FDM 3D Printer Assessment - Pillar looks terrible

Hi,
Last weekend I started printing the sample ‘FDM 3D Printer Assessment’. Honestly I forgot to disable support in Cura. This eventually caused the irregularly lines of the parts under the platform?!
Rest of the print went quite nice, except the pillars. The look horrible. Any suggestions what the cause could be?
Filament retraction was enabled.

The fact that your towers are leaning evidence to me that there may be collisions taking place between the nozzle and the previous printed layer in the towers. The excess stringing suggests your retraction settings arent working for the material you are using.

Try turning on z-hop at a height of about 0.5-1mm and assuming you are using PLA change your retraction settings to 2-3mm at 25-35mm/s as a starting point and try the print again.

Reducing your nozzle temp a little can also help with stringing. Its best practice to print a temperature tower to calibrate for the best (often lowest) temperature that a particular filament prints well at.

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I suffered the same issue, after much testing I found the issue was that my nozel was not holding the proper temp. Try removing the thermistor and applying some thermal paste into the tube, then reinserting the thermistor. That solved the problem for me.

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Thanks, I’ll try that!

Maybe this might even be the reason for the next issue I have. Today I printed a headphone stand. Looking at the pictures there are some irregularities I don’t understand.

First one is the irregular surface. If I go over this with a finger there are spots on the surface In the other picture there are holes in the surface…

The outer edge of the stand which was printed in Z-Direction is showing a smooth surface in bottom part. At some point in increasing high is getting ugly, but basically on the left outer side of the stand foot. Right is more at the inner side…

I’m really disappointed about the print quality. I already did several auto-level procedures with bed heated and calibrated the extruder.


This is a z seam, all printers will have that and good slicers let you determine where you want it. You can minimize this, and possibly some of the other roughness you have pictures by calibrating your linear advance k value. Alot of the rest of what you have shown appears to be underextrusion.

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Meanwhile, I completed some tweaking. I calibrated the E value in M92 again and set it from 231 to 243. I also set the K value to 0.08 (as it is suggested in many threads). Finally, I did a 5x5 auto calibration which showed a quite reasonable result to mine opinion.

Just the front row a partly the back row of the printed squares are not good. This might even by due to the irregular bed heating. Temperature, especially in the front row is about 15 °C lower than in the center.



I’ll do some more test prints and see how the improvement is.

One more thing, In this thread


I don’t know if I got that right in the part about the extruder calibration multiplier. I printed the test cube a measured wall thickness. It was 1.6 mm. Setting in Luban is 1.2 mm. So, is it correct to set flow within the material menu to 75%?
I’m not quite sure what is meant with “Adjust your extrusion multiplier”…

After some tweaks I reprinted this, remembering to set -hop, adjusting K-value and extrusion twice. It’s looking rarely better, but still far away from good. Next thing I thought was reducing print speed(35?) and temperature (195?)

Any other suggestions??!


Did you say you lowered your flow to 75%?

-S

Not for that print. I was not sure if this was meant with „adjust extrusion multiplier“

To me it looks like you suffer from the same problem I have (see Struggeling with PLA - Nozzle temperature off?) - Hopefully in two weeks or so I will be able to tell if putting thermal paste into the thermistor cavity is helping…

The thermal paste helped my stinging ALOT! Alternatively try turning your retraction to 6.5mm and retraction speed to About 30. I just didn’t like having my retraction set so high as it increases the chance of cloging

I had a brief look at the spare extruder that came along with the Snapmaker. All the wires are fixed there. Do I have to release the screw in front of the heating block to remove the thermistor?

No it should just slide out… refer to this thread for more info:
https://forum.snapmaker.com/t/whats-wrong-with-this-picture-printre-hot-ends/7757

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This is the third attempt with the print. What I did is:

Unfortunately still a mess…
I also did a reprint of the calibration cube with Material flow set to 75% (as initial wall thickness was 1.6 mm instead of 1.2 it should be). With 75% flow it then was 1.5 mm, so no change on that too…

Is there any chance to improve that, or is that basically the best Snapmaker 2.0 can achieve?

You should be printing a calibration cube in vase mode so that you have a single wall thickness only when calibrating your flow rate. You should also use a calibration cube that is flat on all sides, not the one that has X Y Z embossed. This will give you the most accurate measurement.

Your retraction distance seems excessive for a direct drive extruder using PLA, try reducing it to 2mm. Also if you are printing with the Snapmaker PLA, try reducing temp to 195.

Seeing as you are currently tuning for reducing stringing only. I would suggest you get a stringing test model off thingiverse to save you the time and extra material used reprinting the rest of this generic test model.

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I did use the calibration model from this page:


and printed that in vase mode.

But maybe I just had the wrong assumption. In luban the wall thickness is 1.2mm. With 100% extrusion I measure 1.6 mm, where all 4 Walls are very close together(± 0.04mm). I was assuming it should be 1.2mm?!

Good idea about another stringing model. Thanks!

what nozzle size are you using? In vase mode there should only be one wall printed and therefore you would be aiming for the nozzle size. i.e. I use a 0.4mm nozzle and so when I calibrated for flow/extrusion multiplier I would be comparing the measured wall thickness to 0.4mm.

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I’m using the standard nozzle which came with the printer (0.4 mm as far as I know). So probably my mistake was to leave the setting within Luban at the standard (1.2 mm). Meaning I have to set it to 0.4 and print then?!

I’m not really sure if I set it up correct in Luban for vase mode (can’t find this term there). I set:

  • Shell, Top Thickness to 0 mm
  • Surface, surface mode to Both
    and would now add
  • Shell, Wall Thickness to 0.4 mm ?!

You dont need to mess with those settings.

Under Surface, there is a setting called spiralize outer contour. Tick this and it will print the object with a single wall and no top allowing you to measure the thickness of filament extruded in a single wall!

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