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Issue with 2nd layer (gaps) also with higher layers.  

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MartinD
(@martind)
Trusted Member
Issue with 2nd layer (gaps) also with higher layers.

I am writing my issue also here, as on MMU2S group there are only few who follow. Sorry for duplicating post, but I am very frustrated.

What is happening: 1st layer is printedok, it is very smooth from top, no gaps, looks pretty, no any issues. As soon 2nd layer start to print there are lot of gaps - as seen on picture. this repeats until top layer is printed - which is again mostly smooth.

What I did - I tried to increase temperature up to 230, but no help, gaps are still there. Tried to cold pull filament 2 times, no help. Cleaned bondtech gears, checked if the gear on extruder is ok and not moving freely checked opposite gear on doors if moves freely, cleaned chamber. Dismantled and cleaned the hotend (removed also heatbreak and nozzle, cleaned them up with heatgun and brass brush. No help at all. Tried second filament, the issue persist. Tried precisely calibrate filament, issue is there, however top layer has new issues (it is not smooth anymore). I am tired of this, do someone have any idea what could be wrong?

 

2nd and 3rd layer - visible gaps

2nd and 3rd layer

First layer (different filament, but the result is same with silver one)

1st layer - very smooth and holding together even in bending

Best Answer by MartinD:

Find the culprit - small threads from the side of belt got to the belt itself (probably caused by friction somewhere), and causes to small skip during fast movement. Will test it thorough to see if that was really the cause.

Thanks Peter for the idea!

This topic was modified 1 year ago by MartinD
Posted : 02/12/2020 7:59 pm
Swiss_Cheese
(@swiss_cheese)
Noble Member
RE: Issue with 2nd layer (gaps) also with higher layers.

Well I don't have an MMU and probably never will, but it looks to me like your under extruding, If I had to guess, since you mentioned that you have cleaned and checked most things, I'd say either your bondtech gears are to loose or PINDA probe is out of adjustment. I don't know much about MM Units so I can't help on that front. it seems that something is stopping the filament from passing at the proper rate, and first layer is slowed and so is top layer. that's probably why they look ok . I'm guessing

The Filament Whisperer...
Posted : 03/12/2020 1:03 am
MartinD
(@martind)
Trusted Member
Topic starter answered:
RE: Issue with 2nd layer (gaps) also with higher layers.
Posted by: @swiss_cheese

Well I don't have an MMU and probably never will, but it looks to me like your under extruding, If I had to guess, since you mentioned that you have cleaned and checked most things, I'd say either your bondtech gears are to loose or PINDA probe is out of adjustment. I don't know much about MM Units so I can't help on that front. it seems that something is stopping the filament from passing at the proper rate, and first layer is slowed and so is top layer. that's probably why they look ok . I'm guessing

Yep, I understand I am underextruding. Today my damn story continues, I am going to replace Pinda with Superpinda by following updating firmware to 3.9.2 and recalibration of printer. As I am dismantling whole extruder (due to Pinda cables) I will also replace the extruder motor I have on another printer - just for test. Could be that it is not working properly on faster speeds (during rapid movements). 

Regarding MMU - it is not causing troubles, I tried to disable it and print some test, the same result.

Posted : 03/12/2020 6:44 am
Swiss_Cheese
(@swiss_cheese)
Noble Member
RE: Issue with 2nd layer (gaps) also with higher layers.

well I wish you luck, I'll rooting for you, hopefully its the PINDA and nothing more.

My advice when trying to trouble shoot is to only change one thing at a time, if you change to many at one time you can sometimes miss the cause of the problem, or even create a new one.

Good Luck

The Filament Whisperer...
Posted : 03/12/2020 7:38 am
MartinD
(@martind)
Trusted Member
Topic starter answered:
RE: Issue with 2nd layer (gaps) also with higher layers.

Swapped pinda for superpinda - the issue persist, I noticed before superpinda I had axes xy perpendicular, now they are slightly skewed

Replaced nozzle with new one (e3d brass)- issue persist

Replaced heatbreak, (cleaned up new nozzle) - issue persist

Replaced extruder motor with new one - issue persist

I will be damned, but I really dont know what else to do 🙁

Posted : 08/12/2020 4:41 am
Peter M
(@peter-m)
Noble Member
RE: Issue with 2nd layer (gaps) also with higher layers.

Make a first layer, and make a picture how it looks like.

Did you check the spring of the gears? Adjust like in the manual.

Did you do a 100 mm extrusion, and measured on the filament if it is pulling enough filament?

Extrusion multiplier, does this work if you make this higher? What happens.

Clean rails and put oil on them, just to be safe.

Check whole printer for loose screws etc.

Posted : 08/12/2020 12:35 pm
MartinD
(@martind)
Trusted Member
Topic starter answered:
RE: Issue with 2nd layer (gaps) also with higher layers.

@peter-m-3

Hello Peter, the first layer is perfect, very consistent and smooth from top side, no any holes or gaps. 

I will try to replace spring in gears, and cleanup and oil the rods just to be sure. And also check printer for loose screws. 

Extrusion multiplier = I tried it, up to 1.07, situation got worse on 1st layer (not smooth anymore) and on 2nd and higher layers I got somewhat better coverage of gaps but still gaps are there, so I returned to 1.00, 

Regarding 100mm extrusion, what exactly do you mean?

Posted : 08/12/2020 12:49 pm
Peter M
(@peter-m)
Noble Member
RE: Issue with 2nd layer (gaps) also with higher layers.

@martind

100mm, I mean, take a pencil mark the filament, measure 100mm on the roll , now extrude 100mm filament with the printer, then measure the filament you mark, then you now if you push enough filament.

Search on google how to do this.

Posted : 09/12/2020 7:16 am
MartinD
(@martind)
Trusted Member
Topic starter answered:
RE: Issue with 2nd layer (gaps) also with higher layers.

Find the culprit - small threads from the side of belt got to the belt itself (probably caused by friction somewhere), and causes to small skip during fast movement. Will test it thorough to see if that was really the cause.

Thanks Peter for the idea!

Posted : 09/12/2020 12:42 pm
ssill2
(@ssill2)
Noble Member
RE: Issue with 2nd layer (gaps) also with higher layers.

I've been having a very similar issue, only starting recently.  I've had my (pre-assembled by prusa) MK3S for a few months and have done a good deal of printing.  Including successfully printing numerous brances of PLA, ninjaflex and various brands of PETG.

Yesterday I was printing a pretty simple model for my wife using the silver prusament PLA and I was having trouble with the first layer.  I ended up going with a .3mm first layer and that looked great, but every other layer looked terrible.  I started thinking maybe it was the filament, but I tried the same print with a known working filament and same issue.

Would someone mind telling me what might be wrong?

Here's the model and a test cube in the prusa.

the model I was printing and a test cube in prusa silver

Here is same test cube print with another filament that I've printed numerous things in successfully.

same test cube in xvico3d pla filament

Before I made the first layer .3mm,  the first layer looked like the second.  I've tried various zOffsets since since, based on research, the ripple is often caused by incorrect zOffset. 

Here's the 3mf of the test cube created in prusaslicer 2.3.0

Zip of 3mf file I used to create test cube

Posted : 18/01/2021 4:03 pm
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