imrija
Posts: 5
Joined: Sun Aug 19, 2018 5:01 pm

underextrusion at line end

Wed Aug 22, 2018 7:36 am

Hello,

I'm having a bit of problems with extrusion on end of the line. Especially on infill, but I also sometimes have gaps on seams on perimeters.
DSC_3389.JPG
DSC_3396.JPG
DSC_3397.JPG
All layers are affected.

I've tried tuning the linear advance, tried different firmwares (klipper, prusa marlin), different printers (prusa mk3-ish, prusa mk2s),
I've also tried calibrating my extruders again, changing flow rate (the gaps disappears when overextruding, of course).

I've also tried different speeds, tuning retraction, even completely disabling them. Still happening.

The gcode preview in s3d looks okay.

There are no gaps when slicing in slic3r, or printing manually written gcode.

I use .6mm nozzle and primarily .32 layer height (changing to .16 did not help at all).

How do I solve this?

Thank you, Jan.

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DarthRevan
Posts: 450
Joined: Wed Feb 18, 2015 8:29 am

Re: underextrusion at line end

Wed Aug 22, 2018 9:01 am

print slower, disable coasting, try retract while wiping, etc...

imrija
Posts: 5
Joined: Sun Aug 19, 2018 5:01 pm

Re: underextrusion at line end

Wed Aug 22, 2018 2:05 pm

Thanks for your reply. I'm already printing at 35mm/s and slowing down does not help. The orange first layer is on 50% speed, which means less than 20mm/s.
I've tried all the coasting and wiping settings. I've changed everything I thought that might have effect and done 20+ test prints.

Also as I said, these gaps are not present when using slic3r or slic3r PE. I'm able to print without problems up to 60mm/s. Then the hotend starts to have trouble melting filament (large nozzle).

User avatar
DarthRevan
Posts: 450
Joined: Wed Feb 18, 2015 8:29 am

Re: underextrusion at line end

Fri Aug 24, 2018 8:58 am

imrija wrote:
Wed Aug 22, 2018 2:05 pm
Thanks for your reply. I'm already printing at 35mm/s and slowing down does not help. The orange first layer is on 50% speed, which means less than 20mm/s.
I've tried all the coasting and wiping settings. I've changed everything I thought that might have effect and done 20+ test prints.

Also as I said, these gaps are not present when using slic3r or slic3r PE. I'm able to print without problems up to 60mm/s. Then the hotend starts to have trouble melting filament (large nozzle).
Are the external dimensions of your parts the same as when you use slic3r or PE? If not, then I'd suggest checking your filament diameter in Simplify3D against your actual filament's average diameter. If your S3D parts are smaller, I'd suggest increasing the extrusion multiplier. If you're only seeing issues with infill and not external sizing, there is infill extrusion width % and outline overlap which can both likely be increased without effecting the external dimensions.

imrija
Posts: 5
Joined: Sun Aug 19, 2018 5:01 pm

Re: underextrusion at line end

Tue Aug 28, 2018 2:42 am

Hi, thanks for your reply!

My extrusion multiplier is 1, and I enter the average filament width in slicer everytime I replace the spool. I measure it using calipers. I use quality spools which tend to be +-0.01mm.

I'm also doing the linear advance calibration when I get new color from new filament supplier.

Dimensions are correct. but the gap is not present only on infill, also on perimeters. Also only on end.

I've managed to reduce it by turning the retract during wipe off, but my retractions are disabled, so I thought this switch does nothing. And it got just reduced, it is not completely gone as I would want it.

PhillipM
Posts: 21
Joined: Mon Jul 31, 2017 2:25 pm

Re: underextrusion at line end

Wed Sep 12, 2018 2:39 pm

I've been fighting this for 2 years with S3D on thin walled parts, it never overlaps the start of the perimeter enough, especially with bigger nozzles - I've models made with 1mm extrusion widths that are otherwise perfect, but where the seam is there's a great big bloody gap, every time, and no amount of tweaking to retraction, JKN off/on/stupid values, wiping, coasting, (why can't we have a negative coast value?!) will fix it - wiping at best just smears it across a little so there's a thin part there instead.

It's pretty frustrating, and just gets worse and worse the further up nozzle sizes you go.

If the devs want to look at this I've some files this week giving me the same problem and plenty of rejects for photographs.

Fin3D
Posts: 3
Joined: Tue Sep 06, 2016 10:18 pm

Re: underextrusion at line end

Fri Sep 14, 2018 1:50 pm

I also have similar issues. Coasting was on by default, which gave me this kind of seam... (see pictures)
The wall is 2mm, nozzle is 0,8 mm. Later I disabled coasting, the result got much better but not good, not at all (sorry no picture available right now).
Attachments
Simplify3D - terrible seam-b.jpg
Simplify3D - terrible seam-a.jpg

arminth
Posts: 2
Joined: Tue Sep 18, 2018 10:25 am

Re: underextrusion at line end

Tue Sep 18, 2018 10:31 am

I am having the same issue. After a Retract and immediate layer restart, I get under extrusion for about 1mm. At higher speeds, its getting worse. To me it looks as if the material is not extruded fast enough before the new layer starts.
I tried coasting off like you and it was better. A negative restart distance made it extremely worse (which reduced the zits though).

At the moment, I have no idea anymore. The rest of the printquality is awesome in my ender 3 - except restarts after retract.

A hint would be nice!

Cheers
Armin

arminth
Posts: 2
Joined: Tue Sep 18, 2018 10:25 am

Re: underextrusion at line end

Tue Sep 18, 2018 12:14 pm

I tried it again with the following settings and as a total surprise, I got no zits and no underextrusion any more. Increased retractionspeed from 50 to 70 and added a positive restart of 0,4mm.
I am stunned and I still don't understand why this helped. I expected to help with underextrusion but thought the zits would increase.
IMG_20180918_190205.jpg
IMG_20180918_190345.jpg

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