Small issues with first prints

I generated a few test gcodes. It’s the parameter “Enable Acceleration Control”.
I will set M204 T1000 P750 in my start gcode and disable this feature in cura

Hello @brent113 and others.

your sliced benchy with 0,16 layer height cannot reproduce my problem. It’s only visible at 0,08 mm layer height.

I got the idea of exporting my cura profile for you to print a test benchy with this. Only the first layers are interesting to see the proplems on the hull.

I you experience the same issues with this profile, it’s maybe really a configuration issue. If not its a calibration / hardware problem with my printer.

So here is an export of my profile.
For cura its nescesary to limit your acceleration within your start gcode because the cura acceleration control uses deprecated gcodes.

M204 T1000 P750

So please, if you have some spare time, test my profile with benchy on your printer.

Curaprofile.zip (642 Bytes)

Thank you very much!

The better way is a gcode, please share!

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SA350_New_Fine_(slynold)_2011041021_3DBenchy.gcode.zip (2.1 MB)

Hello @xchrisd here is my gcode! Thanks for your efforts!

I will print this today or tomorrow night, my wife is in homeoffice and the printer is next to her :wink:

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Sounds cool! Thank you :slight_smile:

@xchrisd @brent113

Take a look at that :poop:

313 votes and 97 comments so far on Reddit

It could be a Cura bug…

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Hey, i see your gcode does a lot of traveling, have you activated combing in cura?

I guess, less travels mean less failures on the outer wall.
Currently printing your benchy gcode.

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Yes, thats right. Combing is only activated inside the walls.
Also the seam is set to 0/0 mm. I configured this to allow a better observation of the wall printing moves and to force a retraction when moving from the inside to the walls / start.
I obeserved the same issues when these setting were off. So thats not the source of it

Hey, I got your gcode with my temperatures well printed (PETG) .
I doubled the speed after the first top layer, this made a little failure, which disappeared after a few layers.

I guess your machine calibration isn’t perfect yet.

For comparison:
-Print a temp tower and retraction test
-Calibrate your extruder
-Calibrate your Linear advance

I think you printed too hot, this with your slow (12mm/s) outer wall speeds could cause your wall artefacts.

Hope this helps😉

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Thank you!!! This is really interesting and a great help.

Sadly I calibrated everything (take a look at a few comments above, with a lot of pictures. I have no stringing problems), but linear advance - but there it tried different settings with this with no difference.

I also printed faster, and printed slower - no difference, too.

Maybe it’s really a temperature issue with thin layers curling up, and the extruder nozzle hitting against the curls.

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I think i finally got it!
It has several causes.

After seeing @xchrisd Benchy i reflected my prevous findings and brought it together with his settings.
He prints with petg which is printed hotter than pla, also doubled the speed settings.

I read about issues with overhangs, bridges and speed settings, so I slowed down my print a lot. But it did not help. It made my problem worse.

I had the theory that my problem has to do with thin layers curling up, and my nozzle hitting against these curls and plowing them up.

So what’s about lowering the temperature, to reduce the effects ot thermal expansion on thin layers, which causes the curls, and also be faster at bringing on new layer, before the curls can touch the nozzle?

At first I doubled the speed, which reduced the problem a lot.

Than I lowered the overall temperature - and the problem was almost gone.

Here are the pictures:

From bottom to top:

205 C° - 200% speed -> much better, small curls visible, no barnacles
195 C° - 200% speed -> almost gone, micro curls, no barnacles
220 C° - 200% speed -> perfect surface visible, could be the heat bed that welds together the layers
230 C° - 250% speed -> curls and barnacles coming up again stronger ( next picture for details)

Of course the transparency is not perfect, because the temperature is not hot enough to prevent air between the layers, but that could be a problem to solve with better cooling and temperatures above 220 C°

At the moment I dont want to manipulate my extruder with @brent113 cooling mod, as long that i don’t have real problems.
I hope that the dual extruder that will be released has a better cooling solution.

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Okay, I did it.
With @brent113 s cooling mod, 0,08 mm print really acceptable!

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