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[Solved] Top Layer Filament Spikes  

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AxioN
(@axion)
Eminent Member
Top Layer Filament Spikes

Printing Spikes Comparison

Greetings! This is the first time I am printing something with such a flat, yet complicated top layer. I am seeing a bunch of filament spikes being created. I think this has to do with end of a movement where the print head lifts up and moves to another location.

 

The print on the left is the default PursaPLA profile and default Prusai3 MK3S profile; both are 0.10mm detail, 15% infill, 100% speed, and using the Silver PrusaPLA that came with the printer. The one on the right is using 200 degrees (default is 215 degrees) and a 2mm Retraction length (default is 0.8mm). As you can see there is no difference, yet these are the only alterations I have found for dealing with this kind of issue (unless I am completely misunderstanding what is happening).

 

Anybody have a suggestion as to what I should try next?

Best Answer by Neophyl:

Its not so much the retraction as the z hop.  When it moves from spot to spot the extruder will retract the filament and then move up by the z hop height.  It will then move to the new location, de-retract and continue printing.  

With the direct drive setup 2mm retraction is the recommended MAXIMUM, any more and you risk retracting molten filament into the cold zone and causing a jam.  I would experiment more with reducing the z hop and the temperature of your material as a first step.

"What am I doing here? Narf!" - Pinky, Pinky and the Brain

Posted : 29/10/2019 2:37 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Top Layer Filament Spikes

Its not so much the retraction as the z hop.  When it moves from spot to spot the extruder will retract the filament and then move up by the z hop height.  It will then move to the new location, de-retract and continue printing.  

With the direct drive setup 2mm retraction is the recommended MAXIMUM, any more and you risk retracting molten filament into the cold zone and causing a jam.  I would experiment more with reducing the z hop and the temperature of your material as a first step.

Posted : 29/10/2019 3:45 pm
AxioN liked
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(@)
Illustrious Member
RE: Top Layer Filament Spikes

I think a few have reported reducing retraction and z-hop has helped in many cases. 0.4 retract and similar hop reduction.  And you might try higher temps to better melt the plastic during retracts. And -  some have said filament that has absorbed a lot of moisture is more prone to stringing. I've had mixed results, but it might be worth drying the filament for 24 hours at 50c.

Posted : 29/10/2019 8:32 pm
AxioN liked
AxioN
(@axion)
Eminent Member
Topic starter answered:
RE: Top Layer Filament Spikes

Is Z-Hop the same thing as Lift Z? I don't really have stringing issues, but I did reduce the temp to 200 degrees (from the default 215). I am printing another test right now with Retraction: Length 0.5mm (default 0.8mm) and Lift Z 0.05mm (default 0.6mm).

"What am I doing here? Narf!" - Pinky, Pinky and the Brain

Posted : 29/10/2019 8:43 pm
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(@)
Illustrious Member
RE: Top Layer Filament Spikes

Hop and lift are the same. 0.05 might be low - let us know how it works for you.

Posted : 29/10/2019 9:00 pm
AxioN
(@axion)
Eminent Member
Topic starter answered:
RE: Top Layer Filament Spikes

Decreased Lift Z

I think that did the trick! Left is the original, right is with the adjustments. The spike locations are present in some areas, but they are significantly reduced; a number of them just blend into the topography.

 

Thank you for your help! 😀

This post was modified 5 years ago by AxioN

"What am I doing here? Narf!" - Pinky, Pinky and the Brain

Posted : 29/10/2019 9:18 pm
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