Having problems with Anycubic Kossel Linear Plus calibration
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Started from scratch (saved the working config to be sure).
Got bed heated to 70C, lowered nozzle to scratch the sheet of paper at center. Removed the paper and lowered nozzle -0,8 mm (measured paper thickness) so it was touching the bed (at least i assume).
Set that height to be Z=0.
Used G30 S-1 several times to determine the probe Z height. Saved it to config.g.
Rebooted printer and started S6 autocalibration. Got result about 0.048. Saved it with M500.
Measured Z offset at all points from bed.g with G30 S-1 and updated bed.g with H for each point.
Run S6 autocalibration again and got promising result:
Calibrated 6 factors using 16 points, deviation before 0.016 after 0.010. Saved with M500.
Subsequent calibrations gave results around 0.007.
So i tried running test print with 9 20x20 squares all over the bed with First layer height = 100 and First layer width = 100. Almost all came out fine except for one in the front and one at center.
After cooling, cleaning the bed and heating it back to 70C i used G30 to provide Z=0 datum and used G29 to create bed mesh. Results were rather good:
305 points probed, min error -0.091, max error 0.168, mean 0.034, deviation 0.043 (peak points at max radius).
Printing with bed mesh active and same slicer parameters gave exactly the same result as before.
So i tried to use First layer height = 150 and First layer width = 90 as i did before. Print came out almost the same as the one without bed mesh active. Again not sticking at center and front. I do not understand, as it looks like bed mesh is not working.
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it looks like bed mesh is not working.
To be sure, just enter G29 S1 from the console before you start your print.
Apart from that, the max. error from probing is quite high - either your bed surface is deformed or the Z-speed setting for probing is too high.
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@infiniteloop
I have included G29 S1 into starting script in slicer, so the bed mesh is loaded (checked with M122).
The bed is deformed indeed, but not that much (+/- 0,16 should be compensated without major problems with bed mesh, i assume).
Probing speed is F120, should not be too fast. -
Probing speed is F120, should not be too fast.
Indeed, that’s rather slow.
+/- 0,16 should be compensated without major problems with bed mesh
That depends. The distance between probing points may ignore some details. I don’t know what your current hight map looks like, but according to your latest test prints, it might be interesting to have a closer look at the two areas where the filament delaminates.
For that, you can define a special grid to probe, just one area at a time, with a very narrow grid spacing. The resulting hight map is like a look through a magnifying glass.
Of course this will not cure your problem, in the best case, you only get a better understanding of what happens.
An alternative explanation for the observed delaminations might be a damaged surface, damaged in the sense that the coating in these areas does no longer stick well with the filament.
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@infiniteloop
The mesh is dense (305 points).
As for the delamination reasons - looks like the nozzle is a bit too low at that points. Babystepping +0.05 solved this, but this again is not permanent solution... -
The mesh is dense
Too lazy to do the math, but the resolution is at approx. 10 mm - not enough for a close look. But talking about babystepping: Do I understand you right that this is only true for prints in these two areas, or does this work for the whole print bed?
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@infiniteloop
Babystepping +0.05 works for the whole print. At least it did not make the other parts being printed worse. -
Babystepping +0.05 works for the whole print.
Then, you simply subtract 0.05 (mm) from your Z probe height - which is exactly the same as to set the babystepping to +0.05. It might be worth trying some even finer adjustment by subtracting one or two more hundredths. Good luck!
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@infiniteloop
Did that before and after autocalibration with new Z probe height (correct direction - subtracted 0.05, double-checked that) and creating new bed mesh ended with printing mid air... Which is strange. -
@infiniteloop
Did just as you've suggested (Z probe height - 0.05) and surprisingly it did work (i have not changed heightmap.csv this time).
Print comes out with almost acceptable quality:
photo1
The only thing that bothers me is that defects at the start of each print:
photo2 photo3 photo4
it happens after retraction and moving to new coordinates, so i suspect this is due to incorrect retract settings in slicer.
For now i use (bowden tube 640 mm with ID 2 mm):
Retraction distance = 8.0 mm
Extra restart distance = 0.4 mm
Retraction vertical lift = 1 mm
Retraction speed = 100 mm/s
Coasting distance = 0,25 mm (was not able to make Pressure Advance work yet).
Z vertical speed = 40 mm/s, movement speed = 200 mm/s -
@SnakeSP Ah, spaghetti printing! Maybe you should switch to some eatable filament?
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Print comes out with almost acceptable quality
First things first: Congrats! One problem solved. What happens when you create a new height map remains to be seen, that’s the next step.
Your photos look familiar to me, I’m in the middle of the same fight with my own printer (just a mean cartesian, bowden setup). So, I can’t provide a solution yet, only two observations:
Print results became better when I reduced the retraction distance (currently at 6 mm).
Your retraction speed looks way too high - I don’t dare to go beyond 30 mm/s.And yes, pressure advance is a hot topic in the forum, I just try to learn about that from the wise guys over here…
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@SnakeSP Sorry for that…
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@infiniteloop
As for retraction speed - i tried low speeds (30-40 mm/s) and got way too much stringing. But will try to lower down for experiments.
Distance - yes, looks too much, will lower it. -
…got way too much stringing
With PETG, in my case it helped to lower the hot end temperature a bit (-5 deg.).
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@infiniteloop Yes, lower temperature reduces stringing, but i'm already at 240 С for the first layer and 220 C for all higher layers. 220 C is the lowest temperature recommended by my filament manufacturer.
So looks the only 3 parameters i can play to reduce stringing are Retraction length, retraction speed and coast at end. -
220 C is the lowest temperature recommended by my filament manufacturer.
My PETG is rated at 210-220 C. Worked for my Aero clone the printer came with, but when I mounted an original E3D water-cooled design, I had to go with 235-240 C instead. Everything is relative…
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@SnakeSP said in Having problems with Anycubic Kossel Linear Plus calibration:
For now i use (bowden tube 640 mm with ID 2 mm):
Retraction distance = 8.0 mmyou might want to build flying extruder.
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@Veti That's interesting, but not in nearest future as it is rather complicated.
