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(Ender 3 Pro with Bigtreetech Board and Touchscreen, BlTouch)

Hello everybody, I want to print something for my family but the hotend gets clogged every time in the same part of the print. I tried:

  • Different Nozzles
  • Different Filaments
  • I cleaned every Part
  • The E-Steps are set right
  • The retraction Setting didn't make a difference
  • The Extruder Position is perfect
  • I tried different speeds
  • Everything else you find on Google with a clogged hot end.

The most odd thing about this is that the problem occurs at the same place every time.

On Flat surfaces are some anomalies, that wasn't there when I had the normal clogged nozzle problems (from: retraction settings, dirty Printer, e-steps false). I think it has something to do with the anomalies.

Another thing I don't get behind are missing layers after the layer change, even when I don't use retraction at all. In The Picture from the side you see the Support with the Layer change problem. After around about Layer 40 there is one Layer missing and the next Layers are not connected anymore. From the top you see the Surface anomaly I don't know how to describe. It would be helpful to know what I did wrong. I am sure I did Everything against a clogged Nozzel but I can be Wrong so tips in this direction are Helpful too. I am quite new to 3D Printing(2 Months) I had the usual clogged Nozzel Problem Solved and It Worked Perfectly. I Tried to Fix It with the same Solutions and Nothing Helped, so I think it is a different problem. Sry for my bad English I am from Germany.enter image description here

enter image description here

I have an Ender 3 Pro with Bigtreetech Board, Touchscreen and BlTouch which I use together with [insert slicer here]. I print in [PLA/ABS/PETG/Whatever Material] at [Extruder temperature] °C. The print bed is set to [Bed Temperature] °C. I use a print cooling fan at [whatever] %. The layer height I set to 0.[x] mm, the line width [line width/extrusion width] from the 0.[x] mm nozzle. The Printing Speed is set to [x] mm/s for walls and [x] mm/s for infill. My retraction is [off / [X] mm at [x] mm/s].

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    $\begingroup$ that loooks like terrible layer adhesion, possibly caused by underextrusion or wrong temperature $\endgroup$
    – Trish
    Nov 29, 2020 at 21:19
  • $\begingroup$ I gonne test with a new Temp and adjust the E Steps again $\endgroup$
    – Ericsonpsy
    Nov 30, 2020 at 7:23
  • $\begingroup$ So the printer stopped extruding entirely after this kind of under-extrusion?If it is then it looks like a heatcreep to me.Happened on my ender3pro before. $\endgroup$
    – FrontENG
    Nov 30, 2020 at 8:55
  • $\begingroup$ Ill look it Up today $\endgroup$
    – Ericsonpsy
    Dec 3, 2020 at 10:05

4 Answers 4

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Conclusion

So I found my mistake: It was the E-Steps I did wrong it over extruded. The best E-Steps per mm are 92 for me. The mistake took place because I took my E-step number from a Video Tutorial about my dual extruder. I found the optimal number by testing out; the formula I got for the E-Steps was in the Video and I think I used it wrong, I'll watch the Video again and look at what I did wrong and I'll write a comment about it. I will test more today to get it perfect but @Trish was right.

Thank you to everybody for their Time.

enter image description here

How the problem was diagnosed:

Did I have a bad Temperature?

First, I tested all temperatures in the range of 190 to 210 °C, and the best looking is 200-205 °C. After that, I tried a different height for my print head which just resulted in the model not sticking to the bed. So I could rule out bad layer height.

This was made at 200 °C, The problematic areas are at the corners and on Flat Surfaces parallel to the heat bed:

This was made with 200 °C, The problematic areas are at the corners and on Flat Surfaces parallel to the Heat bed.

Is the Cura profile the culprit?

I made a new printer Profile to find out if I broke it in the settings. I got the same results.

So I tried every Setting in Cura that could have something to do with that, the only thing that helped a little was using 50% Top Surface Flow:

enter image description here this Picture is with 50 % Top Surface Flow

While testing, I saw that the corners are really bad. I think it's because of the print head acceleration. So, I went back and tuned more...

E-Step Configuration Issue Identified:

Finally, I revisited the video I saw originally and figured out, it might be the E-steps per mm. I went through trial and error to come to 92 and realized, I had mistakenly inserted a number for a different extruder setup.

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I'm an Ender 3 Pro user and I've been through almost every problem this machine has.

  1. If you are on original hotend and Bowden style extruder, then first try the hot end PTFE fix

  1. What the picture may show is a temperature too low, especially on these bad layers. Raise the temperature like you have tried (200 °C is good).

  2. To avoid prints being knocked off the bed, try brim (it's in bed-adhesion in Cura), most people don't use raft anymore. What brim does is to add addition loops on the first layer of your prints and make it sticks as good as possible.

  3. No raft, add brim. Then disable Z-hop, enable combing in Cura.

These steps should be able to mitigate the problem.

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    $\begingroup$ This does not look like a bed adhesion problem but something wrong with extrusion. Temperature may mitigate it, but if your printer is working properly, the entire range 180-220 or more should be "usable" with PLA (i.e. not having this kind of catastraphic print failure) just subject to different strength, cooling/warping, etc. properties. $\endgroup$
    – R.. GitHub STOP HELPING ICE
    Dec 1, 2020 at 21:29
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I use the older 2018 model of the Ender3, and so far I have had only to replace some consumables and my extruder for an aluminium one, some nozzles, and one time a fresh Bowden, and I am golden.

To me, I see 2 problems:

  • You might print too cold. I print PLA at 200 °C, some brands I do print a little hotter.
  • You measured your extrusion rate. That is wrong. You need to calculate your steps per millimeter!

Because I don't know your printer, you need to look at how to calculate your proper steps/mm. I assume you have the Typical NEMA17 motor with a 1.8° per step (=200 Steps per rotation) and 16 Microsteps:

  • $d=2\times r$ diameter of the push-gear = 2*Radius
  • $C=d\times\pi$ Is the Circumference
  • $Step = 1.8°$ & $Ms=16$
  • $S=\frac {\frac{360°}{Step}\times Ms}C =\frac {200\times Ms}C =\frac {3200}{d\times\pi}$ Steps/mm

For a typical gear of about 10.5 to 11 mm diameter, that gives numbers between 97 and 92.5 steps/mm. Use your calculator to establish the minimum and maximum numbers first by using the top and bottom of the gear. Then you can test for the correct number in between these numbers. Depending on how soft the material is, the place for the effective gear diameter shifts: softer materials are closer to the high steps/mm number, harder ones more to the low steps/mm end.

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  • $\begingroup$ @0scar I tried differnt Temps with a Test Cube and Differnt Speeds. Its got better but there are Still 'Anomalies' and The Printer cant print to Long. To day I will search for a Better selution. While Printing some Lines are Getting to big and thats why Flat surfaces stick out alittle. It Seems like a overlap Problem of the Lines. I dont use any overlab Procentige so Idk why therek is a Overlab. I hopefully will find out soon. But I first will ubgrade The Printer with a Camera to Show what I Mean. $\endgroup$
    – Ericsonpsy
    Dec 3, 2020 at 10:03
  • $\begingroup$ @Ericsonpsy can you show a new picture? With some more info, we might help you tune your printer. I have included a template in the bottom of your pot that can help us help you! Please fill in the [blanks] with your settings! $\endgroup$
    – Trish
    Dec 3, 2020 at 10:32
  • $\begingroup$ Today I get the rest of the new Stuff for the Printer and than i Will make new Fotos $\endgroup$
    – Ericsonpsy
    Dec 5, 2020 at 10:12
  • $\begingroup$ @Ericsonpsy Depending on the hardness of the filament the effective gear radius will change: with softer filaments (ABS, nylon, PETG) the teeth bite deeper and the steps/mm increase. You still need to extrude 100 mm of filament, measure the actually extruded length, and correct the steps/mm accordingly. You can also use the flowrate, which will result in the same result but it's a less clean solution. $\endgroup$
    – FarO
    Dec 9, 2020 at 16:13
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    $\begingroup$ @FarO: IMO the cleanest solution is to set the steps/mm to the ideal for perfectly stiff filament, and set the filament diameter (especially nice if your firmware has volumentric extrusion mode) to the effective diameter as it passes through the extruder gear. That way you keep what's a material setting with material settings rather than constantly changing your machine-mechanical-property settings for each material. $\endgroup$
    – R.. GitHub STOP HELPING ICE
    Dec 9, 2020 at 17:42
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I noticed that on my Ender 3, if the belts aren't tight enough, I have a similar problem, but mostly when I print anything circular.

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