Trying to figure out this zits or holes  

  RSS
Sid
 Sid
(@sid-2)
Active Member

Hi everyone,

I'm having issues with my Prusa Mini. The object is sliced with PrusaSlicer and the seam is configured as 'rear' but the seam looks more like 'random'. I'm having this issue with all of my prints on the Prusa Mini. With my MK3s i'm not seeing this issue.  What could cause this issue to hapen?

 

 

 

 

 

The gcode file i've uploaded here: https://easyupload.io/lx7spb

 

Posted : 15/04/2021 7:28 am
Diem
 Diem
(@diem)
Honorable Member

What happens when you swap the filament, does it swap the problem?

Cheerio,

Posted : 15/04/2021 11:26 am
Sid
 Sid
(@sid-2)
Active Member

No filament change doesn't do anything. I'm using eSUN PLA+ on both machines. But I see i've made an error with the picture. The picture above is from an gcode with the seam configured as  'nearest' the one below is the one from which i've attached the gcode. Seam is configured as rear.  Prints with this gcode all come out as this.

 

I really don't understand why there are zits at that position. When I look at the gcode there aren't any retractions at that point.

Posted : 15/04/2021 11:38 am
Diem
 Diem
(@diem)
Honorable Member

Interesting.  I originally suspected damp filament which is why I suggested the switch.

Do you hear any noises from the extruder/nozzle when printing?

Gcode is rarely much help.  Please zip a 3mf file (save project from slicer), it will contain the settings we need to diagnose this.

Posted : 15/04/2021 1:56 pm
Sid
 Sid
(@sid-2)
Active Member

If it would be filament the zits wouldn't be at the same positions everything, I think. Don't hear any strange noises coming from the extruder

I've uploaded an 3mf file; https://easyupload.io/wcpmsj

 

Posted : 15/04/2021 2:18 pm
Sid
 Sid
(@sid-2)
Active Member

I've been listening a little bit better and there are plopping noises. I've moved the role of filament to my MK3s and there you can't hear the noise. 

On the Mini there seems to be regularity. After a retraction it takes about 2 seconds and then two pops come shortly after each other. So it looks like it has something to do with the retraction. It may sound strange, but could air be sucked into the nozzle?retraction settings are default.

Length: 3.2mm
Lift Z: 0.2mm

Posted : 15/04/2021 5:45 pm
Sid
 Sid
(@sid-2)
Active Member

Another test with a smaller print. This is the back of the print, seam is configured as aligned.

 

Posted : 15/04/2021 7:31 pm
Sid
 Sid
(@sid-2)
Active Member

Same print, but now with retraction configured as 2.5mm. There's definitely improvement visible. I'm wondering how much retraction other people use.

 

Posted : 15/04/2021 8:00 pm
Diem
 Diem
(@diem)
Honorable Member

It might be a slight underextrusion, but first I would try printing a few degrees hotter.  Also, slowing the perimeter print speed might be gentler on the filament.

Cheerio,

Posted : 15/04/2021 11:07 pm
Sid
 Sid
(@sid-2)
Active Member

This problem is solved. I've changed the default retraction from 3.2mm to 1.5 and prints are perfect now. All the other settings are the same. I'm using eSun PLA+ filament. I would be nice though if someone could explain why the zits are in a different location then where the retractions are. This is still a mystery to me, the only thing I could think of is because there is air sucked into the nozzle at the retraction.

 

Left: 1.5mm rectraction                                                                        Right 3.2mm retraction

 

 

 

This post was modified 4 weeks ago by Sid
Posted : 19/04/2021 8:36 am
Daniel
(@daniel)
Eminent Member

@sid-2

That's the problem, the retraction was too high, I have 1.4mm for PLA, do you happen to own a Bondtech extruder?
And the retraction is standard for me, no matter what brand, with PETG I have 1.6mm

Posted : 20/04/2021 7:49 pm
Sid
 Sid
(@sid-2)
Active Member

In my default prusa mini profile the retraction is 3.2mm. I'm using the default extruder on the Prusa Mini

Posted : 20/04/2021 8:08 pm
Daniel
(@daniel)
Eminent Member

@sid-2

Ok it's interesting to know, I know that the Prusa MINI uses 3.2mm by default, but it just didn't work because I can only use 1.4mm with no problem, but that the problem is also with the standard Prusa extruder occurs is strange because it can't be due to the hotend, because I also use the same setting when converting to V6.

This post was modified 4 weeks ago by Daniel
Posted : 20/04/2021 8:17 pm
Share:

Please Login or Register