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I have an Ender 3 Pro modded with the Hero Me Gen 6 air ducts, installed a Creality 4.2.7 mainboard, and updated Marlin firmware to the latest for now 2.1.1 version. I'm printing with PLA only.

It was printing well enough. The nozzle started to wear down so I replaced the nozzle (standard brass one) but also upgraded the heatbreak to a bi-metal one (not all-metal, there is still a plastic tube inside the heatbreak) and a heatblock (standard goldish Creality block). And since that moment, the printer fails to print with good quality starting the second layer

What I tried:

  • recalibrated it with a gauge of 0.2 mm and the first layer is perfect (did not know that could be a thing :))
  • updated firmware
  • tried to tighten screws (as it is recommended here)
  • adjusted Z-axis steps/mm
  • another filament

I can't figure out what causes that thing.

Photo of the first two layers of a printed model; the second layer looking very different

Upclose photo of the printed model showing the difference in the two layers

Zoomed in photo of the printed model showing the detailed differences in the two layers

edited 2022-10-25 23:41

I think it is overextrusion. I tried reprinting object. The first layer was perfect, but second was poor again. There was no difference with cooling or without, no difference printing slower. But flow rate did matter:

  1. 100% flow rate
  2. changed to 85% flow rate
  3. changed to 75% flow rate
  4. changed to 100% flow rate
  5. changed to 75% flow rate

Maybe it is prusa slicer doing its thing. I will try Cura. The only thing that bothers me is that diagonal scratch - that is from the nozzle which makes me think it is too low for the second layer

Difference of other flow rates

edited 2022-10-28 15:53

It's not a slicer thing. I sliced object with Cura and got pretty much the same result. I babystepped z-axis during the print to get nice result. So I think it is either z-axis motor not stepping enough or I need to lower extrusion multiplier in slicer. I will print calibration cube to check if z-axis motor steps up enough

edited 2022-10-28 18:34

Printed calibration cube. Turns out my z-axis steps were off. Model was 19.66mm instead of 20mm. I tuned steps to 407 from 400. That helped a bit (model is 20.02mm now) , but still the same ugly overextruded result. Tried to lower extrusion multiplier to 0.8 and still got the same bad result

edited 2022-10-30 22:11

It is neither nozzle nor heatbreak tube. I checked it using my old hardware. Maybe it is somehow connected to firmware... Or E-steps are off while printing

evgen-baton
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  • Could you explain better what is meant with the 0.2 mm gauge? If that is the initial gap between bed and nozzle for printer Z = 0, then it might be too large. It looks as if the second layer sometimes underextrudes, at the same position of previous lines, but worsening... Strange. – 0scar Oct 25 '22 at 18:37
  • I have a metal plate that is exactly 0.2mm thick. I'm using it to precisely level the bed of a printer. Angus from makers muse uses the same kind of metal plate. – evgen-baton Oct 25 '22 at 19:19
  • It doesn't look like underextrusion for me but more like overextrusion. I thought z axis is not rising heigh enough – evgen-baton Oct 25 '22 at 19:22
  • Print something of fixed height, e.g. a calibration cube, you can measure the size. – 0scar Oct 25 '22 at 22:29
  • "I tuned steps to 407 from 400" <-- **this is absolutely wrong**. If your cube height comes out wrong, it means your bed level is wrong. The nozzle is too close to the bed by quite a bit. The lead screw is not wrong. **Never** adjust steps-per-mm on X/Y/Z, only E. – R.. GitHub STOP HELPING ICE Oct 29 '22 at 05:00
  • Have you altered E-steps from the default value? It looks like you just have extreme overextrusion. – R.. GitHub STOP HELPING ICE Oct 29 '22 at 05:01
  • Yes, I tuned E-steps a bit. it is 97.5 now. I believe it is 100 by default. Checked with a ruller. A 100mm of filament is exactly 100mm now. Why do you think it is wrong bed level? I thought calibration cube shows how accurate your steps are. I do also think it is overextrusion but cant figure out why. My guess for now is something wrong with nozzle (maybe it is not exactly 0.4 and too much plastic comes out) – evgen-baton Oct 29 '22 at 07:18

2 Answers2

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I would go back to the brass nozzle and try again for comparison.

We had a batch of 10 cheap steel nozzles all of which caused problems.

Kilisi
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I think the answer is printing temperature. This shiny PLA I'm using is Eryone Silk PLA. Although the working temperature is stated as 190-220 °C, my 205 °C was too much for it. A temperature of 190-195 °C produces good results though not as shiny anymore. It is three layers printed on the sample below with no problems.

3D printed sample printed with 195 degrees Celsius and showing no printing errors

agarza
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evgen-baton
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