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Sketchup designed "Block with hole" printed solid in Cura
When I export my SketchUp STL model to Cura it looks good in solid mode but in the layers mode some holes are filled up.
To find the reason why, I broke down the original model by deleting the parts that come out ok, and ended up with a block 50x100 mm with a hole 30x20 mm in it.
This simple stucture looks manifold, no double lines etc, and does not have red parts in Cura xray.
Cura shows the model as expected, but in layers mode the hole is filled up. I spent many hours to find out, but so far my only solution is to start over again drawing a complete new model and even then this happens again.
I'm using SketchUp 2019, Cura 4, Meshlab 2020
What goes wrong here? How can I repair this with Meshlab?
STL file available on request.

SketchUp is known for creating unprintable models. Your model may be printable, but has the flaws you've noted due to the way SketchUp manages the model. Consider a different program for creating the part.

Avoid SketchUp. Try Tinkercad, instead.

Try OnShape. It's a browser-based 3D Engineering CAD and it's really good. It's very expensive but you can use it for free if you are willing to share your designs. (I have no interest in the company.)

Or FreeCAD, or OpenSCAD. Also, try healing your model with MeshLab.

Does this answer your question? Disparity between Sketchup STL and Slicer

Problem Statement
SketchUp does not always create STLs in ways that are closed, watertight manifolds - a block with a bore is, if created as a block first and then bored out, actually 2 surfaces if made with SketchUp:

a cylinder with its normals facing inside and no top and bottom
a block that has 2 holes in opposite surfaces

The two surfaces are not connected. As a result, Cura sees two non-manifolds and tries to fix each of them - the cylinder with the normals facing inside is considered an artifact that can't be fixed, the holes in the block are stitched and thus turned into a solid block.

Fixing
To repair the issue, you could load the item into for example MeshMixer, which allows to separate and show the different surfaces (shells) and run a rather good auto-fix.
Another program that, with a little handiwork could help is blender. In blender you can first import the STL, then merge the vertices at the edge of the bore and cut cube and thus turn the two shells into one neatly, then re-export it as an STL. I strongly suggest to just add it to your Steam library if you want to keep it up to date.


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Thermal runaway triggers when raising temperature amid cooldown
I've noticed an interesting behavior on my Ender 3 with SKR Mini E3 mainboard and Marlin 2.0.x bugfix firmware. (otherwise, all other hardware is entirely stock) After the hotend/bed are commanded to cool down, e.g. after a print completes, I have to wait until after they both cool down to ambient before commanding another temperature setpoint.
If I don't do this, the printer most often triggers thermal runaway protection. (usually citing the extruder, but also sometimes the bed) I think this might be due to the thermal inertia in the material between the heater and thermistors, causing a 5-10 second delay in sensed temperature rise. I don't see any reason why thermal runaway should trigger; the Octoprint temperature graph looks completely normal, with no perceptible anomalies.
Is there some way to tune parameters for thermal runaway protection to alleviate this false-positive situation?

Yes there are ways to tune false positives. For Marlin firmware you can find these option in the Configuration_adv.h file.
From the file itself you can read what you need to do:

 * If you get false positives for "Thermal Runaway", increase
 * THERMAL_PROTECTION_HYSTERESIS and/or THERMAL_PROTECTION_PERIOD
 */

Any recommendations for how to go about increasing both settings? One before the other, increased symmetrically?

To be honest, I don't know the underlying problem of this, just try to experiment with one at a time.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Ender 3 nozzle gets closer and closer to the previous layer as the print progresses
I'm trying to print a lithophane with my Ender 3, but the nozzle gets closer and closer to the previous layer,  layer after layer.
I thought that what was causing the problem was perhaps a gear lock due to the fact that the Z rod wasn't parallel to the vertical axis, but after fixing it the problem remains.
The bed is super planar and perfectly levelled and, in fact, the first layer comes out perfectly.
Extrusion is also okay. The printer seems fine in all aspects.
It seems like the seriousness of the problem is proportional to the number of layers, just like the printer is losing a fixed height by each layer.
I've ruled out the possibility of wrong calibration of Z steps because after measuring a cube of 12 cm of height and telling the printer to raise 12 cm the cube fits perfectly under the nozzle with the levelling gap (so perfect calibration).
What do you think may be the problem?

Could you please add an image of a print? Calibration cubes are excellent for this.

Yes I could, but there's nothing wrong with the print except the fact that after few layers the nozzle is practically in touch with the print and after few more layers the print fails completely because the nozzle rams agains the edges of the print. If I manually increase the gap by rotating all bed screws thne it prints fine for few more layers but I have to keep compensating throughout the print. It's a pain!

What layer size are you printing? This must be an issue with missing steps as a result of insufficient torque or something. But strange that it goes to the correct height without printing.

Layer height of 0.12 mm, the torque is good I suppose (I find hard to block the Z rod with my hand). Can it be that the printer is skipping steps due to high resolution? I have not printed rough models yet.

Could  you include your settings? I'm not an expert, but wondering if you are putting down a .12 mm height of material, but you are only incrementing upwards of .1 mm at a time. Don't know how this would happen, but seems logical in my pea brain.

The settings are the default in Cura 4.0 for the Ender 3 and PLA with highest quality.

I was wrong but it didn't let me edit my comment. I'm on 4.4 which by the way is good on my other machine.

have you tried the following: print a 20x20x20 calibration cube. Measure height. Then compare to the 20mm it shall be. If < 19.5, something on Z is wrong. Maybe oil the Z-axis gently

@Trish Yes, came out perfectly. But my other more technical prints fail. What can it be?

I have found a problem (which I don't know if it's related), there are two points one in the X axis and one Y axis that act like point of friction during the print. How do I solve it?

I replaced "bed" with "previous layer" Please confirm that's what you really mean..

@CarlWitthoft Yes, it's correct :)

Finally I've found the damn problem: Adjustable rollers of all axes were flat on one point making layers to shift in all directions.
The effect was less visible on the X and Y axes but it was more notable in the Z axis as the flat part was right from the start of the print. I think that flat part was making difficult for the Z axis to move upward, and making my prints fail when printing at higher resolutions (I guess the finer the displacement the weaker the torque).
It seemed to me that the nozzle was getting closer to the previous layer but instead it was resting (or barely moving) on the flat part of the Z right adjustable roller first and then on the other adjustable roller of the same axis.
To diagnose the problem disable the steppers and moved the axes manually and feel if there are notches, so to speak, in various spots on every axis.
The solution is to replace the rollers with new ones and to not close them too tight otherwise they'll deform over time.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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How to calculate the Vref and X_CURRENT for a TMC2130 stepper driver, knowing the rated current of the stepper motor?
I have written a question about this but I found new information in this video and I want to go more to the point.
My motor "rated current" is 1.4V. I assume that this is the maximum current

The guy explains in the video how to calculate the Vref and the X_CURRENT value of Marlin
RMS current = Max current / 1.41 = 1.3 / 1.41 = 0.92
Vref = (RMS Current x 2.5) / 1.77 = 1.3 V
90% Vref = 1.17 V       // to avoid maximum power in the motor
X_CURRENT = 1170 mA     // magic, I don't know why the guy of Teaching Tech does this convertion

Actually, I have read just now that one person says in a comment of the video:

[...] the numbers are wrong. When populating the current values in Marlin, it's asking for the RMS value in mA, not VREF. If we take the given values and take 90% of what's calculated, we'd end up with [...]

So the new calculation would be:
X_CURRENT = 90% RMS current = 0.92 * 0.90 = 0.828 A = 828 mA

I have also read in the TMC2130 datasheet:

Integrated power MOSFETs handle motor currents up to 1.2A RMS (QFN package) / 1.4A RMS (TQFP) or 2.5A short time peak current per coil.

Questions

Is he right? Why is he converting 1.17 V => 1170 mA directly?
The rated current shown in the motor datasheet is the same as the maximum current?
As 1.170 A < 1.2 A RMS or 0.828 A < 1.2 A RMS, the driver will not shut off, right?
Are my calculations right?


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Weird solid infill for chamfer
I am very frustrated with some weird solid infill issue, mostly due to sloped wall such as chamfer for fillet.
Here is an example. I have a 20x20x20 mm cube with 2 mm rounded chamfer at the bottom shown in the figure.

When I slice it using default 0.20 mm profile, at layer 5 I can see some wiggle solid infill near the wall, shown in figure:

I thought that is to help create the chamfer. BUT, if I increase the bottom solid layer number to 50, at layer 51 (which is way above the chamfer region already), I start to see that same wiggle solid infill again! This can't be correct... Shown in the figure:

I am using the most recent PrusaSlicer 2.2.0
The reason I want to get rid of those wiggles is because they create crazy vibrations which then create layer shift for me...
Any help will be appreciated!

What software did you create the cube in? Also, please post the setting for slicing (most relevant); it appears that there is a solid infill layer at layer 50? Looks as if 2 cubes are stacked...

Stiffen your frame. That should be your foremost concern. Just throwing that in here.

user77232, the wiggles of note are not structurally related, they are coded into the build by the slicer.

What are your wall settings -- thickness, etc.

Please answer in which software the cube is designed.


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Problem printing circles/holes on Anycubic I3 mega
For some time I've been struggling to print models with holes going all the way through from top to bottom. Models without those holes print out just fine. I've spend quite some time on levelling the bed, so I think the levelling is fine. I'm using Cura 4.5 with the default settings (normal profile) for the Anycubic I3 mega.
At first I had the problem of the initial circles not sticking to the bed. This is what it looked like:

Then (after doing a lot of searching on the internet) I changed the following settings in Cura:

Initial layer height: 0.1 -> 0.3
Optimize wall printing order: false -> true

After that the circles seemed to stick better, but still the bottom layer looks quite messy. This is a picture of the bottom of the object printed with these settings:

And this is what it looks like from the top:

As you can see, it still gets quite messy around the circles, and they seem to be detached from the rest of the model.
After this (and doing a lot more browsing) I decided to make the following change in Cura:

Retraction extra prime amount 0 -> 0.07

But to be honest, I have not clue what this really does. This is what the initial layer (of another model) looked liked after changing that setting:

And after a couple of layers it looked like this:

Now (finally) my question, does anyone have an idea on how to make my prints (especially the connection of the circles with the rest of the model) better?
Thanks!

If you don't have a bed leveling sensor you MUST use this technique: https://www.youtube.com/watch?v=RZRY6kunAvs

Have you looked at Cura's  "Show Layers" View to see if anything strange shows up there?

From your images can be seen that:

Your nozzle is too far from the bed (the lines are not touching), so you either need to level with a less thick paper or allow for more friction between the paper and the nozzle. There is also a plugin for Cura to set a Z-offset.
You need to enable Combing mode = Not in Skin and possibly fine tune your retraction settings.
You could benefit from some more adhesion using an adhesion spray.

The combing is likely the biggest problem. All that material is oozing out where it doesn't belong, then the walls are so underextruded they won't stick.


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How can I include seperate Slicing Parameters in my 3mf file
I am trying to write a program that edits a 3mf file by defines different slicing parameters for different stls that I have previously merged into my 3mf file, but I am a little bit confused about the configuration of the 3mf file, and where I would look to make changes in the slicing parameters. Can anyone lead me in the right direction as to where I could look? I'm assuming that I wouldn't be making any changes to the .model file because it seems like it only holds information about the meshes.
Thanks and let me know if it would be helpful for me to clarify anything.

Huh. On a hunch I just changed a copy of a .3mf model to have a .zip file extension, and what do you know, it works! 3mf is just a set of compressed xml.
The zip folder structure I saw included a MetaData folder. I bet you could put just about anything you wanted in there, as long as it doesn't conflict with things other 3mf parsers are expecting to find.
I tested this. I dumped an unrelated pdf file into the folder and re-zipped it. Both MS 3D Builder and Cura were able to open the updated file just fine. However, saving the file again in 3D Builder did not preserve the PDF.
I suppose there's a lesson here, too: we may need to be wary of models we download off the internet. They could include literally anything.
This also raises an interesting possibility: password protected 3mf files. If 3mf is just a zip container, and zip files can have passwords, it follows logically that 3mf files can have passwords.

I suppose there's a lesson here, too: we may need to be wary of models we download off the internet. They could include literally anything.

wel 3mf could, but not a pure STL - try opening those and you get garbage...

I think stls just store a series of coordinates describing polygons. You can easily read/write to it but the flaw of the 3mf is that it is simply a zipped file, but having multiple files inside the 3mf allows it to store more information.

authors: Елена Рубцова


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Anet A8 moves down into piece, destroying it, just before the printer is set to finish
I hope someone can help me figure out what's going on with my printer. I have been printing a couple of pieces and it's been printing perfectly. But for some reason every now and then, the printer moves down into the piece just before it finishes printing (after the final top layer) and completely wrecks the piece. I have no idea why this is doing it, and nothing I haven't changed the G-code since. to prove this, I printed an old model that I had on my computer, and it still managed to do it. Please help I have no idea why it's doing this.

Hi welcome to 3DPrinting.SE! With "before finishes" you mean that there are a few layers to go, or after the last layer?

I mean on the very last layer. To confirm, I just watched it finish the last layer and begin to move downward into the piece and melt it. I have no idea why it's doing this

Sometimes if the carriage is heavy, and the steppers are depowered, the carriage drops, if the nozzle is still hot, then it will dig in the print. The alternative is that you command the printer to dig into the print. Please share the last 30 lines or so of the G-code file you print and possibly the end G-code.

Look into question: 3D printer ends print by sinking in to it and getting stuck, this may answer your question?


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Prusa MK3S weird 'Blobs' on PLA print surface
This is the first time I've run into this problem and it seems very confusing. I wanted to print a simple functional part out of PLA and although the first few layers were fine, the 6th/7th layer started to have some weird 'blobs'/deformations on it. I don't know how to fix it and the problem didn't go away after changing the filament. I suppose the problem is related either to my settings or the printer. It is very weird, I fully calibrated the printer right after the first fail.
Settings:

nozzle 215 °C
bed 60 °C
speed 100, 50 mm/s for bridges
cooling 100 %, but no autocooling in order to print faster
using PrusaSlicer

Photo:

Have you tried lowering your print temps? I'm wondering if your 215 °C is a bit warm for your PLA. Try bringing the temps down to 190 °C and see how it goes.

Not hinting to the thick blobby infill, it looks at if 100 mm/s is way too fast for your printer, look at corners and infill reaching perimeters. The print quality is terrible.

@0scar I thought that Prusa MK3S could reach up to 100 mm/s print speed. I rarely print slower than that and I still get decent quality. Maybe the surface my printer is standing on is uneven or there was some kind of wobble. I'm not sure why, but tightening the screws and cleaning the moving parts from dust, etc. helped. I also reduced the Z distance between the nozzle and the bed from 1.050 mm to 0.950 mm.

But clearly, it is too fast. You might need to get the nozzle closer to the bed it doesn't look like it is compressed/squished.

@0scar The issue is fixed by now. To my surprise, I actually had to get the nozzle higher and it worked.

@0scar Of course

After hours of trying to fix the problem by trial and error I found that getting the nozzle slightly higher by approximately 0.1 mm was the solution. I cleaned the rods from dust, tightened most of the screws again and calibrated the printer.
I don't encounter this problem anymore even while printing at 150 mm/s speeds.

this hints you miscalibrated your printer - you want a gap of 0.1 mm between nozzle and bed in the 0


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Issues with print Prusa i3 infill breaking and causing clogs
I'm having some issues with my Prusa i3 prints. I'm trying to print the default beer opener print that came with the Prusa's memory card but the infill will break causing clogging and now allowing the print to finish. I've attached a picture of one of the failed prints.

I've checked Prusa's website and tried tightening the extruder gears and made sure the gears are clean. I'm using the PLA sent with the printer (1.75 mm) and with a default G-code file so I'm fairly sure it is a hardware issue, but I'm not sure what the issue could be.
Here is the link that I've used to help me troubleshoot.

Hi welcome to 3DPrinting.SE! I doubt whether the infill breaking up causes a clog, I would rather say it is the other way around. As this is a pre-sliced model, a similar question "Infill is rough - how to enhance?" might not be applicable, nor can you do anything about the print file. This rests whether you have the correct material loaded (temperature wise) and a good first layer. Please add by [edit] what material you use and what the print requires and post an image of the bottom of the print.

The issue was the filament sent with the printer was PETG and not PLA like this gcode file called for.

Thanks for posting your own solution, please accept this after 48 hours!

this means the temperature is off by some 30°C.

Try calibrating your Z again. It is hard to tell based on the picture, but it could be too close to the build plate, and thus is dragging while crossing the infill section, or it could be too far away and thus is not getting good layer adhesion.

authors: Константин Ван


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Is PLA safe for masks?
So in light of the in going pandemic, I have begun printing masks for my family and a few friends. As I was printing them the thought occurred to me, "Is PLA safe to be breathing off of?" So that is my question. Is PLA safe to breathe off of or does it need to be coated with, for example, a food grade epoxy?
I am using Matterhackers standard black PLA and a stock ender-3 printer.
Thank you for your time and stay safe!

PLA itself should be safe, at least chemically, but there's no guarantee that additives in a particular filament manufacturer's material are safe. From this standpoint it would be best to use an uncolored "natural" (comes out translucent but cloudy when printed) PLA from a manufacturer who documents that it has no added ingredients. It's also plausible (not saying this is necessarily the case) that there's fine particulate matter produced by heating or in the extruder gear that ends up on the surfaces.
However, in the bigger picture/XY-question, it's unlikely that printed masks provide safety against viral transmission. Especially with a rigid material like PLA, they're not going to make an air-tight fit with your face, and they're likely not air-tight themselves even if they do (due to imperfect extrusion, slight gaps between layers at least intermittently). This could perhaps be mitigated by using a separate edge material to make a tight fit with face, and sealing the print like you suggested. However, once you make it air-tight, it's unsafe for another reason: it's a suffocation hazard! Just because you insert a filter to breathe through doesn't mean that you're actually going to be able to breathe through it properly.
Naomi Wu a.k.a. Sexy Cyborg (well known for working with Creality, open source/OSHW compliance in China, and popularizing the Ender 3) has done a number of twitter threads on what the dangers are and why it's unsafe and irresponsible to be creating air-tight 3D-printed masks if you're not qualified for designing this type of device. Here is one. A highlight:

This results in CO2 buildup. After about 30 minutes your plastic mask, if actually airtight and strapped securely to your face will, before you can take it off, kill you- very peacefully. You'll just slump over and go to sleep, but you'll still be dead.

On the other hand, ear savers, bracing/frame for face shields, and no-touch openers are all more likely to be good uses for PLA.

@JoelCoehoorn, PLA's too rigid to make a good face shield frame.  I'd use something like PETG or ABS.

This is correct - the frames for face shields are the products bring community sourced around the world right now, not masks. I gather they’re printed thin enough and need little enough flexibility that PLA is fine for those.

PLA does not provide the needed flex to make a faceshield holder that is sturdy enough to withstand more than a few bends before snapping.


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Brim around just one section
I'm looking to print this item:

https://www.thingiverse.com/thing:4274950

I want to lay it flat on the bed, 90° to how it's shown on Thingiverse. The problem is there's the one little corner on the end of the piece. When placed flat, this corner makes one side of arch. During the print, this section will build up to have much more material up in the air over a relatively small contact point, until the archway is connected.
I'm worried the section will shake loose from the bed. Is it possible to tell Cura to put a brim around just this section, and not the whole piece?
If I have to, I can edit the model the include 0.13 mm thick section there as part of the file. But I'd prefer to slice for this.

FWIW: I ended up editing the model.

I don't know a way to do that with Cura without breaking it up into multiple parts with different settings for each, but what about just enabling supports? You'd only get a very small amount of support material and it would act similarly to a brim to keep the small part from detaching.

I would enable supports using "Touching Build Plate", and then place a support blocker over the portion that you don't want supports added to.

How will this accomplish what I asked? I only want a small brim, not supports all the way, and the rest of it already directly connected to the build plate.

If you add supports to only the arched portion of the model it will prevent the small section from tipping/prying until it is joined to the main body. The supports can easily be removed while easily allowing you to complete the print successfully.

That adds more material and print time than is needed. Brim is faster/cheaper, if I can do just that section.


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Alternating number of lines for the shell between layers
Is is possible to have alternating numbers of lines for the outer wall between each layer? So, say, one layer will have 3 lines for the wall, the next layer, 2, then the next layer 3, then 2 again, and so on? Even better, if I could group them in twos: two layers with 3 lines, two layers with 2 lines, repeat until done.
I use Cura, but if other slicers can do this I'd like to hear about it, too.

It is possible to get an alternate extra wall in Ultimaker Cura, the option is called Alternate extra wall. It can be used to catch the infill more firmly, strengthening the print.
From Ultimaker support:

Alternate extra wall
This setting adds an extra wall every other layer. This way the infill gets caught between the walls, resulting in stronger prints. For example, if you set the wall line count to two walls and enable alternate extra wall, it will print two walls on even numbered layers and three walls on odd numbered layers.

I've used this option frequently, but I'm not aware of any option that you can change the amount of layers alternating. You can do that probably with the option to set different options for different sections of the model, see e.g. "Different infill in the same part".

I find the claim of "catching" infill between the extra walls somewhat dubious unless you also enable zig_zaggify_infill ("Connect Infill Lines"), which is a really good idea anyway because it vastly reduces travel moves and the associated problems with material loss due to oozing while "combing". With this option on, infill doesn't just start/end at points sandwiched between the extra walls, but has whole dashed segments for roughly half the total perimeter pressed between them.


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Ender 3 pro extruder skipping steps, tried multiple things
I've already asked this question somewhere else but unfortunately I had little luck.
So... my Ender 3 Pro extruder just started skipping steps, as in the gears (and the gear pinion) will rotate but the filament won't flow. It all started when I changed PLA filament to a new roll; I thought it might have been the roll faulty so I've tried a spool that had been working fine until 2 hours before it all started. Nope, skipping with that one as well.
Here's what I've tried doing so far:

Replaced the stock PTFE tubing with Capricorn tubing.
Checked that the tubing is tight and does not have play.
Replaced the whole extruder system (except for the extruder motor) with a metal Creality system.
Performed various cold pulls.
Replaced the nozzle.
Upped the extruding temperature from 195 °C to 205 °C.
Checked that there's the correct distance between the bed and the nozzle.
Yelled at the printer.
Asked for advice to my cats.

None of the above worked, and my cats looked funny at me. Print settings as below:

Filament diameter in the slicer 1.75mm (yes I've checked).
Temperature: 195 °C, upped to 205 °C.
Print speed: from 20 mm/s for the first layers to 50 mm/s for the infill.

I've also reverted back to the old PTFE tubing as I noticed that the Capricorn was giving too much resistance to the filament. Nope, still skipping.
I've noticed that the extruder gear grips quite firmly onto the filament, so much so that when it starts slipping it actually eats away the filament until it breaks. It's almost like there's a clog somewhere but the tubing is clear, the hot end is clear (I've cleared it and checked multiple times), and the nozzle is brand new.
What else can I try? Have I missed something? Apart from the changes listed above (carried out after the extruder started skipping), the printer is absolutely stock, firmware and everything.
UPDATE: I've changed the factory hot end bloc with a brand new one, changed PTFE tubing one again, making sure it's as close as possible to the nozzle (unscrew nozzle 1/2 turn, fit PTFE, screw nozzle in) but it didn't change anything at all.
The extruder still skips steps as it can't push the filament out of the nozzle. Pushing it manually feels nice and smooth until it hits the nozzle, where I can feel too much resistance.
UPDATE 2: I've modifed the following parameters on the EEPROM to limit the filament flow:
M203 Z5.00 E25.00
M201 E1000

I've also crancked the temperature up to 220°C but it made no difference whatsoever. What I've noticed is that, after cleaning hot end and tubing, it starts skipping after 1 hour of printing, every single time without fail.
UPDATE 3: I've checked the input voltage from the PSU and it's 24V; the Vref for the extruder is 0.744V, so everything looks as expected.
UPDATE 4: The extruder idler pulley has a compression washer to hold it in place without impeding idle spinning; it is usually mounted in the order idler pulley, compression washer and bolt. I've noticed that the pulley wasn't spinning freely this way, so I inverted the order to compression washer, idler pulley and bolt. The bolt head is small enough not to stop the pulley from spinning.
I've also increased the pressure the spring arm excise on the idler pulley, so that the toothed pulley grips more firmly on the filament.
This way I've managed to improve things although not solve them. It's been printing for the last 3 and a half hour without skipping but it's not a solution, as the toothed gear is chewing too aggressively on the filament. In just one hour a good deposit of PLA shavings has formed on the extruder, and I had to blow it away, and this never happened before this all started.

To exclude the hot/cold end I would disable preventing cold extrusion (M302 S0) and disconnect the Bowden at the cold end and extrude, does it still skip? Also, look at the other side, is unspooling creating more friction?

Can you elaborate on "Replaced the whole extruder system (except for the extruder motor) with a metal Creality system." ?

@0scar Sorry I forgot to mention it, I did that yesterday and the filament extrudes without much problems so no skipping there. The spool is nicely spooled, so it's unraveling (is that a word?) nicely and without much resistance.

@R..GitHubSTOPHELPINGICE The grey parts in this picture are made of aluminum, and I've changed them from the plastic ones installed by factory. They didn't help.
Would a direct drive system help in this case?

Update: I've changed the factory hot end bloc with a brand new one, changed PTFE tubing one again, making sure it's as close as possible to the nozzle (unscrew nozzle 1/2 turn, fit PTFE, screw nozzle in) but it didn't change anything at all. The extruder still skips steps as it can't push the filament out of the nozzle. Pushing it manually feels nice and smooth until it hits the nozzle, where I can feel too much resistance.

I think you've learned that the issue is not related to the tubing and hotend. I would look into you stepper driver, I don't know if you can increase the Vref of the driver to allow more current through the stepper.

@vale.maio2: Randomly replacing parts with aftermarket ones is not how you solve a problem with your printer not working, so no. There are pros and cons of switching to a direct drive extruder but "not having a direct drive extruder" is not your problem.

@0scar It seems that the stock Ender 3 board allows for Vref adjustment, so I'll check that and I'll report back.

@0scar I've checked the input voltage from the PSU and it's 24V; the Vref for the extruder is 0.744V, so everything looks as expected.

So, after some day of yelling and disassembling, I figured out what was the issue. As many were suggesting, I indeed had an issue with the tubing lifting from the nozzle. it was lifting, so PLA was slowly infiltrating where it wasn't supposed to be to the point it created a blockage, resulting in skipping.
However, no amount of cleaning and reseating the tubing got rid of it. i've also changed, again, nozzle, tubing and pneumatic fittings to higher quality ones to no avail.
I got absolutely fed up and bought a direct drive conversion kit. One of the cheap ones, reusing most of the stock hardware, including stock extruder and gears. The idea, for me, behind it was that the mass of the extruder, and the much shorter length of tubing, meant that the tubing had no space to move around and let the PLA out.
It looks like it's working so far, I'm 6 hours in on a 10 hours print with no skipping at all. I also managed to ease the pressure that the extruder arm excise on the filament, so it's not being chewed anymore and I'm not seeing any PLA shavings so far.

So it was basically what I said...

I'm pretty sure CHEP has a good video or two on dealing with this problem if you have it. It's certainly not a reason to change to a direct drive extruder unless that makes sense for you for other reasons.

Those would be https://www.youtube.com/watch?v=7tCxO17XZtw and https://www.youtube.com/watch?v=Fb4XMbZ0iA4. But I think as long as your bowden tube is cut right, not damaged from wear/heat, and properly inserted, you don't need any of this. You just need to make sure it's installed far enough down to butt up tightly with the nozzle. Unscrew the nozzle a bit while inserting it to let the tube go down farther, then tighten the nozzle back against it.

@R..GitHubSTOPHELPINGICE Yes it's exactly what you said but, even after following ALL of those steps, multiple times, I still had the same issue, over and over again. As I said, the weight of the whole direct drive system now keeps the short piece of tubing in place.

This is a very common problem with bowden systems in general, and Ender 3s in particular.  Mine underextruded from the day I bought it, until I pulled out the tube and re-cut it flat, broke two couplers trying to squeeze it in enough to prevent gaps and finally got it working.  That lasted a few months before oozing again, so I gave up and switched to a direct drive system, too.  Probably the same one you have.  Zero problems since.

In case anyone else also runs into this problem and has tried everything above, here is how you fix it for good.
While the direct drive extruder might work, it may seem odd to some that the system that previously worked fine now doesn't and needs a complete rebuild.
The problem is caused by a faulty cooling fan for the heat sink. Replace the AXIAL fan on the hotend. That is not the radial fan that is used to cool the print.
The devious thing about this problem is that the symptoms occur seemingly randomly which is caused by the rather slow heat transfer in the heat sink. At some point during the print a critical temperature is reached which deforms/lengthens the heat sink and opens up gaps in the path of the filament. Those gaps cause the filament to get stuck.
The other devious thing is that the cooling fan appears to be working alright but is not. I assume the rotational speed is lower than would be necessary but that can not be verified with the means currently at my disposal.

Welcome to 3D Printing SE and thank you for your contribution. When you get a chance, please take the [tour] to understand how the site works and how it is different than others.

This was exactly it for me.  I was tearing my hair out! I replaced the extruder, stepper, filament, bought a filament dryer, the whole nine. I never would've expected that it was due to my hotend fan underperforming! I replaced it and instantly everything works.

I had the exact same issue and then suddenly it went away.
The only thing I had changed was my Z-offset. I moved it away from the plate by roughly 0.1 mm. To confirm it was the reason I set it back closer to the plate and the problem came back. I think When the nozzle is too close to the plate the plastic cannot freely flow out and hence the pressure develops at the feeder and it skips. This worked for me, everything is stock and no changes to the feeder settings or anything else.

Since you've said you can feel a problem at the nozzle pushing it through manually, and since you say it goes away for a while after cleaning, you probably have somewhere that molten filament is getting into that it's not supposed to, then solidifying and jamming. Check that the cooling fan for the heatsink on the coldend is working, and that the PTFE tube is properly installed all the way through the heat break and butted up against the nozzle with no gaps or irregularities, and that the pressure fitting is holding it firmly and not allowing it to back out. If you can't find anything wrong, it's possible that something is just defective/damaged inside the hotend assembly.

Unfortunately I've checked all of that. The PTFE tubing is all the way in touching the nozzle, and the pneumatic fittings do a good job holding it in place, as the tubiing does not move back and forth even when I try to move it. Since I've just replaced the whole hotend asembly I'm not sure what could be wrong still with it, unless I've been very unlucky and got a second defective hotend.

When you say you can feel a problem trying to push it through, do you still get it to extrude ok (with manual pressure)? Can you pull it back easily?

I can get it to extrude manually, even when the extruder stops, well, extruding. I wouldn't say easily as it takes a considerable amount of force.

Lot's of factors can cause this behaviour. Firstly check there are no knots in the reel - that can lead to the reel locking up. Second check the PLA temperature and if dual wall (a lot of material being put out) check that the print head is not knocking (running over the top of) excess material due to oozing. I found that after swapping out the print head HE and extruder for new, that the root cause was that I had oozing and was not using the nozzle fan. This led to the head bumping over lumps in longitudinal runs (you could hear a thud), which led to the head getting gradually backed up and the reservoir in the head back-filling with hot PLA. This then created back-pressure into the Bowden tube and then up to the extruder, which is trying to push material into an already full reservoir (head + Bowden). And.. that leads to the cog wheel in the extruder fighting against the pent up flow in the HE. The solution was to put the fan on and that stopped the ooze blobs. Because I had elected to print a fairly heavy object, the wall count was causing an excess build up and my extra-prime setting, although good for thin wall printing, together with the 6mm retract, wasn't right for thick-wall printing. So I could have turned down the extra-prime a bit, but the nozzle fan was the best and easiest option. You have to think about the whole material flow process and how the system is wired: flow-wise. It's a fancy glue gun when you think about it. So you have to be mindful of all of the parameters that can affect material flow.
Having replaced the HE was actually a good idea, as I can now easily prime the head just by pushing material through by hand and feeling the flow. If you are having to push really hard, that means there is a blockage: either the head, or in the tubing or reservoir. Every two months you should maintain the printer and make sure that the head is running clear. The Bowden can also start to restrict in the head where the cleat locks onto the tubing. Heat, plus continual flexing leads to the tube starting to kink. If you are getting flakes at the extruder gear mechanism, then you have a Bowden tube or HE issue. Pushing the PLA by hand will tell you that. After a new HE is put in, you can feel the difference. A Creality 3D Pro head assembly is a few quid. I would suggest keeping a spare set of parts for maintenance work on-hand.
Flakes at the extruder could also be a sure sign of water ingress in the PLA. Look for small warts or bubbles in the print. If so, put the reel in an oven at at 60 °C for about 10-15 minutes. Then let cool off. Ideally you need a dry room to store reels, or a proper bucket with a drying agent inside. In the summer as heat and humidity rises, you'll notice that there's more absorption of water. If your printer is in the same room as a washing machine/dryer, you're asking for trouble. Ideally you need a dry cool space. Or just print a huge batch off and get through the reel quickly...

I my case helps reducing printing speed, from 100% to 80%.
Looks like the filament is cooling noozle to fast.
In some large prints at the begining (on first layers) I'm reducing speed to 60%.
This looks like the background temperature is not the same in the center and at the borders.

i've expirenced this a few times and just using my expirence from machining i narrowed it down to a few factors that changing fixed. #1 hot end temp, #2 axis speed, #3 filament feed rate. by playing with these settings i tend to find a happy medium with what im printing. it takes running a few set up pieces but with trial and error you can find a working point for your machine vs recommended settings. no two printers are ever the same just like no two CNC centers are ever the same. the jamming of the extruder usually is feeding too much material into the unit for its temp or it gettinng clogged at points by a bad bed level. If prints still come out ok, its pushing too much in IMO.


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Strange stringing-like activity when printing face shields
I'm printing stacked Prusa COVID-19 face shields on a modded Ender 3. It works fairly well until the second layer of masks, where we get this weird effect that's kind of like stringing. It looks like the curve is becoming "low poly." I'm sorry that I can't be more specific, but I really don't know how to describe it more than this. Please look at the pictures to get more info.
One of the strangest things is that it worked earlier with the same slicer and the same profile. I am using PrusaSlicer, but I tried it with Cura and it still didn't work. There are a few more problems with the prints: some under-extrusion on the supports, and some spots had little gaps between the layers.
Does anyone have any fixes for any of these problems? I would mainly like to know about the strange kind of stringing because that actually prevents me from stacking prints.
I am printing Overture PETG at 240 on the nozzle and 80 on the bed. This is at a speed of 50 mm per second. I have the Basaraba Innovations direct drive mod, the Creality silent board with TH3D Unified Firmware based on Marlin 1.1.9, and the EZABL Pro.
Please look at the pictures to see what is happening.

It turns out that the brand of PETG that I was using was not good for stacking prints. I tried another brand of PETG and it worked perfectly. Thank you for all of the suggestions of what could be the problem. If you are stacking face shields (or any other print), do not use Overture PETG.

This isn't stringing. It's failure to adhere to the previous layer, so tension in the newly extruded material just makes it form a straight line until it bonds to something again. Are you used to printing PETG? You didn't mention fan settings, but having any cooling fan at all will cause failure of layers to bond. Your print speed is borderline for PETG, especially if you're using thick layers like 0.3 mm which you also didn't mention but looks like might be the case.

Yes, I am using PETG at 40% fan speed. I am also using .24 mm layer heights. I will try printing with no fan and see how that goes. Thank you!

.24 at 50 mm/s is probably a higher volumetric rate than your hotend can keep up with for PETG.

So what speed and layer height do you recommend?

My profile for PETG is mostly 40 mm/s except 45 for top/bottom layers, at 0.2 mm layer height. This is for use on an Ender 3 with stock hotend. I had a really hard time not getting sporadic underextrusion and poor layer bonding with anything faster. Supposedly PETG actually likes thick layers though so you might do better keeping 0.24 layer height and scaling down speed proportionally (33 mm/s). Aside from letting the hotend keep up with the needed melt rate, going slower keeps the heat over the newly extruded material longer.

I tried these things, and I got no underextrusion, but there was still the bad layer bonding between the 1st and 2nd layers of masks. The bad layer bonding is only happening on the part of the mask that is touching your forehead, if that is any help.

If the new problem doesn't seem the same as the original one, maybe a new question (with reference to this one) and new pictures of what's going on would be useful. FWIW I find PETG really annoying to try to print with.

No, it is the same problem as before. I might just try printing these in PLA and see if that works.


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How to I assign an imported STl file to a variable, polygon, or otherwise manipulate it?
I have 2 STL files that I want to chop, rotate, and glue together.  If I printed them and literally chopped and glued them together, I would be done.  Very simple operations.
I imported them both into OpenSCAD, but I can't find docs or figure out a way to do anything to the STL files once they are imported.  They imported fine.  I don't know how to assign a variable name to the imported object, which I presume is the next step before I can rotate and move the objects around.  I might be going in the wrong direction though, I don't know.  usually during an import of a module you can assign a variable name, or instantiate it.  Since the import also instantiates it, I'm at a loss for what to do next.  I've programmed in a smattering of languages, but haven't touched OpenSCAD in ~3+ years.
When searching, I find a cornucopia of slightly related information like how to import a file from 2011, but nothing about how to work with it once it's been imported.

One can create a module to import the respective STL files.

module bring_it_on_1() {
import("c:/user/models/egg_on_face.stl");
}
translate([-10, 20, 0])
bring_it_on_1();

Other modifiers can be used and will act on the STL file appropriately.

The OpenSCAD forum has a discussion regarding this topic: http://forum.openscad.org/Working-with-imported-STLs-td23840.html which includes a link to a program to convert STL to OpenSCAD, which may reduce or eliminate the problem you experience.


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Can I print directly onto the bed plate? (Ender 3 Pro)
I just got an Ender 3 Pro at the beginning of the week and have been printing a lot. I creased the magnetic plate cover, not realizing how it would hold up to being bent. This led to uneven printing and nozzle issues, so I stopped using it.
Is there any problem with printing directly onto the platform itself, without a cover?

I've printed for several years direct onto the 3 mm heated bed of the Anet A8 I used; worked perfectly! I did use a specific 3D print spray for adhesion, see e.g. this answer on "Should you use hairspray on a metal bed 3D printer?".

I'm super new to this, so just for clarification- The overlay that came with the printer and the glass bed upgrades are used for adhesion and removal purposes, but if I spray hair spray onto the original bed then I can print on it? What if I don't have hair spray? I'm using PLA.

Worked great! Tyvm. If you could still please clarify the purpose of the overlays (magnetic, glass, PEI, etc.), I'd appreciate it.

@Shades The magnetic bed is flexible, so you can bend to pop the print of. Glass and Buildtak are used for adhesion without the need to use a glue or spray, but sometimes, they also benefit from an additional adhesive. PEI fuses with PETG, so that didn't work well for me.


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Looking for files for printed parts for my Kossel XL kit from Builda3Dprinter.eu
A couple years back I received a Kossel XL kit from builda3dprinter.eu as a gift, but I stopped building it because multiple parts were missing, including printed parts. Now that I'm building a Prusa MK3S, I'm considering buying some of the parts and finding the stl files to print the printed parts. However I'm having a bit of trouble finding the files for the exact model, and finding the printed parts for the XL, rather than the mini. Any help would be greatly appreciated, and advice from people who built the same printer would be incredible. Thanks!

I bought 2 of these kits 4 years ago, and I have been really pleased with the quality of the kits and the results.  Sadly this supplier is no longer trading, as he could not compete with low cost imports from the far east.
I have the STL files for the printer kit, so you should be able to print any parts you need.
I have created a Github repository with a ZIP file of the parts files I downloaded from the builda3dprinter.eu website.


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Measuring the legs of the triangle instead of the hypotenuse in Fusion 360 sketch
When creating a sketch in Fusion 360, when drawing lines at an angle, it shows the length of the line:

The hand-drawn portion of your sketch shows the height, not the base. You currently do not have a defined base in the drawing. If one presumes to create a right triangle from the apex of the 13.9 mm line, you can use a construction line, which will provide a dimension, but still not the base. It appears you currently have a line for the base but not of the proper length.

@fred_dot_u: I don't follow to be honest. I want the green length to be 10mm. I guess I can do it with a construction line, but is it possible without?

Easy, place a point somewhere, press "d" for dimension and click point and than "your long base" and set it to 10; now draw a line between the point and the end point of the base. But, that is pretty useless, you also need to know the distance from the Y-axis. Why not sketch a rectangle of 10 high? Then you can draw the triangle in it.

So why do you want that value?  It's easily calculated since you know the line length and the angle.    You can calculate that value "offline" and then construct whatever other shape you want to add to the existing drawing.

@CarlWitthoft: I want to make the piece 5mm tall, with a 70 degree side of whatever length it is. So, calculating it is not what I'm after, but constraining it.

For this, use a construction line:

draw the approximate line
press x to go into the construction-line mode
pres l for the line tool
Draw a line from the end to the base
constrict it orthogonal to the base, turning it into the height
press d to go into defining distance mode
click on the dotted line
type in the height
press x again to get back to normal lines.
complete the triangle


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PID tuning 50 W cartridge in Marlin
Recently I decided to upgrade my Geeetech A10 (GT2560 v3.0 board) with E3D Chimera, Marlin 2.0.3 and more powerful 50 W heater cartridge. I wired everything up and tried to PID tune the hot end, but I got a problem.
When the tuning ends and I use the values with M301, the values are too agressive and the hot end initially overshoots more than 15 °C. After that the temperature is rock steady.

The tuned values are P=9.4 I=0.47 and D=46.4.
I tried to change the values according the wikipedia table to no overshoot (P=3,13 I=0.47 and D=123.7), but it just made the temperature unstable.
I also tried to tune the values manually but with no succes. I even tried to use zeros for all three gains but it just oscilated ±10 °C and still overshot.
My guess is that the cartridge is too powerful for the Marlin PID tuning.
Is there a setting in the firmware where I can set the PWM value for the PID tuning? To slow the heating down? I tried to use M301 E1 P0.25 S200 C10 but it seems that it didnt use the P parameter.
Or is there a way to manually tune the values without the printer? I've got an Arduin Uno and RPi Zero availible. Or do I have to buy another less powerful cartridge?

Just a thought, but if it's a 12 V heater then adding a 55 W car headlamp bulb in series with it would halve the voltage, quarter the power and give a visual indication of heater on. (Actual values will differ a bit due to the lower cold resistance of the lamp.) I did notice the power limiting setting in configuration.h while setting mine up recently but have little experience and didn't have a need to adjust it.

The whole system is running on 24V so I can't add typical car lightbulb. Btw I also checked the heater with multimeter and it has corresponding resistance (its not one for 12V).

In Marlin firmware the power to the heater cartridge can be limited by PID_MAX and/or BANG_MAX. What is the resistance of the heater cartridge? Sure it is not for 12 V, I recently experienced exactly the same problem.

You can de-turne the classic PID values to eliminate overshoot. See this RepRap Wiki article: https://reprap.org/wiki/PID_Tuning

@oscar I am sure that the cartridge is not 12V. The resistance of it when cold is 11,4 ohms and when hot 11,5 ohms. I found the PID_MAX setting asi you said, but I think it just limits the overall output of the cartridge, doesnt it? I might use it later, but right now I vould prefer to tune the PID values correctly, so I can use full potential.

@Mick Yes, I tried that. I checked the RepRap wiki and it is the same modification I did. Now I noticed that I wrote incorrect D gain into stack exchange after it. The correct Values after were P=3.13 I=0.47 D=123.7

Instead of one car bulb, put 2x21W in series, which are easy to find because it's what the combined position+brakes bulb use, and usually only the position light burns out.

Besides the P, I and D values, you may also have to tune PID_FUNCTIONAL_RANGE and PID_INTEGRAL_DRIVE_MAX.
Basically, the functional range disables PID control when more than the set number of degrees away from the target temperature and just puts the heater to zero/maximum power. The integral drive max parameter limits the value of the integral term of the PID controller.
The RepRap wiki notes: (note this wiki is dated! some options might not be available)

In Marlin, the parameters that control and limit the PID controller can have more significant effects than the popular PID parameters. For example, PID_MAX and PID_FUNCTIONAL_RANGE, and PID_INTEGRAL_DRIVE_MAX can each have dramatic, unexpected effects on PID behavior. For instance, a too-large PID_MAX on a high-power heater can make autotuning impossible; a too-small PID_FUNCTIONAL_RANGE can cause odd reset behavior; a too large PID_FUNCTIONAL_RANGE can guarantee overshoot; and a too-small PID_INTEGRAL_DRIVE_MAX can cause droop.

My hunch is that the functional range may be too small; the PID doesn't kick in until close to the desired temperature at which point you will already have overshot the target (due to the high power heater and delay in the measurements). Once you've overshot the target temperature the integral term starts growing (negative) which causes the massive undershoot.

Yes, that was the problem. I changed the functional range from 10°C to 25°C (original + what it overshot), retuned the hot end and it just came to the desired temperature +-0,5°C.

I cannot find PID_INTEGRAL_DRIVE_MAX; has this parameter changed name or is it obsolete? It looks like the reprap wiki is not up to date.

Yes, apparently so. The current version of Marlin limits the Iterm so that it never becomes larger than necessary to achieve maximum output power, but there is no configuration option to adjust this.


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Getting the Turnigy Fabrikator Mini V2 to a usable state
I recently bought a second hand Turnigy Fabrikator Mini V2, which, as far as I can tell, is a rebrand of the Malyan M100. After my first few prints I noticed that my prints were very stringy and the filament really didn't want to stick to the bed.
I asked a guy who has quite a bit of experience with 3D printing what could be the problem. He took a look at my benchy print and said it was way too light for a benchy and recommended I'd look at my feedrate (I think the setting is called).
So, in repetier host, I told the printer to extrude 50 (I am assuming this is mm, this interface is a little wierd), I am also assuming that this number is the amount of fillament going into the printer, not the amount that comes out of the nozzle. So, I measured that, and it did seem that the amount of fillament going into the printer in was definately a lot less than 50 mm.
As far as I understand this is a setting in the EEPROM. So, I connected to it using minicom (generic USB commandline interface) and sent the command M503, and after doing that, I got a bunch of settings in my terminal (formatting was a mess though and I am not sure if it was complete). After sending this command a second time, nothing happened and after a lot of disconnecting and connecting of the USB cable I figured out that this works only sometimes. I can't figure out how to get it to work consistently (G28 to home the printer always just works though).
I also tried connecting to the printer with other applications like for example Pronterface, but I haven't had any success with anything except for Repetier-host on Windows (I usually use Linux).
So then because I'd like to be able to change EEPROM settings and because I'd like to interface with the printer on Linux I decided that it might be a good idea to update the firmware. So, as a first step, I want to know what firware it is currently running. I couldn't find much information on the Malyan website, (I found a firmware download button that returned a 404) and I also couldn't find much on HobbyKing (the website that used to sell this printer). So, then I tried to send it the M115 command, and yet again, I got nothing back from the printer (I don't know if I never get a response or if I'd get something back after a hundred attempts).
So, now my questions are: what do I do from here? Do I just assume my printer uses some version of Marlin? I remember hearing that a lot of manifacturers just grab off the shelf open source firmware. Is there any way I could get a clue about what it is running? I know there is an stm32 on the pcb so that may be a hint.
Could I put something like Marlin on it even if it wasn't running that initially? is that even a good idea? I am assuming I'd at least have to tell it the pin mapping.
Here are images of 2 of the benchy's I printed. I stopped one of them half way through. The other one was my first print and the print speed was way too fast. I also did another print with slower settings but I can't find that one right now (that one was kinda stringy).

As a clarification of my question. As far as I know I have an under extrusion problem, and this is a problem that should (as far as I know) be fixed by changing the extrusion rate in firmware. My problem is that I don't know how to change this setting as I don't even know what firmware it is running. On top of this, when I try sending commands like M503 I get really inconsistent responses. I came to the conclusion of putting new firmware on it because I can think of no other way to fix this problem.
The right question here is probably: how do I change the extrusion rate in the firmware of this specific printer. (Any other solutions are welcome too of course. I have thought about just telling the slicer to compensate in the other direction but as far as I've read it is generally not a good solution to just say in your G-code to compensate for the under extrusion)
So, today I did a lot of testing. And I concluded that when I just insert some fillament into the printer and it hasn't reached the nozzle yet, it extrudes the right amount, but when it reaches the nozzle it just extrudes a lot less. So it seems to be a mechanical problem. I can change the extrusion command to actual extrusion ratio by extruding slower or by increasing the heat of the nozzle. But I have to go quite slow G1 F50 E50 to get anywhere near the right amount of extrusion (still a little more than half a cm short in this case). I did some test prints and it definately seems to make a difference to print slower. These cubes were printed with the one on the right being printed at a little less than half the speed as the one on the right.

I guess it has come to troubleshooting the actual physical extruder (or is this stuff normal and am I just supposed to print at slow speeds on this printer).
The printer is using one of those extruders where the fillament is fed into a tube leading to the nozzle.

The round thingey seems to be turning but it doesn't seem to grip the fillament well enough.

Welcome to 3dPrinting.SE! I'd welcome seeing the Benchy, as this could help us help you tremendously.

There are multiple questions in your question, basically you direct the question to updating the firmware while you actually have a working printer when dialed in properly! This should be fixable without having to flash new firmware.

Nice update! Does the stepper motor of the extruder have a flat surface on the shaft? The photo does not seem to show that. The extruder gear grub screw needs to grip on the flat spot of the shaft. If it does, make sure the spring exerts enough pressure, possibly increase the spring tension.

As there are multiple questions, I'm focusing on the actual problem that causes the Benchy print results (getting it to stick or firmware will not be answered).
Note that a Benchy is a nice, well known print, it actually isn't a good example to calibrate the printer; it is preferred to print calibration cubes, preferably the ones with embossed X, Y and Z.
Under extrusion is usually a result of incorrect hardware/firmware setup or a slicer error. It can also be blockage, but then the extruder needs to skip filament once in a while.
The prints show severe under extrusion. Note that 50 (in the slicer, extrusion rate) means 50 %, this should be 100 %. Basically, you tell the printer that it may only use half the amount of filament it needs to print the object. Furthermore, when you command 100 mm to be extruded, the actual displacement of filament also need to be 100 mm. See "How do I calibrate the extruder of my printer?".
If you really commanded an extrusion of 50 mm (e.g. G1 F250 E50, first reset the length with G92 E0), the amount of filament that is extruded should be exactly 50 mm. If the extruded length is incorrect, the steps/mm in your firmware is incorrect. You can look them up (or change them) with G-code M92.
Please measure your filament diameter at several positions and if it is consistently different from 1.75 mm update the value in your slicer with the mean value.

A very common mistake for people using Cura for the first time is that the Cura default filament diameter is 2.85 mm, not 1.75 mm. But, if you commanded the extrusion yourself with a G-code, it should exactly extrude that amount. If that works, but your print still are under extruded, look into your slicer options.

So, the reason why I didn't post a g-code command was because I didn't know the command, it was a button in a gui. Well, anyways, I did some more testing today and it seems that it does extrude the right amount, but that amount decreases by a lot when the fillament reaches the nozzle, so it seems to be a mechanical problem. I'll edit my original question with more details.

@TT-392 That makes sense now! Do you hear skipping noise? Does the filament go back? Please observe what happens and put that in the question. I'll change the answer.


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Ender 3 Pro Extruder Stepper Skipping with a Chunk sound
I have a relatively new Ender 3 Pro, stock except for adding a tempered glass bed. I've fed about 3 kg of PLA filament so far, all Solutech brand. Near the end of the last reel, I started hearing a chunk noise. It varies in rate, between several/minute to going 10-15 between chunks. This has continued into a brand new, just unsealed reel so I don't think it's associated with the filament.
I was able to finally discover that the sound is coming from the extruder stepper area and was able to see that when this happens, the filament drive wheel snaps back maybe 30-40 degrees. (This happens in the middle of printing a line, not when the filament retracts between lines.) I'm assuming that the stepper motor is slipping. There is no sign of gaps in the printed model nor is the filament on the reel binding that I can see.
I'm guessing maybe that the filament is being fed faster than the hot end can accept it, causing back pressure.
I'm using Cura 4.4.0 as my slicer the whole time and while I have changed some settings, everything associated with speed, feed rate, hot end temperature and such are all stock. I did not notice this happening until recently.
Has anyone seen this happen before? Anyone have any idea what could be causing this?

Does it happen at different coordinates or at the same spot of the bed every time? I had a similar issue because the bed was warped in one spot.

@Shades I don’t think it’s the same spot but not sure. Meanwhile, the issue seems to have gone away. The last few hours of the last job didn’t seem to have it happen.

I'd say it is time to check and clean the extruder. Maybe a loose screw, not enough tension, worn out gears, etc.

What hotend upgrade kit did you use as a replacement?

It wasn't a hot end but the extruder: https://smile.amazon.com/gp/product/B07NPLBBTW

UPDATE 3-May-2020: I have now confirmed that the problem was the extruder. Specifically, the input port which was causing the filament to bind. The front of the input port is a metal ring but the back is just plastic and and has worn from the PLA filament, as seen in this photo:

After some delay (see my other question here) I have installed the new, all-metal extruder (original stepper), the clacking is gone as well as the significant under-extrusion. (I also replaced the Bowden tube and print bed springs but I don't believe these were the problem).
Having seen what a few km of PLA did, I highly recommend upgrading the extruder.
Side point: immediately after the replacement, I started getting corners lifting off the bed which I hadn't seen before. I realized that the new drive gear was slightly smaller than the old so I checked the extruder calibration and it was about 10% low. I adjusted the extruder steps/mm from 93 to 99 to correct for this.

Original:
It appears the problem was the filament binding in the entry to the extruder assembly. I did start seeing signs of under extrudement such as the outer layer of a rectangular object separating of the rest of the body. Later, the problem became worse, with a lot of clanking, to the point that prints became quite fragile.
I have ordered a all-metal extruder assembly and will update as I get new results.
By the way, I'm really not sure why it's binding but running a strip of filament through the entrance hole, it sure seem to be binding. But in trying to disassemble the extruder and starting by removing the filament, I managed to get molten filament in the bowden tube. Without thinking about it, I pulled the blob all the way into the fitting for the extruder, plugging it so much that I cannot get the fitting off nor push it back into the tube. Anyway, I'm taking the opportunity to upgrade the extruder, tube and springs.


text:
Print failing at random, resulting in a "hairy" mess
TL;DR;
My initial answer fixed the problem for a while, but it still persists occurring... (see update 2 below)

Original question body:
Print fails at random resulting in a hairy mess although I:

cleaned bed,
added glue,
leveled bed,
tweaked temperatures and cooling,
cleaned nozzle,
tightened wheels, checked the axes,
tried to print temperature tower.

What else to do ?

First off, the equipment I use:

Printer: Artillery Sidewinder X1
Slicer: Cura
Filament: PLA

At first the prints came out as expected.

There is some bending at the bottom, that was later resolved by adding a brim. The object above and the ones later were printed with roughly the same settings:

Layer height: 0.28 mm
Wall line Count 3
Top/Bottom Layers 3
Infill 40% cubic
Printing temp. 205 °C
Bed temp. 60 °C
Print Speed 40 mm/s
Retraction on
100 % Fan speed
added Brim (after the first)

Yesterday that same part failed after 4 hours. I had to stop the print because the printer was making "a hairy mess" around the object.

As you can see there was some under extrusion earlier in the print which I didn't notice at first.
I thought the part came loose since it had little to none adhesion to the bed and after cleaning the bed properly and using some glue I started the print again. The result was the same, this time the print failed a bit earlier.

(The small part was printed on top of the loose mess before it failed completly)
This time the bottom was quite loose again. After that I decided to print some smaller parts and do some troubleshooting first. I noticed some weird looking "curly" lines right away and stopped the print. It looked like "under extrusion" and a "not properly leveled bed". (Notice that didn't happen in the prints before). So, after leveling the bed and printing the small part again the part got printed well until the top 3 layers which looked under extruded again and I could see the infill pattern through them.
I added 5 °C to the printing temperature and (the smaller parts had 30 % infill) upped the infill to 40 %. That didnt resolve the issue completly but the print looked well enough and I had another go at a slightly bigger print.
This time not quite as tall at the ones before and it failed again. The first hour or so everything looked fine, but the printer was getting quite noisy, every retraction was a very loud clicking sound the printer itself was shaking quite a bit during movement and the print failed again. This time the object was very firmly on the bed and I had to use some force to get it off.

The noise and shaking made me check the axis and tightened the wheels a little bit and after that I cleaned the nozzle with a "cold pull". The last thing I did was printing a temperature tower which failed in the same way and looks quite bad overall.

So my question is: Where do I go from here?  I'm quite new to 3D printing, there still seems to be some under extrusion going on, what are my next steps ?
Please note that it seems that the filament curls up at the tip of the nozzle randomly, resulting in a few lines not getting placed properly on the already printed parts. Eventuelly the print then fails. When I push filament throught it curls up and the stream is relatively thin. Not always though, most of the time it looks fine maybe a bit thin.
Can that be a clogged nozzle if X layers get printed ok, then for 5 seconds it messes up and then prints okay again?
[Update]
After changing the nozzle the filament stopped curling up and the lines look much, much better. But the problem persists. I started 2 prints, both failed a couple of minutes in. The second one on the first layer. It seems that the nozzle picked the just printed lines up.

[UPDATE 2]
Back to square 1. It seems that I fixed a problem that I created while trying to fix the original problem.
After 4 successful prints and ~20 hours of printing the last print failed in the exact same way as shown in the pictures above. The filament is curling up at the nozzle again. The heatblock is not leaking.

new heatblock
new heatbreak
new nozzle
new tubing between nozzle and idler
old filament
old print profile, settings

I guess the nozzle is clogged ?! Can that be after such short printing times ? I dont want to clean everything for 2 hours after every print. Or worse change everything out after 15 hours or so.

To me it looks if you have several issues, one being not using support for the top flat surface (I cannot see the object you are trying to print, but this might be a bridging or lack of support issue). This is apart from the under extrusion issue.

The gap at the top is 20 mm wides and 100 mm high and did print well in the 3 prints before. Could the poor overhang quality at the top of the drill holes and the overall bad print of the temp tower  be a result of under extrusion as well ? I did fiddle with the  screw that regulates the pressure of the filament erntering the extruder (don't know how it's called) after reading several times that it should be loosened if you see heavy "bite marks" on the filament - which i did. I think that was before the print quality got worse. Will do some more thests tonight.

have you cleaned your nozzle lately?

I did a cold pull. When i have time after work i will check the nozzle again and try another print - Although the printer is just 2 weeks old and i printed 500 g  - tops - of new PLA with it. Seems weird to me that the nozzle is clogged up that fast

In your second picture(only the second picture), it seems the layer had shifted all of a sudden. This happens when it lost power to the hardware but the mainboard has power the whole time. Means mainboard still got the power to run the program and give Gcode instructions. But no power to other components for a brief moment. Can you tell what exactly happens when shifting the layer..?

clogging can appear if you print too hot from cooking the filament, it can be contaminated filament coming in - dust clinging to the filament can be a PITA, which is why I store my filament in a dry box even if PLA doesn't actually need it in my workshop - to keep the dust off. It could also be a nozzle damaged during homing. Carefully observe your homing procedure that the nozzle never makes contact during it to avoid the later.

To help in troubleshooting it would REALLY help to know your printer though: please tell us the model and show a photo of the extrusion mechanism, because  I suspect the culprit here. Your recent rebuild hopefully made sure that all parts are in working order.

As  mentioned at the top of the question I am using the Artillery Sidewinder X1. I cant show an image atm, i am currrently at work

How much is the retraction (in mm)? The Cura default is 6.5 mm which is way too long for a direct extruder.

If i remember correctly it was originally 2.0 mm but i reduced it down to 1.6  mm for the last 5+ prints

I'm not sure if this is relevant, but 100% fan seems unnecessary on PLA, especially below 220°C. Is the driving gear clean?

After I finally had the time to disassemble the extruder and I found a possible culprit - which did solve the issue for some time.

As you can see on the pictures the heater block leaked and this lead to some filament dripping off of the side and onto the print. The nozzle then eventually caught these drips and this caused the mess.
Here are some tipps for beginners like me:

How to disassemble the extruder on the Sidewinder X1

Be carefull when trying to screw the nozzle out. You will most likely need some heat to soften up / melt the filament. I was not carefull and broke the thread. I then had to replace the whole heatblock.

Examine the tubing that leads the filament through the heatbreak and to the thread of the nozzle mine was a little bit deformed and didn't seem to be cut off straight to begin with.It has to be as flat as possible against the nozzle thread!

This was most likely the problem, Over time and after several melting ,hardening and melting procedures some filament creeped between the threads and the heatblock started to leak .. first slowly then worse and worse.
Hope that helps anyone. My prints come out great again. Plus I now know a lot more about my printer .
the original problem reappeared, see my update 2 of my question
[UPDATE]
Just to close this off: I can only guess what the original problem was but since I had this issue some times now I am quite certain, that it has to be bad filament (I am using really cheap one) and a relatively dusty environment, mixed with overreacting when trying to solve this issue. I got some needles with which I - fairly regularly - unclog / clean the nozzle especially after longer times without use.

Turned out this didnt solve the issue


text:
Ender 3 Pro prints leaning
Hello 3D printing experts...I am stuck on my 1st print not coming out right.  After two prints, I finally got the X axis belt tight enough to print the test pig and it came out quite well.  I tried to print a filter holder for a PPE mask (makethemasks dot com) - the prints keep leaning and I can't seem to get this filter holder printed.  I have adjusted the eSteps in various increments, still leaning.  I have made belt adjustments too.  I have emailed Creality as well since I have heard that their support might assist as well.  I was so excited when the pig finally printed properly and now I am struggling to get even once mask filter holder printed after hours of tinkering and reprinting.  I have also tried to print the ear saver (show as a long mass in the lower left corner of the photo), the base stuck to the item and I could not get it loose, it just fused together.  sigh.  I know 3D printing is supposed to be a fun hobby, but I am sure getting off to a rocky start.  I want to print PPE masks and be helpful to my community by donating to hospitals.  I hope one of the settings recommendations help.  I tried to research adjusting the jerk and acceleration settings.  Not sure what to set those to with the Ender 3 Pro.

Welsome to 3DPrinting.SE! To dial your printer in, you usually start by printing calibration prints, e.g. calibration cubes. It is difficult for others to comment on the printer if the basic working of the printer is not okay. Furthermore, what is the image trying to explain with the numbers? For us it is a guess how the square filter holders are oriented onto the build plate (e.g. Y from bottom to top and X from left to right?).

Along with what @0scar is stating, if you are using the gcode directly from the site, you might see if you can get the STL file and re-slice it using Cura (or one of the other slicers) which would be setup for your printer. If using pre-sliced gcode, the file itself may not be providing you exactly what you need and is what is causing the issues.

Without more information, this question cannot be answered. Please explain what the numbers are, what the orientation of the prints in the build surface was and what kind of basic settings you used to slice the models e.g. temperatures, speeds, see this question.

Steps-per-mm doesn't need to be adjusted, ever, unless you've made changes to the relevant mechanical parts. The values are determined by mechanical ratios. Extrusion amount will vary a bit by material because of compression of the material in the gear, but this is not a good reason to adjust esteps; just adjust flow % per material.

How did you print the mask inserts? Upright or flat (like laying now on the paper)?

This looks a lot like layer shifting, both gradual and sudden.  This is frequently caused by excessive friction on one axis, the one along which the print is leaning.  You mentioned tightening the X-axis; if these are leaning along the X axis, chances are good the belt is too tight and causing something (either the belt or the toothed gear it is attached to) to rub against something else (the frame, the v-slot extrusion, the motor itself in the case of the belt gear).
Both the X and Y axes should be fairly easy to move by hand with the power off.  Feel for any points where that isn't true.


text:
Why does PETG require slower speed?
PLA has a heat capacity of 1.8-2.1 J/g-K, while PETG 1.1-1.3 J/g-K. This means that each gram of PLA needs more energy to heat up. I assume no "melting latent energy", since we talk about plastics.
The density is about the same.
Still, printing speed for PETG is said to be kept at max at 60 mm/s, while PLA can easily go up to 100 mm/s.
Why is PETG supposed to be printed slower than PLA?
Edit: a link to a more recent question may be of interest: Power consumption of filament extrusion

Have you looked into the viscosity?

@0scar The only link I could find: https://www.researchgate.net/publication/334170527_Effect_of_printing_speed_on_thermal_and_mechanical_properties_of_rapid_prototyped_samples_for_shipping_packaging/figures?lo=1

@0scar but indeed PLA at 230°C seems less viscous than PETG at 255°C, judging by the oozing while I warm up the nozzle.

Isn't PETG significantly denser?

@R..GitHubSTOPHELPINGICE not really https://real-filament.com/datasheets/MSDS/EN/Real%20filament%20PLA.pdf https://real-filament.com/datasheets/MSDS/EN/Real%20filament%20PET-G.pdf

And just for fun,  try a test print or two to see if faster speeds w/ PETG lead to stringing, or gaps, etc.

@R..GitHubSTOPHELPINGICE   Density is irrelevant.  Liquid Hg is far denser than these plastics but has very low viscosity & will flow like crazy.

@CarlWitthoft: You have to scale J/g/K by g/mm³ to get J/mm³/K, the necessary melt rate relative to volume extruded. I think after that scaling PLA and PETG are very close, and the difference is then entirely other things like viscosity and layer bonding issues.

I'm adding this answer to somewhat challenge the findings of my original answer, and the premise of the question: PETG does not need lower print speeds, and can even be printed at higher speeds than PLA under some conditions due to reduced need for cooling. You can see this from some of the "#speedboatrace" entries printed with PETG. So what was really going on with the original claim and my agreement with it?
I think my original answer is still somewhat true: it's likely that it takes more hotend power to melt PETG at a rate that can be successfully extruded and bonded than to do the same for PLA. But there are other factors at play in the perception that "PETG has to be printed slow".
FarO did not specify details of the printer(s) in question, but I found the big limiting factor for my Ender 3 printing PETG was the stock extruder, which presumably was skipping bad to begin with, and even worse with Linear Advance, trying to keep the filament under high pressure to compensate for its compressibility. Since replacing the extruder with a direct drive one, I've had no problem printing PETG at the same speed as PLA, and both can print much faster than I ever could with the stock bowden extruder.

Link to the entries? I always see ABS, which is even faster to print

You may add a mention of the "melting index" and two TDS: https://polymaker.com/Download_File/TDS/PolyLite_PETG_TDS_V5.1.pdf and https://polymaker.com/Download_File/TDS/PolyLite_PLA_TDS_V5.1.pdf

Also, those TDS show a much smaller speed difference than I thought. You could mention it.

The density of PLA is around 1.25 g/cm³ and the density of PETG is around 1.38 g/cm³. When you're talking about the amount of energy needed to melt a particular volume (which is what your extrusion units are) rather than mass, you need to scale the heat capacities (with units of $\frac{\mathrm J}{\mathrm g\cdot \mathrm K}$) by the density to get $\frac{\mathrm J}{\mathrm{cm}^3\cdot \mathrm K}$. This brings their volumetric heat capacities somewhat closer: 2.25-2.63 vs 1.52-1.79 (about 47 % higher for PLA rather than your figure of about 62 %), but with PLA still higher.
You also have to account for heat loss to the environment. PLA is typically printed around 200 °C or 210 °C at most; PETG in my experience requires 250 °C to reach low enough viscosity to be printable at any speed. Assuming an ambient 20 °C, the rate of heat loss should be something like 25 % higher for PETG. So the hotend has that much additional energy needed to begin with.
Beside that, PLA is printed at temperatures where it's still extrudable and able to bond even if the temperature drops significantly below the nominal nozzle temperature (down to 180 °C, maybe even slightly lower), whereas PETG has trouble with increased viscosity and poor bonding right away if temperature drops.
Going broader still, PETG seems to need to keep its heat longer after being extruded in order for layers to bond well. (As evidenced by the need to lower fan or turn it off completely.) A slow-moving nozzle both provides heat (from the proximity of the nozzle itself) to slow the cooling, and reduces air flow across the part (by not causing as much air flow itself just by moving).

Given the values you calculated, and assuming 25->250°C for PETG, 25->225°C for PLA, you can also calculate the maximum flowrate: 0.02 mm^3/s every 10 W of heater cartridge for PLA and 0.031 mm^3/s per 10 W of heating cartridge for PETG. Hotends usually have around 30 W, which would result in 0.06 mm^3/s PLA and 0.94 mm^3/s for PETG. This assuming that, reasonably, almost all the power goes to the filament. Somehow this doesn't match the experience, since I successfully print PLA at over 5 mm^3/s (60 mm/s * 0.6 mm * 0.2 mm).

I can post this as new question if you think it's worth

@FarO: "and 0.94 mm^3/s for PETG" is off by a factor of 10, but otherwise your calculations look right, and I'm not sure where the error is. A question on computing volumetric extrusion rate limits from hotend wattage would be interesting I think.

OK I'm dumb. Densities are g/cm³ not g/mm³.

Well I also didn't notice that. So it's 31 mm^3/s PLA per 10 W hotend and 94 mm^3/s PETG per 10 W hotend, minus losses. It would look like that viscosity is the main limiting factor in general, together with short permanence in the heater.

Where did you get 31 and 94? Looks like 20 and 31. I think you're also underestimating the contribution from heat loss to the environment. You can get an idea of the magnitude of this number by measuring the average power used by the printer to maintain hotend temperature without extruding anything.

Sorry I already multiplied by 3, for 30 W, plus a typo for PLA. Good suggestion about measuring no-extrusion power. However, due to PWM it's not so easy, power meters oscillate between minimum and full power.

@FarO: Right, 20 vs 31 (per 10W) or 60 vs 93 (for 30W). Not 31 vs 94. Re: PWM, you need to either measure the duty cycle or use a proper watt-hour meter rather than just an instantaneous reading.


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Prusa MK3S 0.8 mm nozzle layers separating
I am currently printing a simple cup out of PLA (I will later anneal it). My nozzle is 0.8 mm and I'm using a 0.4 mm layer height. Unfortunately, the layers keep separating. They don't detach completely, but there are 1 layer-tall, 3-7 mm wide gaps. I increased the temperature, since my speed is 100 mm/s. I also tried decreasing cooling and increasing the flow. This only helped a little bit.
Moreover, small increases in the temperature like 230/240 °C didn't work and now I have to use 270 and even 280 °C, which is crazy, considering my layer height is 0.4 mm. Is there any easy solution that will increase the quality?
Settings:

Material: PLA
Layer height: 0.4 mm
Nozzle: 235 °C first layer, 270 °C for the rest.
Bed: 60 °C
Cooling: 62 %
Speed: 100 mm/s

I have noticed that 280 °C is better for large prints (large area, not height) and small prints look better when I change the temperature to 240/250 °C.
This is how my prints look by now. The extrusion is very inconsistent, with overextrusion in the middle of the layers and gaps in the corners:

I suspect that the layer lines are not parallel to the heatbed and are over extruded, because of the high temp. I lowered it to 230 °C and there was no drooping/over extrusion, but there were more 'holes'.

Is it possible that your hotend cannot keep up with the flow? Hence the large temperature?

The hotend is the default one that comes with Prusa MK3S. I don't know how powerful it is and I don't know how to check if that's the case. My flow is around 100 now.

Just for troubleshooting, have you tried printing more slowly?

Wow, that is smoking hot for PLA ...

@Aerik I have and it did help. I reduced the speed to 50mm/s and the result was better, but I still think it's too slow. I know someone who could do 100mm/s on the same printer, nozzle and layer height . I saw that a long time ago so I still have no idea how he pulled it off. Also, I changed the nozzle so as to print faster and it turns out that 0.4mm layer height at 50mm/s is far slower than for example 0.3mm at 150mm/s

Large nozzles can make larger heights but need to be done slower unless you have a more powerful heater or longer meltzone.

How about you swap in a 0.4 nozzle and see how well the print comes out -- and how long it takes.

@CarlWitthoft I've been using the 0.4mm nozzle for a long time now and the print quality is really nice (on the 0.4mm nozzle). I printed a different version of the current model on 0.3mm layer height and 150mm/s speed and it was really nice. I changed the nozzle for two reasons: faster printng and food safety (brass nozzles have lead, hardened steel ones don't) Unfortunately, I have just run into another problem. I'm getting the THERMAL RUNAWAY error, because my nozzle temp. drops from 280C to 230C. What's the cause of that?

Edit: I fixed the THERMAL RUNAWAY error by placing a small E3D silicon part that protects my nozzle&hotend from excessive cooling caused by the part cooling fan.

After printing ~30 calibration test cubes I finally figured out the perfect settings.

Apparently, the extrusion width in my slicer was set to a certain number, instead of
percentage. I was printing at 0.45 mm extrusion width, which was ~105 % of the 0.4 mm nozzle diameter, but less than 50 % of the 0.8 mm one. Changing the value to 130-140 %
solved the majority of my printing problems.

As I predicted, the 230-280 ℃ nozzle temp. was ridiculously high, even with the
0.8 mm nozzle.  I gradually lowered it to 210 ℃ (ironically, the value I chose at the very beginning).
 There was some warping, so I cleaned the heatbed from the glue, put the glue again and decreased bed temp. to 50 ℃
 Finally, I decreased the flow from 1.3 to 1.05 and everything seems perfect now.

Nice that you shared your solution, this was hard to guess based on your question! This proves that stating all the print settings is a must for solving print problems. Your small extrusion width in combination with the large flow modifier mimics the wider extrusion width, but fails to do a proper job. +1 from me! Note that I still find 100 mm/s to be fast for a 0.8 mm nozzle, but of it works, go for it!

@0scar Thank you! I found that larger prints required higher temperature/different settings, but luckily the most important part is done.


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Tarantula droplets on the side
I have add my Tevo Tarantula for a couple years now and made a lot of modifications. The last in date is a direct extruder from Trianglelab with an updated X-carriage and a NEMA 17 motor for the extruder. Without counting the number of times I clogged the extruder I managed to get some prints, some of them can be considered to be of "okay quality".
But each and every time I got the same problem, very irregular print sides (see photo attached). I could not find anyone with the same irregularities on their prints.
Indeed, instead of making thin line layers, the plastic is extruded in forms of droplets. Hence the side of my prints have these uneven sides. I could not find a pattern so far (only on one side, or in one particular orientation) and I am having a hard time figuring out what is the cause.
As a possible candidate I am considering a X-Y stepper calibration problems (which I would not know how to address) as when the printer is active instead of going smoothly during long travels some motors are going by noticeable steps (unsmooth steps). I am a bit puzzled since I installed Trianglelab smoothers a while back and my prints quality really improved at that time...
If anyone has an idea I am very keen to have some heads-up.

I have just finished my new print and please find the photos of my issues below. As you can see, there is a irregular side along the y-y axis. I usually saw problems from other people along the z-axis.
I have just launched a print with 110 % flow rate to see if I notice any difference. Now it’s on layer 2 and I still those little teeth on the side....

looks like either adhesion problems on the outline, shrinkage or underextrusion...

I am printing a new piece today with a perfect adhésion to the bed this time... I’ll show you the result in a few minutes.


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ETA for print job showing negative in Repetier host
I'm using Repetier host 1.0.6, and ever since adding default retraction settings, the "ETA" showing during a print job is negative:

It stays this way throughout the print job, which is no fun, since having a real ETA is super convenient.
Here are my retraction settings in Slic3r, for which I only changed length from zero to 5, and changed lift Z from zero to 2:

Why do I have a negative ETA value?

First thing:  revert these settings and see if the problem remains or not.   Second thing:  clearly you're printing with antimatter!  :-)


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Nozzle digging into print after filament change
So I recently watched a YouTube video on using Cura to modify a G-code to pause at a certain height in order to change filament (using an Ender 3 Pro) first time I did it, it worked fine but now when I replace the filament with the second colour and resume the print the nozzle digs into the print and tears it up its like it forgets it has done the first 5 layers and goes down to the bed again, the bed hasn't been moved neither has the Z-axis. can anyone help? It's beginning to do my head in I'm just wasting material.

Do you actually see it move down after the filament change? Or is it possible that it just moved down while paused/parked for filament change? If it really is moving after the resume, it could be that the Cura plugin you're using is buggy and puts something bogus in the gcode that causes it.

Once I change the filament and click resume it reheats the nozzle and then resumes printing but when it does it moves down and digs into the print and tears it like it's trying to do layer 6 at layer 1

Are the steppers powered during the pause? Are you pressing so hard that the X-Z gantry moved down?

How do i tell if the steppers are powered or not? And I'm very careful to not move the x-z gantry I gently replace the filament I've even measured the gap between the nozzle and bed before and after to make sure it hasn't moved

Sounds like the plugin put bad gcode in.

If the steppers are powered you cannot turn them, they are locked. Maybe you can post a part of the G-code file so we can see if the pause script works. Post the code, e.g 20 lines, around the pause.


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Poor adhesion on new layer - Monoprice mini select
On my Monoprice Mini Select v2 there is poor adhesion when the print head goes to put down a new layer on the bed as seen in the photo. Does anyone have a fix for this?

What is your first layer print speed? It seems to me like you're printing too fast and the filament hasn't enough time to settle on the bed.

I print super slow for the whole print since it seems like I get better detail this way

You could try a higher bed temp, but also check to make sure bed is levelled all round as this can sometimes cause this to happen

I’m pretty sure the bed is leveled but I’ll check it again. Would another surface like painters tape, or a glass bed upgrade help?

I find printing on glass bed with tape always gives a  better result but the build tech material is just as good it just needs regular cleaning after each print as oil from your fingers can get onto it and it rests on the top, looking at your image it seems to stick fine after that first bit, painters tape is OK but doesn't always work I use https://www.wanhaouk.com/products/wanhao-print-bed-tape

If you have already used alcohol to eliminate grease and fingerprints, sometimes scrubbing the print surface with a regular green scotchbrite pad can restore adhesion. It micro-scratches the surface and seriously increases the surface area of contact.
This all assumes you have properly calibrated the bed, reduced first layer print speed by at least 50%, increased first layer print thickness By >= 50%...

Things you need to check or do:

Use adhesion layers
Set lower speeds at first layer.
Increase bed temperature (try 5 degrees steps)
Clean the bed
Check if the bed is completely leveled up.
Increase the thickness of the first layer.


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How to check if filament sensor is ok?
The filament sensor of my i3 MK3 stopped working. In the support menu, it just says IR: N/A. This is the same output as if I disconnect the filament sensor.
My PCB says rev 0.2e and this is what I see:

In the Prusa Shop, I found a laser sensor, which has 4 pins, so that's probably what I have.

I have already checked the voltage coming from the Einsy cable. It's 5.02 V, which is probably ok. The remaining two pins seem to be SCL and SDA, so it's likely a I²C bus.
I have Arduinos, ESP8266 and ESP32 around. Is there a test routine that I could run on the filament sensor, other than Prusa's N/A display?

You could try out this Arduino sketch and see if the Arduino can find the sensor on the bus, but I'm fairly certain that the chip has developed a fault and stopped responding to I²C commands, hence the error, or it's giving a value that's outside the limits set in the firmware.
I'd also recommend getting in touch with Prusa Research, they have very good support and can tell you what part you need for your machine.