Komet
Posts: 2
Joined: Sat Oct 10, 2020 2:32 pm

Blobs on seam

Tue Oct 13, 2020 4:07 am

Hello, I'm a new user of Simplify3D and quite happy with the slicer, its options and the print quality.
I just can't find a way to improve the little blobs on the seam of the perimeters. I know this has been asked many times here but I haven't found a solution and everything I try makes the blobs "different" but doesn't improve the quality. I've looked at the print and the blobs are starting when the printer is ending the infill and going over to the perimeter. It looks like there is a little stop at the point it goes over to the perimeters and then filament is oozing out of the nozzle. I've tried playing around with coasting but even when I increase it up to 5mm (started with 0.2, 0.4...) to see an effect the blob just appears earlier.
I would appreciate any help.

(Printer is a Ultimaker 2+ with Bondtech Extruder and a Duet Wifi board).
Attachments
phil1.jpg

parallyze
Posts: 193
Joined: Fri Jun 05, 2015 4:18 am

Re: Blobs on seam

Wed Oct 14, 2020 4:04 pm

Hi,
Komet wrote:
Tue Oct 13, 2020 4:07 am
I've looked at the print and the blobs are starting when the printer is ending the infill and going over to the perimeter. It looks like there is a little stop at the point it goes over to the perimeters and then filament is oozing out of the nozzle.
Would you mind adding a factory file (File -> Save Factory File As...) so others can have a look at your settings? Is the blob forming before
retracting after the infill or after "un-retracting" when beginning the perimeter?
"Only retract when crossing open spaces" on the "Advanced" tab might have an impact here. Would be good to see settings/gcode because of that pause/delay you mention...

Komet
Posts: 2
Joined: Sat Oct 10, 2020 2:32 pm

Re: Blobs on seam

Thu Oct 15, 2020 11:59 am

I've uploaded the factory file here: https://drive.google.com/file/d/1Fb83Si ... sp=sharing (was too big as attachment)

I'm already using "Avoid crossing outline" and "Only retract when crossing open spaces". So at the time when the blobs appear there is no retraction at all. When enabling/forcing retractions the result looks different but there are also visible blobs and I try to avoid retractions when possible.

parallyze
Posts: 193
Joined: Fri Jun 05, 2015 4:18 am

Re: Blobs on seam

Fri Oct 16, 2020 10:00 am

Komet wrote:
Thu Oct 15, 2020 11:59 am
I've uploaded the factory file here: https://drive.google.com/file/d/1Fb83Si ... sp=sharing (was too big as attachment)
Interesting. So according to the factory files there are absolutely no retracts happening where you can see the spots in the final print?

Looking at the gcode there is no retraction going on when printing that region. But:

Code: Select all

G1 X97.640 Y86.109 E0.7238
; feature outer perimeter
G1 X97.554 Y85.718 F6000
G92 E0.0000
G1 X98.037 Y85.622 E0.0046 F918
There's a G92 each time when switching between features, this might cause the delay you're seeing. Enabling
"Relative extrusion distances" on the G-Code tab will result in this:

Code: Select all

G1 X97.640 Y86.109 E0.0045
; feature outer perimeter
G1 X97.554 Y85.718 F6000
G1 X98.037 Y85.622 E0.0046 F918
This will get rid of the G92 resetting the extrusion distance each time.

Here's a bit more info about the differences of absolute vs relative extrusion: https://www.sublimelayers.com/2017/10/t ... trude.html

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