'm not sure if that means it is disabled or it auto calculates? Why should this setting be used instead of infill speed to change the speed of the infill? I'm new to all of this so sorry if it's a stupid question.

    For the over hang there is a setting in slic3r called "extra perimeters if needed". It wasn't enabled by default but I'll try it to see if that helps.

    Cheers
    Chris

    Posted : 14/05/2018 2:21 pm
    ron
     ron
    (@ron)
    Estimable Member
    Re: Infill looks like Swiss cheese PETG


    Ron, very interesting information. I'm not sure I understand what "volumetric speed" is other than what the help in slic3r says "experimental setting used to set the maximum volumetric speed your extruder allows". The default value is 0 so I'm not sure if that means it is disabled or it auto calculates? Why should this setting be used instead of infill speed to change the speed of the infill? I'm new to all of this so sorry if it's a stupid question.

    For the over hang there is a setting in slic3r called "extra perimeters if needed". It wasn't enabled by default but I'll try it to see if that helps.

    It is not the volumetric speed in "print profile" which I use but max volumetric speed in filamen settings / advanced. It was debugged and set properly by Prusa last november ( https://github.com/prusa3d/Slic3r-settings/commits/master?after=3611992e48ba3dd36c77d0234604bbb438678882+69 ).
    It tops the flow in the nozzle according to the filament. With the heater in the hotend, you can't soften the filament too quickly.

    Extra perimeters if needed: this feature checks whether adding more perimeters to sloping layers would help hiding the internal infill, thus make the object look nicer. ( http://manual.slic3r.org/topics/draft-quality ). I don't think it is what you are looking for but you can give it a try.

    Given 0.2 layer height and you want to be supported by half of the previous layer. If you have 0.4 external perimeter width for the external perimeter, the max overhang angle is 45°. If you have 0.5 external perimeter, the max overhang is 51°. Or you can decrease le layer height. 0.15 height and 0.4 width gives 53°. I found schemes about that: http://weareprintlab.com/blog/printlab-design-tip-1-consider-overhangs

    Posted : 14/05/2018 3:03 pm
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