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Does updating the firmware on an Ender 3 V2 erase its previous settings?
A few months ago, I flashed my Ender 3 V2 with JyersUI fork of the Marlin firmware and I like the options and settings that are available with this firmware. The author has put out another update (v1.3.4) and was curious if all my settings will be erased.
Does flashing the firmware erase all settings on the Ender 3 V2? If so, what settings should I record to update the new firmware once installed?

No, settings are stored in memory (or the equivalent storage location).
When a new firmware is uploaded, the values set in the newly configured firmware can be set by Restore Defaults from the Marlin printer LCD the user interface. Alternatively, you could print a G-code file containing M502 and M500, or send them over using a console.

M502
Reset all configurable settings to their factory defaults.
To also reset settings in EEPROM, follow with M500.

M500
Save all configurable settings to EEPROM

See M502 will reset all configurable settings to their "factory defaults", which settings are those? for more information.
This answer hints to a similar description:

Installing firmware does not by itself alter the EEPROM, so these settings needed to be seeded into SRAM via M502 and then saved into EEPROM via M500.

Please note that the EEPROM on 32-bit boards are emulated. There are several ways to emulate EEPROM storage via flash storage in the ARM processor or using an SD card. There is a solution for an actual EEPROM, but that requires buying an EEPROM chip and breakout board on the I2C connector if it has such an output port. Selection of which is done in the Configuration_adv.h config file.

For verification of any changes, could I send an M503 to the printer before flashing the new firmware, save that to a .txt file, then flash the firmware, send another M503, save to another .txt file, and compare the two files for changes?


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Layers on printed part have started smushing together mid-print and I don’t know why
I’m using the Ender 3 with the Cura slicer and I’ve had success in doing the same print but recently the layers in the middle have smushed out and I don’t know the reason why.
I’ve tried reprinting the piece and the same problem occurs in the same area. I’ve yet to try to let the part finish because I don’t really want to waste filament so whenever I see the problem I stop the print.  I tried reslicing the part but the problem still happens.
Here’s the smushed print:

And here’s what it’s supposed to look like:

Edit: Should also mention that I’m fairly new to 3D printing

It looks like a problem with the Z axis. It looks like it isn’t lifting the Z as much as it thinks it is, so each layer gets over extruded because it’s trying to pack too much plastic in a shortened height. I would try cleaning and lubricating the Z rod(s) (with grease, not oil) and run the z axis up all the way and back down a few times, and watch for skipping steps or roughness in the travel.
Look for obstructions to the little wheels on the Z gantry as they roll up the frame posts. You could undo the Z gantry from the Z threaded rod. Be sure to support it on a box or something. Then lift the axis up and down by hand and feel if it’s smooth. A lot of problems with motion on 3D printer be revealed if you can work the motion by hand.

This issue appears to be in the first layers, so maybe z is starting too low.  .

@Perry, in the pictures you can see it starts fine, goes maybe 5mm then overextrudes.
I had the exact thing happen at a certain height, it was a fouled up bearing in the z axis, (linear rail with linear bearings on my machine) making the printer skip Z steps in the same spot.

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Inconsistent layer printing
I’ve had my 3D printer for about 2.5 years. Recently while I’ve been printing, it makes these small little gaps in the filament, like it can’t print consistently.

I’m not sure if there’s something wrong with my filament, or with the printer print. What do you think?

Have you changed your filament that you are using, or it is the same as you were using before this issue arose?

Hi Nathaniel, welcome to 3DPrinting.SE! Can you give some more information? E.g. has this happened suddenly, did you change slicer or version, have you cleaned the nozzle with a cold pull, what material are you printing, at which temperature and speeds, do you use retraction, how much, what hotend and printer do you have, etc. The more info the better people can help you! Look into this Meta question. Thanks.

Does the filament make popping sounds as it comes out of the nozzle? Has the filament been left out or kept in a ziplock bag or container?

@ChinchillaWafers
Not that I can hear, but it does look like there are air bubbles sometimes. And it has been left out before. Additionally on the last print I was trying to run, it stopped extruding all together

It’s a flashforge finder. Printing pla, 1.75 mm. I’ve tried temps between 200-210 C. I have changed filament, but it was working fine on this filament for a bit first. I have cleaned the nozzle, And when that didnt work I purchased and replaced it with a brand new one.
@Oscar

In my opinion, the shown error could have four possible reasons:

Your filament absorbed too much moisture between the prints. During your print the moisture will be released as "little steam bubbles" which make some popping noise. With certain filaments you can even see this if you look closely. Normally PLA should not be so critical as compared with PETG or NYLON for example. If you haven't already done so before, please change the filament spool to a completely new one that is still packed in vacuum. Hopefully this should already solve your problem.
A clogged extruder can also be a reason for inconsistency. But if this were the case, the extrusion would be significantly worse. So in your case I think this is not the main reason.
A bad filament diameter quality can also be a reason for an inconsistent extrusion. But the result should not look as bad as it looks in your picture. So I do not think it is very likely in your case.
In very rare cases the stepper driver or the extruder motor itself can also be a reason for bad extrusion. I had this once and after a change of the motor everything worked fine again. But this should be the last option after all other approaches failed.

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(SKR 1.4 Turbo, TMC2209 Drivers) - Power supply has 4 output, but board only 2 input
I have recently purchased an SKR 1.4 Turbo which I intend to add to my P3Steel printer. I have an old power supply which appears to have dual outputs [COM COM +V +V]. I want to connect this to the board but the board only has a +V -V connector. The supply is rated at 12 V 15 A which I believe is what is required by the board.
Do I have to connect both +V from the power supply to the +V on the board, and both COM (-V) on the power supply to the -V on the board?
I guess what I'm asking is whether the full 12 V 15 A is only achieved by using both of the outputs together?

Is this the manual to your board?
www.roboter-bausatz.de › pdf › BTT-SKR-V1-4-Instruction-Manual

This might give you some technical infomration: https://www.amazon.com/BIGTREETECH-Controller-Compatible-With12864LCD-5TMC2209/dp/B082QYYFVX/ref=pd_bxgy_img_1/140-1784107-2209361?pd_rd_w=rvqDY&pf_rd_p=c64372fa-c41c-422e-990d-9e034f73989b&pf_rd_r=CGXT19MHAGXCPEYRH1W6&pd_rd_r=08e69a2a-9f89-4de4-ab09-a61702d113d4&pd_rd_wg=OM6ih&pd_rd_i=B082QYYFVX&psc=1

It's possible the power supply has both force and sense lines. However, sense lines are usually marked S- and S+.

You'll be fine just using one of the "outputs" - in fact, they're connected right on the PCB, unlike the multiple +12V rails you may find on a computer PSU.
There is no benefit to running both leads, since the connector on the SKR 1.4 T would be the limiting component here.
If you're using an external MOSFET for the bed, you could (and should) use the second set of connectors though to keep wiring tighter and spread the load a bit.

My Ender 3 has the same connections on the power supply.  As received from the factory, the machine runs off one set (mainboard, bed heat, hotend, and fans) and the other set is left open (I think they're connected inside the power supply).  Given mine is a 300 W rated supply like yours, you should be okay drawing 15 A connected to either V+ and either COM terminal.


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Anycubic resin printer not printing beyond the first layer
I recently acquired a Anycubic Photon Zero and I'm having trouble printing anything that's not pre-loaded from that company.
I create my own models in Blender, put them through the Photon Workshop slicer software as well as download other models from the web for personal use and only the bottom or 1st layer will print! But anything that came pre-loaded as a demo from Anycubic prints fine.
Is there something I'm missing? What should I be checking for in the slicer software? Clearly the model is ready as you can see it all in light-blue on the printer/thumb drive, and as I said, it prints the first layer correctly.
I have calibrated the printer previously.
It's level, I even have a new resin resevoir with a clean film on the bottom.
What I noticed when I try to print vs what any cubic provides is, you know how the print head or plate moves up and down consistently. It almost seems any of these problem models, the printing plate stays in a static position for quite a while before it moves onto the next.
The screen shows what appears to be the correct layer being printed but I noticed even the plate doesn't move down back into the resin as it should.
Any thoughts? Thanks in advance.
Ps - I'm using I believe their brand resin, the plant-based one.

Although you've noted that you have run the model through the slicer, what's missing is if the preview shows you more than one layer. Near the bottom of your post, I think you're indicating that more than one layer is being displayed. In the preview, you should see images indicating that the layers are changing as the slider/progress bar is moved.
The first layers of a resin print are often tens of seconds long, to establish a more cured bond with the build plate. Depending on your settings this can be four to six layers running many seconds, but once "cleared" of the foundation, the duration should be shorter.
Consider to use a different slicer as a means of comparison. Also, consider to download an STL of any form from a different resource, something you have not created. Blender is known for creating unprintable models.
Additionally, you can save resin by not pouring any in the vat during these tests. If the characteristics are as you describe, you can examine the movement and the layer displays as the print job progresses, while not wasting product.

Thanks for the suggestions. Correct, in the slicer software it is showing the progress if I move the bar. I think that part is correct.
I'll try to create a file based off an STL not in Blender, or just get an STL from the web and give it a go. Yeah sometimes I try not pouring in as much resin - makes cleanup a bit quicker.


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Can you optimize head movements to speed up printing?
I'm currently printing 11 copies of the same model.  I noticed as it's printing that it seems to work on one model at a time but doesn't travel to the nearest model next.  I suspect it's traveling around the bed in the order that I put the models in the slicer.  This is resulting in extra unnecessary travel and therefore, increasing print time.  I slice in Cura 4.9.
Is there a slicer that handles this better? Or is there a way to optimize movements in Cura?

If you're handy with software, e.g. python, you could slice a single product, and insert code by a post processing application after each layer to add a travel movement and print that layer again with the offset given by the inserted travel, shouldn't be too much work. ;-) You do need to reset the extruder at every new product layer, in Cura you can insert a placeholder after each layer, there are plugins available.

It's well known in mathematical circles that the "salesman problem" is what mathematicians call "hard" -- in their usage, that means a lot of extremely smart people have worked on the problem for many years (more than a century?) and still not found a robust, works-every-time solution.
What's probably happening with Cura and other slicers is that, for their version of this issue (the most efficient way to visit multiple locations) the decision was made that reducing computing time in slicing was more practical than optimizing travel time of the machine.  This is a reasonable decision, from a programming standpoint, because you're likely to be sitting in front of a screen, getting more and more impatient (and thinking less and less of the software you're using) every second the slicing takes, but when the actual printing is going on, you can be doing something else (sleeping, working at your day job, etc.)
Therefor, it's likely that what you see in Cura is optimized -- to minimize your time on the way to a solution, rather than to minimize the time for a machine that simply doesn't care if a print takes five hours or nine.

Long story short: I only know the setting "Combing Mode OFF" that improves the travel paths. In my case it did not help. In your case I suggest you should give PrusaSlicer a try. I assume that the overall print duration will be improved because of a better calculation of the travel paths. But this is only my personal opinion between these two Slicers.
Further explanation: I downloaded the Cura 4.9 and made an install from scratch. I tried to reproduce your issue by placing lots of copies of the same part. As printer I selected the Ultimaker S5 and used the standard configuration for slicing. I let Cura arrange the parts on the print plate.
I checked the travel paths between the parts and in most cases Cura has chosen the nearest distance to move the printhead to the next part. In my opinion, there could be a more efficient choice for the next part to print.
After this first test I experimented with the settings (e.g. "Combing Mode" OFF) but without an improvement in travel movements.
In the past I used Cura in combination with an Ultimaker S5 at work to print parts for production usecases. Over the past two years I recognized lots of parts where the travel movements have been chosen very unefficiently at the cost of high print duration.
For comparison I used my standard slicer "PrusaSlicer" and did the test under the same conditions: standard settings, auto-arrangement of the parts.
Overall the travel paths are calculated more efficiently, but there is also some room for improvement.


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My 3D printer checks axes home during print, often wrecking the print
My Tevo Tornado has picked up this habit along the way of checking axes during a print.
(I say picked up because it didn't exhibit any problems when I got it. As far as I can tell the problem presented on their own. The first thing I did to it was flashing the firmware after posting this question as per one of the comments suggestions)
It is mostly fine when it happens on the X or Y-axis, as the only resulting issue is a string on the outside of the print, but it's a problem on the Z-axis as you can imagine. I just had a print wrecked as the nozzle unit got lowered into it and started pushing against it. I used to slice with Cura but have since moved to Slic3r, the issue remains. I don't think it's a G-code problem as it doesn't happen at the same points during prints.
While X and Y-axis checks are relatively common (1 every 15-20 minutes or so) the Z-axis checks have happened only twice on longer prints with devastating results.
I'm assuming this is a software/firmware/settings issue. What am I missing?

Additional information:

Another thing that I've not mentioned but I think it's related: with the same randomness as the axes homing, the extruder from time to time will pull back a good 5 to 8 cm of filament and then pull it back in, stopping momentarily the print and causing blotches and melts.

I've re-flashed the firmware, the issues are still present and I can confirm that the weird movements still occur. So far it exhibits X and Y homing on a shorter print (2hrs). By the way, I say it's homing because that's what I'm assuming it's doing as I can't explain it in any other way, to be honest.

In the file I'm currently printing there are four G28 commands, but they are not in the movement bits of the file. There's one at the start, one after filament END code and two in what I'm assuming are references for defined parameters denoted by ';' after the END filament code as well.

This is what the G28 I was referring to is at the end
M107 ; Filament-specific end gcode
;END gcode for filament
M104 S0 ; turn off temperature
G28 X0 ; home X axis
M84 ; disable motors

It just homes the X axis

The printer also randomly turns itself off and on again during printing causing half-finished prints.

I'm using pretty much the default settings off of Cura and Slic3r, so no fancy editing. The G-code that it spits out is probably as standard as it gets.

There is nothing else connected to the printer (like Octoprint), that could be sending commands. The printer is pretty much how it came out of the factory.

Here's a video of the printer exhibiting the bad behaviour. There is what I thought was the homing of the axes but upon further inspection sometimes it doesn't touch the sensor at the end. The clips where it seemingly almost stops and proceeds to produce a grinding noise are the ones where the extruder is retracting and pulling back in the filament. There are a couple of clips where the printer slows down randomly to a very slow pace. Fortunately no negative Z-axis movements on this print so far. There were many more of these episodes but I didn't catch them on video.

Here are two G-code files a shorter one and a longer one.

Switching the SD card to a different and reliable one has not fixed the problem.

Completely anecdotal piece of info: it seems that the number of errors increases as the printer advances. It seems that at the beginning of a new day, the printer is less error prone, as if it needed a rest.
Just turning it off and on does not yield the same results.
This piece of info might help to narrow it down maybe?

Switching outlets does not fix the problem.

Because of the seemingly increasing nature of the number of errors reported before, I've opened up the housing of the main board to check for any issues relating to cooling. Apart for some dust (now removed), everything seems fine.

I've connected the printer via USB to my laptop and tried to run it through Cura and Pronterface. In both cases any command I send through the software does not get executed. In particular when I run a basic home command or axis movement through Pronterface it spits out the following in an endless loop without actually doing anything:
echo:busy: processing

The drivers are installed on the computer. I can see the printer appear on a COM and it seemingly connects fine. If when connected to PC I send a home command from the printer itself, it won't work but appear as processing in the software as well.

You can't have G28 in filament end G-code. It might be inserted at places during the print. You also can't have it in the job end G-code unless you want to collide with the object after printing finishes, likely destroying it. (In theory you can do auto ejection this way, but it requires a good deal of care for how you do it and it's risky.)

Normally, homing of X and Y is standard practice when the printer has lost steps in case trinamic stepper drivers are used and if correctly set up. I've never heard about Z homing however, that is very strange behavior. Is there any way we could device a strategy to troubleshoot this problem. E.g. is is actually homing, or is the gantry lowering because of the weight pushing it down due to a loss of power (unlikely, just a long shot).

Thanks for the suggestions. I was thinking about filming the printer in action and share with the community the video of the moments it messes up.
I've had this printer for a while but I'm in no way an expert so there might be things I'm missing.

@Greenonline, yes it didn't have any of these problems when I got it. As far as I can tell nothing changed as far as the printer is concerned with it, which is why I'm open to suggestions like Oscars' that it could be a mechanical problem, like skipping steps (?), and the computer has to correct for the inconsistencies by homing.

The SD card is not the culprit I am afraid. It still exhibits the same problems after switching it. I will try with a different outlet to rule out any grounding problems. Will report back with what I find.
One thing I have noticed is, and it could just be completely anecdotal, that the number of errors seem to increase as the print advances.

Ground problems would not be with mains ground, but with the signal lines from the controller (to stepper drivers, etc.) where high frequency noise might cause interference corrupting the data on the SPI bus to the SD card. Do you have somewhere you could try setting up OctoPrint to stream the print over USB instead of using the SD card to see if the problem goes away? Is the problem at the same point each time you print, or different points in the job?

It's completely random. I have a raspberry pi and a couple arduinos. I'll look into it and see if they are compatible with this usecase. Couldn't I just stream it from my laptop as well?
I appreciate you following up with this quirky problem by the way, thank you.

Updated in regards of printer connecting over USB

Does this answer your question? Printer randomly moves to home during printing, then resumes as normal

No. As I've stated in the updates and the comments to this thread the SD card is not at fault.

After watching the video, I see three unwanted behaviors, all consistent with a hypothesis that the printer is reading corrupted data from the gcode file:

Moves to low but nonzero X or Y coordinate then immediately back are not homing, but misreading of the X or Y value for a G1 move command - perhaps flipping a bit so that a leading 1 looks like a 0, or hitting a parse error causing it to be truncated after the first 1 or 2 characters (making it appear to be a value in the range 0-9 or 0-99). The very next command would then move the head back to the correct position since these are absolute coordinates not relative.

Periods of extreme slow speed could be the exact same thing (bit flip or truncation parsing) for the feedrate (F) value in the G1 commands.

Extruder motor clicking could be the exact same thing for extruder position (E) value in the G1 commands.

If this is the case, it's possible that the SD card itself is unreliable (try other cards if you have any), that the contacts in the SD card slot are dirty, that there's electrical noise on the bus (from poor grounding or shielding elsewhere), that the controller board is defective, etc. If the problem occurs in the exact same location each time you print, it's almost surely the card; if it's random it's more likely to be one of the other causes.


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Ender 3 v2 layer skips
I am having some issues with my printer skipping/not extruding random layers of my prints. It happens a few layers in and sometimes doesn't even affect the entire layer. I have tried switching from Cura to PrusaSlicer but the problem persists. My printer is an Ender 3 v2 with dual Z-axis screws, a Micro Swiss all-metal hotend, Micro Swiss direct drive extruder, and a firmware update to reach 275 °C.
I am currently using Polymaker PC-ABS in an enclosure but I have had the same problem with Hatchbox PETG.
I have heard that Z Hop could be the issue when using Cura. I have tried turning it off while using Cura but it did not solve the problem. I have not tried turning it off in PrusaSlicer.
PrusaSlicer settings are as follows:

270 °C nozzle
95 °C bed
0.22 mm layer height.
75 % flow for bridges with a 110° threshold for bridges
0.85 mm retraction @ 30 mm/s
Lift Z of 0.2 mm
3 walls
5 top and bottom layers
20 % gyroid infill
cooling off

This is a known issue with the v4.2.2 mainboard relating to overheating. Continued overheating will eventually result in the extruder controller on the mainboard going bad.
Solution: Mainboard change to version 4.2.7 and raise your unit to create more air flow. You could also add a fan under the printer.


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Creality Ender 3 Pro - Z travel issue with TH3D firmware
TLDR - I’ve just driven myself insane trying to fix what I thought was a physical problem with my Z-axis, but it seems to have been solved by switching from the TH3D firmware to the Creality firmware. I’m hoping someone can help me see where I went wrong here, so I can learn from it. Have I missed something obvious?
My printer is a Creality Ender 3 Pro. I have a BLTouch. I recently upgraded to the silent 4.2.7 board and compiled my own firmware using TH3D Unified 2 using their instructions. This is my configuration.h.
This “worked”, but after that upgrade, I had severe print problems. (See the photos below) These are supposed to be 20x20x20 calibration cubes (the big one is 200%). They are significantly taller than they should be. It may be hard to see in the photo, but this is because the Z spacing on the bottom layers seems to be too high. But, at the same point on each print (even the bigger one), the problem seems to just stop - and layer spacing is correct again for the end of the print.

I tried everything to figure out what this was and I was convinced it was a physical problem with my Z-axis. I read lots of questions on here but nothing quite on topic. I printed on different parts of the bed and got the same result. I re-calibrated my Z steps, but these turned out to be pretty much at the firmware default anyway. I tightened every bolt and eccentric nut I could find that related to the X-axis gantry, but nothing made any difference. Same problem, every time.
Out of desperation, I eventually switched to the official Creality firmware for the Ender 3 Pro 4.2.7 board with BLTouch - and the problem was fixed:

Does anyone have any ideas about what caused this? Have I overlooked something obvious? I’d ideally like to go back to the TH3D firmware but it’s seemingly not an option.
https://pastebin.com/MYs8sYGj

I totally respect the idea behind TH3D software, it is to make flashing firmware easier for a lot of people. But, the problems you experience are one of the many examples that this doesn't work always out of the box, and why I would't recommend using TH3D software, I understand the good intentions from the owner/maintainer (this is not meant as a bash to the developer)! When it doesn't work, the user is left clueless what went wrong. It is far better to use the firmware sources directly from the original repository (no delay in releases) and learn how to configure the firmware using tutorials.

@0scar - You nailed it. This was exactly the problem. I compared the Creality and TH3D firmware settings and TH3D is using M420 S1 Z0.00, but the TH3D firmware seemingly has a default of M420 S0 Z10.00. Sending M420 S1 Z0.00 on TH3D crashes the printer, but M420 Z0 is seemingly enough to fix the issue. I have no idea why this is set to Z10 in the TH3D firmware by default... seems like a bad idea to me. If you want to post this as an answer you can get the points for it!

To correct my comment above for other readers, M420 S1 was crashing my printer as I had no stored compensation matrix at that time (I'd just reset the printer). Like most BLTouch users, I have G29 in my startup G-code which will create a matrix and enable it. So, in this case, simply setting M420 Z0 (followed by M500) fixes my problem entirely, as the fade out seemingly doesn't work well with the BLTouch. I hope that helps someone avoid this!

@0scar Bold of you to assume good intentions in TH3D ;)

Looking at your prints, the problem is possibly related to the fade out height of the BLTouch functionality.
If you look closely at the 20x20x20 mm cube:

half the print is fine (top half of the original correct cube)
the bottom "half" (not really half as it is stretched) is porous (grey, indicating more space allowed than the correct layer height per layer should be).

If you look closely at the 40x40x40 mm cube:

the first "quart" of the 40x40x40 mm is also incorrect (also stretched),
the rest, 3/4 of the top of the print is fine (correct layer height).

Your configuration_backend.h config file doesn't look strange, so the underlying problem could well be more complicated.
A possibility is that there is no reference found to the DEFAULT_LEVELING_FADE_HEIGHT in the linked firmware file. A more in depth answer on enabling/setting the fade height is found here.

M420 S1  ; Enable compensation using current grid/mesh
M420 Z10 ; Gradually reduce compensation until Z=10

It is good to have a fade out height, if zero, the imperfections of the bottom travel all the way to the top of the print; the solution is to use bed geometry (M420 S1) and fade out over 10 mm (M420 Z10).

Just for other people's reference, the "switch" for this (ENABLE_LEVELING_FADE_HEIGHT) and the parameter itself (DEFAULT_LEVELING_FADE_HEIGHT) is found in the Configuration_backend.h of the TH3D firmware (Unified 2 4.2.7 board version)

If you check TH3D's site, as of January 12, 2022, there's an updated Unified 2 firmware(Unified 2.36a) that is meant to correct this problem.
Announcement is here: Unified 2.36a is now live! | Firmware Update

Release Notes:
Bugfixes

Disable ABL fade height by default
Fix EZBoard V2 DIY Config Driver Type Setting

Other Changes

Update URLs in config files to support articles
Improve EZABL mount wording for more user clarity


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BLTouch not probing all points and motors making really loud noises since rebuild of latest Marlin (new hot end installed and BLTouch)
Please listen to this video, which illustrates the issue, with the sound on.
Link to configuration.h and configuration_adv.h

Machine Ender 3 Pro,
New E3Dv6 hotend on a BMG Wind (all has been working and printing PLA, PETG, and TPU fine until I printed a mount and re-added my BLTouch).
SKR Mini E3 1.2 mainboard.

I have rebuilt my firmware after installing a new hotend/direct drive onto my Ender 3 Pro (BMG Wind).
Firstly, the motors have become really noisy if you note the point where the nozzle moves to the middle of the bed in the linked video to do the first probe you can hear the motors making very loud noises, it does the first couple of probes in the middle of the bed which seem fine then moves to the bottom left of the bed to start the leveling procedure. Please also note the motors going from the center of the bed to the left bottom are back to their normal noise.
It then starts the leveling it probes point 1 out of 25 and seems fine, moved to point 2 again probes then the z rises and on the screen, I get a message "endstops z".
I have had all working with precompiled firmware with the stock hotend and BLTouch but as I have added a new hot end and direct drive wanted to start with a fresh marlin build. this is the result.
If I remove the BLTouch and manually level the steppers are still noisy but all work fine and I can print, I'm just trying to understand how the motors have become so noisy in certain motions, (the z-axis is always a bit noisier than normal but the other motors have been fine except when traveling really fast in certain combinations of directions).
Also, for the life of me, I cannot get this thing to probe properly - like I say it was fine with BTT's SKR E3 mini BLTouch precompiled firmware.bin - but I can't get into that to examine the contents, I must have some of the settings wrong.
Can anyone please suggest anything to help? I have googled all night and watched numerous videos but have had no luck at all.
By the way, the new extruder and hot end work fine and after manually leveling the bed I have had some good prints, I just added a mount for the BLTouch so I could have that working as well (I have lost some build space due to the new hotend so the bed is set in Marlin to 210 x 215. this works fine. Also, excuse the wiring I want this working before I tidy all of the wires up, again all works with the wiring as it is until I re-flash the firmware).

Hi John and welcome to SE.3DP. FWIW, this 3D Printing site supports embedded youtube videos, so if you upload the video to youtube then you would be able to embed the video into your post, rather than having people click an external link


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Format SD Card on Mac to update LCD screen on CR-10S Pro
I want to update the LCD screen on my CR-10S Pro.
I've been following the procedure on Teaching Tech and formatting the SD card to FAT32, but the screen either shows the loading screen as normal or doesn't transfer anything.
How can I update the LCD?

On a Mac it is easy enough to format an SD card to FAT32 using diskutils, but this doesn't do it quite properly.
Many resources state that for devices like the LCD on the CR10s Pro, the SD card must also be formatted with an "Allocation Block Size" of 4096, and unfortunately diskutils doesn't do this.
You can force the correct settings using newfs_msdos to format the card in terminal. The process that worked for me is:
diskutil list

Note the location of the sd card, something like /dev/disk1 (be careful to select the correct device)
Then to format:
diskutil unmountDisk force /dev/disk1
sudo newfs_msdos -F 32 -v {name} -b 4096 /dev/disk1

where {name} is the name you want to give the SD card. When you put the card in the slot on the LCD, it should now update correctly.


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Good filament/s for heat resistance in cars
I have designed a cupholder for my center console in my truck with PETG. I was hoping it wouldn't deform and it didn't for a while but we got some high temperatures the past few days (around 32-38 °C or 90-100 °F).
Kind of figured it wouldn't hold up mid-summer but I was wondering if ABS would be my next best choice or if there is something better for this. It does see some sunlight but not a lot.
I do want to start producing some to sell and don't want it deforming in high-temperature areas. Also, I have an Ender 3 Pro so I can't do super crazy filaments.

A previous question ("Can you put PLA parts in your car (in the sun)?") is similar to this one. This answer lists a few materials that can be used instead.

If PETG is deforming in a hot car, you should reconsider where you're buying it from: proper PETG should be good up to at least 70°C (160°F), and more commonly 90°C (195°F).

@Mark not really: it holds shape up to 90 °C, but it loses strength much earlier. 70 °C is about the max for maintaining physical strength. Check https://polymaker.com/Download_File/TDS/PolyLite_PETG_TDS_V5.1.pdf?_t=1563624444

ABS, or preferably ASA which is "a better ABS", is probably your main option. ASA holds up better under UV/sunlight and is easier to print (less warping). Like ABS it should be printed with ventilation, and benefits some from an enclosure but can be done without it or with a primitive one (cardboard box).
A second strong candidate would be real PET (not PETG). It's hard to find as filament nowadays, and might still not have the heat resistance you want fresh off the printer, but it can be annealed with only minor dimensional changes to drastically increase heat resistance to 100 °C or higher. Strictly speaking, you can do this with PLA too, but it's hard to get it not to deform horribly when annealing unless you use 100% infill and pack it in sand or salt or something while annealing. Note that you cannot do this with PETG; it has been specifically and intentionally modified (vs normal PET) not to be able to crystallize (anneal), and to lower the temperaturse at which it softens and melts.
Another great option would be TPU. It's not subject to a glass transition temperature above room temperature (my understanding is that technically its $T_g$ is very very cold, but that may be a misunderstanding) and does not really warp/deform permanently until you reach temperatures near what you could print it at. I've used it as a mold for melting crayons in an oven at 175 ˚F (80 ˚C) with no problem. Depending on your perspective it could be easier or harder than ABS to print. If your extruder is bad at handling flex materials you might have to go really slow, or you might have trouble with jamming on retraction, but unlike ABS it has no heat/warping issues while printing and can be done even on a cold bed, and does not particularly need ventilation (although as always, be careful if you have pet birds around).
Note that while TPU is considered a "flex" material, it can be fairly rigid at high infill with rigid infill patterns like triangles or cubic, or printed 100% solid, especially if you go with harder variants. 95A is typically the highest you see but sometimes you can find 98A.

ABS+ is also a very good option: cheaper than ASA, little to no warping, good temperature resistance. Do UV really affect anything but the most superficial layers? do they penetrate? sometimes I feel it's an overblown issue

@FarO: It doesn't necessarily penetrate, but once the outer layers start to deteriorate they may wear away, exposing the lower ones. UV damage may also make the part turn ugly colors. Personally I don't recommend "plus" materials since you need to also recommend a particular brand, as there's no standard for what they mean. I'd rather recommend things that are reproducible and studyable without relying on a particular secret sauce.

How about nylon? Any experience with it?

@GabrielStaples: I've used Polymaker CoPA nylon, and it's garbage. It prints well but readily deforms under strain (creep). Not just a mm or so, but complete mangling of shape, like PLA under moderate heat. Real pure nylon that's not a copolymer made for easy printing is probably not as awful, but I can't see it being better than or even comparable to easier-to-print alternatives.

If you don't need it to be super precise, nothing beats annealed HTPLA. If you keep it on the bed while annealing you can minimize warping and you'll get a part that can take up to 180 °C. Fusion filaments makes a great HTPLA+ that's reasonably cheap, and you can get it without a spool. Their reusable spool is on Thingiverse. Just don't keep it on the bed if you have a magnetic bed. HTPLA needs over 80 °C which will ruin a magnetic bed.

I regularly print ABS in a fully enclosed X-Max with a bed temp of 100 °C on a magnetic sheet. I've not seen reference for any printer about limiting temps to 80 °C or below.

I can't imagine you wouldn't get part deformation worse than what OP encountered in their car when heating the part to 80°C, unless you print at 100% infill and support it fully while baking.

Personally, I'd get the design just right and then I'd use the "Get an Instant Quote" option on the "Solutions" menu at shapeways.com . It'll be expensive, but you could have it printed in sintered powdered stainless steel or aluminum. You'll want to design as many voids into it as you can, because they charge by the gram. There are cheaper vendors and you may have one locally, especially if you tell them "totally not a rush job" and they can run it with other parts.

While your answer does give an option, the OP is looking to produce the cupholder themself so as to sell online. The option you present adds additional costs that the OP will lose as part of their profits.

I missed the "sell" part. Yep. Nevermind. Injection Molding FTW.

Kinda my bad, I probably shoulda mentioned its an older truck and theres not much for alternatives so this would just be a cheap alternative. and the petg only warped to the wait of itself hanging there on a 100° so it could definitely get pretty hot if the sun was shining in the truck too. Its still hanging there lol, didnt warp it too bad and still functional but definitely noticeable when you look at it


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First layer failing due to delayed and dragged extrusion
I've had a handful of successful prints with my 3D printer, but at some point it just stopped being able to put down a first layer. It looks like the issue is that the extruder doesn't start putting down plastic right away, and when it moves to a new point, drags it along with it.
I've leveled the bed, added a BLTouch, upgraded the extruder feeder after the original cracked, cleaned the bed, cleaned the hot end, replaced the nozzle and tried different filament. Nothing seems to change it.
If I let it continue it inevitably fails completely by the second layer.
Video: https://drive.google.com/file/d/11yFF3Acto4LtDJMBsdVsxr1PvmyMG2qR/view?usp=sharing

Do you start the print with a skirt? What is your first layer thickness? What is your first layer speed? First layer temperature- bed, hotend? Do you use anything on the glass, glue, hairspray? Do you do a nozzle prime move before the start of the print? Do you pull goobers and ooze off the nozzle with tweezers before the print starts?

I think I figured it out! My extruder calibration was way off (set to 93 but measured to 102). I'm thinking that after I replaced the extruder feeder it through things off.

I would not expect that little error in extrusion (10% overextrusion compared to setting) to cause first layer adhesion failure.  Usually that's due to either nozzle too high (= bed too low), or a worn/dirty build surface.  Slow start or no extrusion is probably your Bowden tube backed up from the nozzle -- lots of information around about that, going back to the introduction of the Ender 3 (and all of its clones).


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Do all slicers handle multi object .STL files correctly for multi color printing?
I only have experience with PrusaSlicer, where if I have one .STL file containing multiple volumes, I can click a Split to parts button to then be able to change color of the individual volumes.
Do other slicer softwares handle this similarly or will I face a problem in other softwares?
I'm looking to upload my files for other people to print, and I would prefer to have 1 file per print. Can I upload these .STL files containing multiple volumes or should I rather upload separate .STLs?
Edit: I was mainly looking for typical hobbyist slicers. I was looking to upload the files to a typical online 3d print sharing service for hobbyists.

While there are only a handful common slicers, there are several hundred slicers in existence (some of them proprietary for specific industrial printers!) and technically every maker is its own slicer if they write the G-code manually. please add constraints.

That's a good point. Certainly there are slicers out there that don't even support .STLs at all...

Splitting up the files into separate objects should preferably be done outside a slicer, there are tools for that. Meshmixer, Blender, any CAD program that imports STL files, etc. will do that. You could upload a single file and let others worry about breaking them apart their selves if their slicer of choice doesn't accept a single file for multi colored printings.


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What are some basic good practices I should know when starting to use a ceramic printer?
We have a 3D ceramics printer in our school, but since the access to it is a bit limited, I want to know as much theoretical stuff so I can learn more from each test.
We load the clay inside the printer tube, and it's just like the clay we use for pottery (except softer for the machine) - so we let it dry and fire it like any other piece. It does not use ceramic-loaded plastic filament for burn-out and kiln sintering.

Any tips for using the printer?
Points to consider while building the model?
Any good resource to learn more about it?

I don't remember the specific model, but it's a fairly simple printer, and I'm mostly looking for general tips

It is a commercial paste extruder 3D printer? Not a home made affair? Not to be crass, but is there a manual you could read? It’s a pretty niche machine, and expertise from fdm 3D printing may not cross over, other than the motion system. Not even sure if you can use the same slicing programs.

"I don't remember the specific model"... If you could take a look and add the make and model, that would probably be very useful. Apart from that, this seems to be a bit of an open-ended question.

@Greenonline That's what I was aiming for, I'm looking for mostly general advices and that's why I haven't thought the model is so important

@ChinchillaWafers Thanks, I understand now it's very different. I'll try to update the question a bit more

But that isn't how Stack Exchange works, unfortunately. How would you accept an answer if there isn't a definitive issue to be solved..? IMHO, I think that this question should be closed due to "lack of focus" on any one specific issue that you have with the printer. That said, I hope that you get some good tips posted. Good luck.

I'm not new to Stack Exchange, and in other communities there are for sure questions about guidelines and beginners. I'm not having a problem on a specific, I know ceramics, I know modeling a bit and want to know how to start and what to consider with clay printing. Maybe it's not suitable for this community, and as you're here longer than me and a mod you know this specific community and what fits. You can close/vote closing :) thanks for commenting.

@Greenonline can you close it? I'll come back when I have more specific things or regarding a specific model :)

Some 3D printing basics to look into are layer height and what angle you can build unsupported (and how high since pottery can't take tension like plastic and would likely separate from a base from weight of an overhang).
Beyond that, look into pottery basics.  How will your trapped air escape?  This should affect the slicing algorithms, and how fat a block you can build without cracking.  How will you minimize trapped air between material the printer lays?  Will the shape promote uneven heating (consider the flow of hot air and heat flowing from where it makes contact), and what can you do to avoid cracking from that?
Ponder these before you try it out.  Look at the concepts separately and consider the interactions.  Look at some pictures online and ask why they chose to build that part and in that particular way.

Understanding how material properties and the printer's movement physics interact with part shape is critical to quality in 3d printing.   Even with a good slicer, small changes to part shape that can be insignificant for functionality and looks can drastically change quality and part strength.


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How do I determine the glass transition of filament from its sales listing information?
I need to print some items that will go in my car, which sits in direct sun a good portion of the day and almost certainly exceeds 50 °C inside during the summer months (I've had PLA prints sag quite visibly under their own weight and sliding parts weld together, and PETG prints show slight warpage after a couple weeks in the car).
I have the ability now to print hotter than 250 °C, with Capricorn XS tubing installed in the heat break of my Ender 3.  I'm examining nylon and TPU filaments for their higher temperature tolerance, but I don't see anything on any filament that clearly gives a glass transition temperature.  Is it safe to assume this will be within the recommended bed temperature range, or is there another way to determine this (important, in my use case) value for a given filament?

Capricorn holds more than 250 °C? not according to them: https://www.captubes.com/safety.html Even the XS may hold but is not safe due to outgassing of the PTFE matrix. Ventilate well because some nasty stuff IS being released.

Okay, every time I try A, someone says I need B, and when I switch to B, I get "no, you need A."  Back to the all metal hot end?  And have to swap back to PTFE lined when I want to print PLA again?

TPU does not need temperatures above 250 to print.

The glass transition temperature is not always indicative of strength. Some polymers are solid well above that temperature, see https://omnexus.specialchem.com/polymer-properties/properties/glass-transition-temperature for all the polyethylene, for example.
What you need is the heat deflection temperature, which is very seldomly provided in the datasheets.
Luckily you can very roughly use the Tg for many polymers, but you should know that you are using a value which is only vaguely indicative of what you are looking for.

If there isn't a TDS on the manufacturer's website, you could email them and ask for it. If they won't give it to you, you could ask for the SDS to see if it has any additives. Polymaker has a TDS for every filament they make on their website, so I would recommend their filament for your purposes. I would also suggest you pay more attention to the heat deflection temperature, as it is probably more useful for functional parts.


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Anycubic i3 Mega no fans
I am having a bit of a nightmare trying to work out what is happening to the fans on my Mega Pro.
First off, the part cooling fan stopped working, then not long after the extruder fan also stopped working.
I have opened up the printer and when it is on, the LED for both these fans is always on. Putting a multimeter to them reads ~12 V.
If I send a M106 S255 to the part cooling fan, the voltage drops to ~8.5 V.
Tracking the voltage up to the extruder board, it is consistent until the 2 pin connector for FAN0 or FAN2. Both of these return 0 V.
The temperature sensor and heating element are still working as expected though.
I checked what happens on my Chiron (to compare), the fan voltage is 0 until the M106 S255 is set, then the LED comes on and the voltage goes to ~9 V (which is what I expect to happen).
Has anyone got any idea what might be happening? Is the main board gone? Or is it an issue with just the extruder board?

not sure on that particular printer, but most fans want 5V

There is a speed controller or driver connected to the fans via the main circuit board, check that, because voltage drop usually occurs on the driver IC or circuit, disconnect the fans and touch your multimeter probe on the IC pins and pass the M-code.
If you see a voltage drop as before, then the driver has the issue, if the driver gives 12 V or closer voltage then supply direct 12 V to the fans and test them.
if both of them are working, then some supportive component in your mainboard is at fault.


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How thick should I make my walls for stable 3D printing on an Elegoo Saturn?
If I'm printing buildings that are about 2-3 inches high as scenery on my Elegoo Saturn, how thick should I make the walls? We're talking square boxy-type buildings with basic surface details.
I don't want to make them solid because that would put a lot of material on my FEP at the same time.

For what filament material and what size nozzle aperture?

It's an elegoo saturn. Resin not filament

2-3 inches is... about Z to N Scale?

Unless you can print the buildings upside down, limited details on roof, overhang will be more of an issue than wall thickness.

The Elegoo saturn is a mono resin printer, so everything is printed upside down. Its easier to make the roofs on their own and then glue them on.

Sorry, I don't have experience with resin printers.


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How to remove ABS from PEI Sheet
Recently building a new printer, I went with a Wambam PEX system.  When I began printing ABS I found it did not stick very well and eventually purchased a new build plate and a PEI sheet since PEX isn't suited to ABS.
Not altering some of the setting while trying to get ABS to stick to the PEX I started printing on PEX which is gripping extremely well...too well.  Bed temp may be a few degrees too high, nozzle was giving a little too much squish.  I now have several skirts and now the base layer of a ringing tower embedded in the sheet.  What is the best way to remove these?  I was using acetone on the PEX sheet but I'm told not to use that on PEI.
Just looking for into to clean the PEI sheet, please do not respond on what I should have done, or how to use PEX with glue or whatnot.

Heat up your bed to the print temperature; maybe even as hot as 100 °C.  This will soften the ABS and make it easier to scrape off.  It will distort a print to remove it this way, but is good for cleaning.
Less preferred method: Acetone will dissolve ABS but may be rough on your PEI, even causing it to lose its bond.  It also evaporates very quickly and is highly flammable.  You don't want to breath the fumes.  It is now considered a carcinogen.

acetone may damage the PEI sheet to the point where it no longer bonds the part during printing.

This worked. Heated up the bed to 100 °C but had to use a scraper's edges to pull of the ABS. With a lot of rubbing with edges, it all came off but had to lose the scraper in process since it started melting on the edges.

Heating the bed didn't help much, but Someone suggested using the flush cutters which pryed it up just enough... to get the bigger chunk off.

For me heating the bed helped softening the ABS enough for it to scrape without damaging the PEI.  It's not a perect solution but an improvement.

Update here: even the 105 degrees of the heatbed wasn't enough. Put the PEI sheet in the oven, then the ABS wiped right off with a paper towel. I set it to 180 degrees, but I don't think it even got there.

Hi, are you the OP (tarnis)? Have you created another account to add an update? If you aren't tarnis, then it doesn't seem much sense to prefix your answer with "Update here"? If you are tarnis, would you like your two accounts to be merged? Also if you are tarnis, then it would make more sense to edit your previous answer to update it, rather than posting another answer.

That was someone else


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CR-10 randomly loses connection to computer when printing over USB
I have a Creality CR-10 which is running Marlin because I have a BLTouch installed. All was working fine until it suddenly had an issue where it would lose connection to the computer mid-print when another electronic device nearby was plugged in.
For example: when I plug in my lamp or soldering iron which is 3 meters away, it just stops (doesn't reset, just stops moving) leaving the bed and nozzle hot. The software on the printer is still functional, I can still navigate menus, etc. on the screen but the print stops and can't be resumed from Cura.
I also tried Octopi but it does the exact same thing mid-print and the web interface spits out this error:
device reports readiness to read but returned no data (device disconnected or multiple access on port?)
So it seems I may have some odd interference problem, I guess it could be over the air or through the powerline? I've tried different USB cables, a different power supply for the Pi, but so far, it's still acting up.

I had similar issues when I first started, and I think you are on the right track with interference being a problem.
I have a giant bin of USB cables and started going through them.  Only 2 worked out of about 20, and 1 of those 2 was intermittent with disconnect issues.  The one that ended up working had gold plated leads and was about 8" long.  I assume it probably has some additional shielding of the wires inside as well but I can't say for sure.  It seems that the USB connection is very sensitive to interference.
Also, if it is anything like my Ender 3 V2, you will probably want to use Kapton or electrical tape on the last pin (+5v) of the USB plug, otherwise the display and motherboard kept powered on after turning off the printer's power supply (it was being powered over the USB cable).
Another suggestion would be to isolate the printer power supply from other devices (for example using a UPS made for a PC).

Ok, I narrowed down the problem to USB interference. I powered the printer's 12v line from a battery, that way there isn't going to be any interference through the mains. However, it still does stop during the print when i turn the lamp on. I tried SD printing which worked flawlessly, so the problem must be something to do with USB, i'll try the 5v pin trick later today.

Hey there @Ramsom, Your comment seems like an answer If this answer helped you solve your problem please accept it to mark this question as 'solved', Or feel free to write your own answer if you solved your problem a different way!


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First half of the prints are getting stretched on the Z axis
I have an Ender 3 Pro with a BLTouch 3.1 attached and I have this weird problem. Whatever I print, whether it's a 3rd party STL or my own design, the Z is always getting stretched up to a point and then it fixes itself.
i.e. I printed these calibration cubes at 100% and 150%. While there is a slight wobble on the X axis, X, Y and the top half dimensions are almost perfect.

Not sure if I had this problem prior to BLTouch installation, so I suspect that it might be messing Z jump between the layers somehow but no idea what to look for.
I am using TH3D's Marlin Firmware and I did nothing other than enabling the corresponding flags for BLTouch and ENDER_V44_BOARD when compiling the firmware.

The problem occurs on my custom designs and other models too, so it's definitely not the model
I tried to use Simplify3D, Ultimaker Cura, Prusa Slic3r to slice and then print with Octoprint, Simplify3D or Pronterface, it didn't make a difference.
I calibrated the E steps, so I am not no under or over-extruding.
I also tried to re-calibrate the Z steps so the height would match, which it did but didn't solve the problem. I now have a squished top half and a weird looking print.
The steps/mm values were at default, X80, Y80 and Z400 - as described, reducing the Z to 320 to compensate the height difference didn't help. See the picture below.

I am pretty much stuck at this point, so I'd appreciate any guidance very much!

I just found out about the fade height right after posting this. Guess I am suffering from the same: https://3dprinting.stackexchange.com/questions/16793/creality-ender-3-pro-z-travel-issue-with-th3d-firmware

It seems the DEFAULT_LEVELING_FADE_HEIGHT of the TH3D firmware was causing the issue, which was something I was aware of but didn't think that it would cause this.
I set it to zero and then re-printed the calibration cube. It came out with the dimensions of 20 mm x 20 mm x 20.1 mm, which was incredibly accurate for the setup I have.
Related: Creality Ender 3 Pro - Z travel issue with TH3D firmware

Nice.  Yet another reason I don't feel the need for BLTouch.


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Is it practical to switch back and forth between Bowden and direct drive?
I'm likely to need to print some parts from TPU (Shore 95A or harder) in the near future.  I have everything I need to do a direct drive conversion using the original extruder on a bracket above the hot end -- but for most of my printing (PLA and PETG), this setup isn't required or even optimal, because of the extra moving mass on the X carriage.
It looks as if, once I have the bracket installed the first time, I can move the extruder (including adding/removing a wire extension and switching between full length Bowden tube and short coupler tube) in less than an hour -- in addition to the time I'd need to clear one material from the hot end before loading the other, of course.  Is it practical at all to swap the extruder back and forth like this, on the assumption that I'll want/need to print TPU parts from time to time (I'll want softer material, too, since some of what I want TPU capability for is gaskets).
Obviously, if I needed to print TPU alongside PLA on a regular basis, I might be ahead to have a second printer, but space considerations, more than money, work against that.
Am I missing something on the effort needed to swap the extruder position back and forth (suggesting I should stick with direct drive and pursue firmware and tuning solutions to correct the accompanying problems with faster printing), or should I plan to do this as needed?

Have you tried printing the 95A TPU on your machine? With the right settings, you may be able to without modification. 95A is on the stiffer end, people have done it successfully on their Bowden setups.

@ChinchillaWafers I had thought about that, it's barely more flexible than PETG -- but longer term, I want/need to be able to print much softer material for gaskets and seals (for daylight color print drums, for instance), and I've understood that for that I'll really need direct drive.

With some engineering, you could consider creating a tool dock version where you can easily screw off the Bowden driven hotend and screw on the direct driven hotend. You'll only need to have an extension stepper cable to connect the direct drive stepper and pluggable hotend heater and thermistor connections.
E.g. for the Ender printers, there are Voron Afterburner tool heads that are Bowden driven or direct driven (Clockwork or Galileo mods) available. These could be switched very easily, you do need to figure something out to plug the heater cartridge and thermistor.

I'm doing something similar to my Hypercube Evolution where I am creating a Bowden driven 2.85 mm and a 1.75 mm direct driven tool head.

Putting plugs in a long wire sounds a great deal like a job skill (fourteen years in power tool repair).  Just keeping two hot ends mounted, and switching offsets in firmware or slicer might be another option.  Already got the stepper extension cable (was preparing to mount the stock extruder on the X carriage).

If you use the Voron Afterburner tool head for both Bowden and Direct, there aren't any offsets to consider when you switch heads, only a one time setup offset. You definitely need to set the steps per mm for the extruder if different drive gears are used. Or invest in a board with more stepper drivers, and add a second hotend.

Having two hot ends mounted requires the two to be EXACTLY aligned vertically, or the one which is a bit lower will scratch the plastic printed by the other one.

It depends on the level of automation you are willing to implement.
The Bowden extruder, including the motor, from the Ender 3 which I think you have (but in general, any Bowden extruder) does not need to be moved at all, since it's not on the printing head. You just need to disconnect the Bowden from the hot end and clip it somewhere safe.
The direct drive extruder, if you have a supporting plate which makes it as a single part, can be disconnected with a couple of screws and hanged somewhere nearby.
Depending on the knowledge of electronics you could set up a very cheap relay array (4 relays) all controlled by a single GPIO pin of your motherboard, so that you can switch the motor with a GCODE command. The relay would have the COM going to the stepper driver, the NO connected to the direct drive motor, the NC to the Bowden motor.
Write GCODE macros to change the current, linear advance, steps/mm settings depending on the activation of the relay board (or, even better, depending on the filament).
However, if money is not an issue, I would consider an Orbiter or a Sherpa mini extruder, which is direct drive but with 120 gram weight (including motor, not including hot end) can be used all the time. You are likely not going to push the X acceleration to the very very maximum you can, so you get direct drive at no performance cost.

If money were not an issue, I wouldn't object to the suggestions I've had for remote direct drive extruders -- which add even less mass to the X carriage.

That said, the Sherpa doesn't seem extravagant (never mind it'll likely take 2-3 months to arrive from China).  I'll check for a bracket adapter on Thingiverse.

I bought it from US, printed in CF-ABS. ez3dpstore also offers a 8 teeth motor, while China offers 10 teeth (less torque)

And they're sold out of the motors.  Does the motor include the other gear and the hobs?   They don't show on the page...

The motor is a custom order from LDO, that's why it's in short supply. They get a custom 8 teeth one. The remaining parts should be bought from E3D or clones.

I looked at those extruders in more detail -- with the reduction already present on the Sherpa I don't know that 8 tooth vs. 10 tooth will make a lot of difference.  Sure, 20%, but that only matters if you're coming up short by less than 20%.


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Extruder stops printing before finishing first layer (Ender 3 v2 w/BIQU H2)
Let me preface this with me being quite a newbie to 3D printing, however, I am an engineer and coder, so tinkering with stuff like this is quite the norm for me.  Don't be afraid to be too technical, knowledge is power!
I recently purchased a new Creality Ender 3 V2 based on a friend's recommendation and within a week or two, started getting terrible screeching from the print head fan.  I already knew I wanted to get better PETG (and in the future, TPU) prints so I went ahead and bought a direct drive extruder (BIQU H2) to replace the Bowden setup.
I got everything tuned pretty well (or so I thought), which included tuning the E-steps (945 which is 10x the original value of 93, however normal for this BIQU H2), my home position, changing the retraction setting, setting my K-factor for linear advance, tuning PID, etc.  I flashed these settings into a custom Jyers Marlin firmware.  Everything was working fine, and I was starting to get some really high-quality calibration tests, so I then began tuning my slicer profile.
Then, yesterday, all of a sudden it is no longer printing correctly, even older G-code files before I messed with the slicer settings.  It prints the prime line, retracts, moves, prints the brim, then retracts again, but doesn't start extruding to actually print the model.  I've tried multiple G-code files that were working, and seem to get the same results, nothing prints beyond the first layer retraction or two.  There is no clicking/vibrating or any attempts to move the extruder again after it stops printing.
After some more reading, it seems that maybe I should have adjusted the vRef on extruder driver pots, as the new stepper motor is 0.8a (I believe the original 4042 extruder is 2a).  Is it possible I damaged my stepper driver for the extruder?  From my understanding, it would be moving at 10x the speed of the old stepper attached to the Bowden tube extruder.
Some things I have done:

Completely rebuilt the BIQU H2.  There is no sign of jamming or that there has ever been a jam.  The gears all move smoothly with no areas with additional resistance.  The PTFE heatbreak was clear and freely allowed filament through.  Once re-assembled, I can freely turn the extruder gear when heated and the stepper disabled, and I can extrude/retract using the printer GUI (even after a failed print).  I also checked to make sure the gear was firmly attached to the stepper motor while apart, and it was.  I also added some gear lubricant while I was in there.
Tried a print with the BIQU H2 stepper detached and the wires attached to the old 4042 stepper (and adjusted the steps back to 93).  It seems to stop moving the stepper in about the same place, so I don't believe the issue has to do with the stepper motor which has led me to believe this must be firmware or driver related.
Tried letting the printer sit idle overnight, thinking maybe it was just an overheated driver after running calibration tests almost continuously for 2 days.
Tried printing the same known working G-code with the speed adjusted to 25% and 50%, the same issue occurs around the same position in the print process.

For reference, I have an Ender 3 V2 with a 4.2.2 Motherboard.  I'm not sure what stepper drivers it uses as there seems to be conflicting info online and I don't really want to remove the heatsinks if possible (but I will if I need to get this info and can't obtain it directly from the firmware).  Unfortunately, the drivers are soldered to the motherboard so I guess I will need a new motherboard if I destroyed the extrusion driver.  I do feel I probably should have made some driver adjustments given this stepper motor is 40% the amps, and runs at 10x the speed of the old stepper.
I'm sort of at a loss as to what to try next, any thoughts would be appreciated.  I plan on flashing the stock firmware back later this evening to see if that helps, but I doubt it will.  I have only made some small tweaks mainly related to home offset, build area, PID tune, and K-factor for linear advance (which were previously working fine).
Edit:
I did some further testing yesterday.  Flashing back to stock firmware didn't help at all.  It also seems I may have been mistaken as further testing of the old 4042 stepper was successful if I attached it to the motherboard and ran the G-code which fails on the first layer, however I attached it with a spare cable as to not have to take apart my harness going to the X carriage.  Using the same spare cable with the BIQU H2 unfortunately did not help.  The issue is reproducible without any filament loaded at all as well.  There is an ever so slight play in the motor drive, so I am going to disassemble the extruder again tonight and see if the issue is reproducible with the motor detached from the extruder drivetrain.
Also, just an interesting point, but multiple times after the failure I quickly checked the temp of the heatsinks on the drivers.  Ironically, the only "hot" ones were the X/Y/Z steppers, and the extruder driver was only warm.  Also, when the issue happens, the stepper becomes completely disengaged (I can turn the wheel freely without feeling the resistance of the stepper holding the position).  Not sure if this is indicative of a driver failure, or standard practice for the driver if it encounters significant resistance.
Another interesting point, the motherboard was not grounded.  Although attached indirectly to the frame using screws, the panel the motherboard was attached to was not making contact with the frame.  Some minor sanding resolved this issue.  Once done, I notice the exterior case of my Y motor is grounded, but the X and Z as well as the extruder do not seem to be grounded.  Is it typical for the exterior of the motors to be grounded?  Perhaps there are some other ground faults I need to sort.

Check to make sure you don't have heat creep. See https://3dprinting.stackexchange.com/questions/15629/what-are-ways-to-avoid-heat-creep

@PerryWebb I don't believe the issue is heat creep, as I didn't have any clogs or jams when disassembling.

Are you saying the extruder stopped moving?   With heat creep the extruder keeps moving, but doesn't extrude and the nozzle isn't clogged.

@PerryWebb Yes, exactly.  The extruder just simply disengages from the driver mid print (the motor can free spin as if it was powered off).  I believe I have sorted the issue now, thanks for your suggestion.

Okay, so after yet another frustrating night of troubleshooting.  I believe I have identified the specific problem.  I reduced the G-code file to about 100 lines of code, that 100% reproduced the issue on the BIQU H2 stepper.  With the original 4042 stepper, the problem was intermittent, but did occur from time to time in the same part of the print.
I pulled the motor from the transmission on the BIQU H2 and observed the issue happen without it attached to the extruder and it still failed at the same place (so confirmed it wasn't an issue with the extruder/clogging/etc).  This specific place in the G-code had many quick short movements of the extruder.  Commenting out this block of code allowed it to get past, until it did similar movements on the next layer.  This pointed me to it having to be an issue with either the stepper (which tested fine on my ohm meter, so unlikely), the controller, or the firmware.
Long story short: It was Linear Advance being enabled in the firmware.
I was too hasty to initially disregard the firmware being at fault.  When I retested the original firmware, it was unusable as my offsets have changed with the new print head, so I rebuilt the Jyers Marlin with just a couple small changes for changing the homing as the original Jyers builds works fine.  However I missed that I still had my Linear Advance settings enabled.
After doing some searching regarding Linear Advance and extruder motors, it seems this is a known issue with certain TMC drivers, and my board is one that can potentially have these drivers installed.  It seems the "stealthChop" feature within the drivers causes issues with Linear Advance.  It sounds like it can be disabled via UART but I do not believe there is any interface to the UART of the individual controller chips exposed to my mtherboard.  I believe I will probably need to swap motherboards if I want to be able to use Linear Advance.  I'm still pretty new to 3D printing, so maybe I don't need LA at all, however it did seem to make a positive impact on my prints before I ran into these issues which is why I had it enabled.
Some related references I found:
https://github.com/KevinOConnor/klipper/issues/196#issuecomment-383122655
https://www.reddit.com/r/ender3/comments/bncr8w/silent_board_and_linear_advance/

Check your retraction and run some experiments with it. I just had a very similar problem, when I switched from 0.6 mm retraction to 0.8 mm filament tended to get stuck between rolers and the cooler on layer change.
I don't have and never had linear advance enabled, so it's not the issue.
Unless I've misunderstood and your extruder didn't move at all (mine did move properly)


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What is this printing error and how can it be fixed?
I am not sure what this error is called but would like to learn how to correct it. There is an error at the very top of the print, and then the lower layers at the bottom of the top section.
Printing one of the Low poly tree sculptures from Thingiverse and had no issues with it until I got to the top section of the tree (see photos).
Using:

Maker Select V2
Atomic PLA
Temp 200 °C / 60 °C
20 % Infill
Print speed 50 mm/s

Just a guess (so only a comment), but looks like inadequate cooling.

Inadequate cooling would be my first guess, but possibly also the slicer didn't put enough support under those top layers.  The bottom layers might be unsupported overhang as well.

In regards to the cooling I am going to print and install that shroud fan mod for the V2 and give that a try. Are there any settings in Cura I could look at to increase the support of those top layers? I am not very aware of infill/support configs...

This looks a lot like inadequate cooling as others suggested. A important aspect to consider is how long the printer spends on a single layer in the trubble areas and how big that area is. The faster a given layer the less time it has to cool. The smaller that area more time the hot nozzle spends in that vicinity heating the surrounding already printed plastic.
Some simple options to fix the issue:

If it's adjustable make sure part cooling is enabled by the slicer and that it's at the maximum fan speed at the issue areas.
Print additional parts to lengthen the print time at the troublesome Z heights.
Slow the print speed. However this can backfire if its too slow as the hot nozzle will remain in the same area for even longer and some extruders can jam if the flow of cool plastic is too low, causing heat to climb past the heat break.
Add a external fan to the increase flow of fresh cool air to the area.
Reduce nozzle temperature. Can be combined with slower speed as a slower flow rate of plastic can reduce the minimum required print temperature.
Add perimeter loops to the print to increase print time. This might not be as effective for a small area as it only adds more heat in a localized area.

A more permanent solution would be to improve the cooling by modifying the ducting or fans. However do be weary of untested fancy fan shrouds reported to improve the air flow as it is easy to make it worse then it was.


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Extrusion issues on medium speeds (while accelerating?)
I've recently changed my Ender3's hotend to E3D v6 clone with Titan direct extruder, so I can print faster than on stock. But when I increased the speed up to 70 mm/s for walls and 80 mm/s for infill (PETG, nozzle temperature of 225 °C, bed temperature of 80 °C, 0.2 mm layer height, 0.4 mm layer width), I've faced this kind of issue:

Here's how it looks in Cura:

The printer's head goes from left to right, counter-clockwise and I get issues on both exits from curved shape.

First of all, I thought, it is connected somehow with retraction, but according to Cura, both problem places are in the middle of the current layer. Later I thought it could be related to Linear Advance and disabled it on the next test print, but it did nothing:( Slowing the printer down to 60-65 % in mid print solved the issue, but it's not what I changed the hotend for:)
Maybe someone has any ideas, what's wrong with it?

Petg doesn't like extruding fast.

In my experience, 225 °C is the lower range for PETG, that combined with a higher than normal printing speed of 70 mm/s might be your issue. The lower your print temps the lower the maximum nozzle flow rate. I would recommend increasing the nozzle temperature.
For a point of reference, on my printer with an E3D v6 clone and a generic extruder I print PETG at 235 °C and 60 mm/s and 24 mm/s outer perimeter speed, with a 0.2 mm layer thickness. Though admittedly not optimized for speed.

hmmm, maybe it's really the temperature question Thanks for the tip! I'll try it and come back with results:)

In other words, your print exhibits issues when the hotend is accelerating, like if not enough filament were pushed in.
It is advised to calibrate for linear advance after replacing the extruder.
Check https://marlinfw.org/docs/features/lin_advance.html and

and check https://marlinfw.org/tools/lin_advance/k-factor.html

Yes, I have a calibrated LA and on the pictures it is enabled. "Later I thought it could be related to Linear Advance and disabled it on the next test print, but it did nothing:("

buuut, of cource, maybe my current settings isn't enough. So I need to calibrate it more

PETG can have difficulty printing at higher speeds.
See Why does PETG require slower speed?
Also, if the speed is too slow, it tends to have heat creep.
See What are ways to avoid heat creep?
Higher nozzle temperatures should allow faster print speeds, but will also increase the chance of heat creep and increase the slowest required speed to prevent heat creep.

But I don't have such issue printing infill on 70 mm/s - https://imgur.com/a/8ixtmnP . All the infill lines are clean and even.

And also, the most recent and approved answer you gave link to says:
"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."

If it were a problem of speed, why is the issue appearing when exiting corners, instead of in the middle of long segments, which are printed faster?


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How to send G-Code directly from a Raspberry Pi to my printer without using any extra program/software
I want to plug in my drivers from the printer into my Raspberry Pi. I want to control the printer's axes by sending G-code directly from the Raspberry Pi command line (if possible) to the drivers.
Is that possible and if yes does anyone know how? As I stated above without using any 3rd party program/software.

depends on what the printer accepts.  if firmware will accept g code over serial, you just need the correct port settings...

Okay how can i see what my printer/firmware accepts?

A very dumb, simple way to send GCODE to your printer from the terminal can be achieved with:
echo "gcode here" > /dev/ttyS0
/dev/ttyS0 can vary, It may be /dev/ttyACM0, /dev/ttyUSB0, or any similar with a different number.
You can figure out which path is correct for your printer with the command ls /dev/tty* and comparing the results with your printer plugged in and unplugged, Whichever device pops up new should be your printer.
As well, Some printers may appear in /dev/serial/by-id/ instead of /dev/tty*, so if you can't find your printer normally, try ls /dev/serial/by-id/ instead.
If this doesn't seem to work, you may need to change the serial settings using the command sudo stty -f /dev/ttyS0 115200, replacing /dev/ttyS0 and 115200 to the device path and printer baud rate respectively.
If you are looking for a more bi-directional solution, you can use the command screen, which is usually installed by default. You can use it like this:
screen /dev/ttyS0 115200 and exit by Control+A, then pressing D
Another solution would be the pronsole utility from Printrun/Pronterface, which can be installed using sudo apt install printrun and invoked with pronsole.py and you can then connect to your printer with the syntax
connect /dev/ttyS0 115200 or simply connect, as pronsole has the ability to autoconnect to your printer. Exit with the exit command.

You can send the data to the serial port using echo, but you'll have to use cat to get the response.

Your answer was flagged by the system as being a little short. Could you [edit] and expand your answer and provide examples of the commands in use (maybe with dummy data)?

Sending G-code to a printer via a serial interface is a bidirectional operation that requires waiting for acknowledgment from the printer before sending further commands. In theory, this shouldn't be needed and hardware flow control (or even XON/XOFF flow control if the hardware is not available) should be used, but that's not the way things were done. Thus, sending G-code with "dumb" commands like "cat" does not work.
If you want to send individual commands manually, you can use a program like Minicom (or screen's built-in serial terminal support) and process the acknowledgments yourself. But if you want to really stream print jobs, you need at least a minimal program for it. This can be written in a few lines of Python or Perl if you like. I know there are examples of such but I don't have the links handy and haven't tried any of them to be able to recommend one, anyway.


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Why is my outer wall layer printing with gaps and flaking off on this specific shape?
Printer: Ender 3 Pro - Direct drive, BLTouch, stock magnetic print bed surface
Material: PLA - multiple brands
Slicer Settings:

Layer Height .2 mm
Initial Layer Height .1 mm
Line Width .4 mm (with .4 mm nozzle) and also tried .39 mm
Wall thickness 1.2 mm (3 lines)
Hot End 210 °C
Bed 60 °C
Print Speed tried between 40 and 100 mm/s
Retraction Distance 6 mm  speed 25 mm/s
Print Cooling- Initial 3 layers 0 %, then 100 %, also tried 50 %

I designed this in Tinkercad and sliced it with Cura for the Ender 3 Pro.  When I print this specific shape at this size the outer wall does not print properly, there are large gaps and it does not bond to the rest of the model so it just flakes off as soon as you handle it.  I can print other shapes fine- see the color swap example that was printed with the same settings successfully before AND after this series of failed prints of the same design.  Sometimes I get a clean first 15 layers then it goes to crap, and cleans up for the last 10% or so.  If I scale it down to 50 % it prints fine, but it will NOT print properly at full scale.
The infill and inner walls seem fine, but the walls are definitely not air-tight with what is left.
Looking for more things to try and troubleshoot, so please send me your ideas!
Troubleshooting steps so far:

Re-downloaded the files and resliced with all new settings
Adjusted the print speed, wall line width and fan speeds
Tried multiple PLA types and brands

You say it prints fine at 50% scale -- have you closely examined the preview of the gcode in your slicer?  This looks like you're getting travels where you want print...

Honestly, I have no idea how to inspect my gcode or what I am looking for, but I suppose that will be added to the list of top things to learn!

I was referring to the preview function in your slicer -- Cura, at least, lets you view the result of the slice operation, scolling up and down layers and along the extruder path within a layer.  Only available after "Slice" is completed, of course, because it's interpreting its own gcode.

Do you still have this issue after reducing retraction distance?

I don't think reducing the retraction distance did a whole lot but it was still the right move. I purged the nozzle at a higher temp (and ultimately replaced it) and am still getting bad layers on PLA with any design I print.  I was down to one roll that has been open for several months and I live in the Pacific Northwest, so now I am suspecting I may have some moisture affecting the prints.  I ordered a new roll and am running a test print now that failed repeatedly with the old stuff, so far so good.  I increased my hot end temp to 220 and changed to a glass bed to get the flattest surface.

Assuming you do have a direct drive system as described.
Is this correct?

Retraction Distance 6 mm speed 25 mm/s

A retraction distance of 6 mm for direct a drive is huge and could easily be pulling the filament out so far it might become problematic. Most of my direct drive printers are 0.4 to 1 mm. In addition the 25 mm/s appears to me to be on the low side, though it would not surprise me if it's highly extruder specific. Most of my retraction speeds are 60 to 90 mm/s.
Faster retraction speeds can actually be more effective at stringing reduction then adding distance as. Faster travel will also reduce stringing as the nozzle has less time to ooze.
Are you incorrectly a using a Bowden profile?

Enders are normally bowden machines and OP didn't mention converting it.

@R..GitHubSTOPHELPINGICE Added at note of that discrepancy, thanks.

I was indeed still using my former bowden tube settings and never looked into what the direct drive retraction settings should be, so thank you for pointing this out and giving me a place to start.  Unfortunately the more I try the worse it is getting for all PLA prints now, but PETG is still printing fine with the same setup.  I am noticing a clunking sound occasionally during the print, so I probed the bed again but still getting the same results.  The nozzle is clean and only been used on a dozen prints or so, is it ok to use the same nozzle for PLA and PETG?  Could that be a cause?

@EricArcher I've switched back and forth between PETG and PLA a couple times; you just need to be sure you purge while within PETG temperature range (usually a bit hotter than PLA) to clear the nozzle and heat break when you switch back to PLA.  If you didn't purge the PETG within its print range, it may not be soft enough for PLA to push out at PLA temperature.

@ZeissIkon As soon as I read this it was a facepalm moment, of course I need to purge at the hotter temp, but I failed to do so!  How much material do you feed through when you purge?  I am using OctoPi as well so I just set it to extrude 25mm and ran it three times.  I am running a test print now and will report back.  I am also noticing that my rollers are starting so show some ware and my gantry has a little play to it. I have ran this thing almost every day for 8 months, I think it is time for some serious maintenance.

@EricArcher I generally have a color change, so I feed until the extrusion is cleanly the new color.  Usually takes, IIRC, 10+ mm of extruder movement, might be as much as 20.  I don't watch that, and often just hand push the filament with the extruder disengaged.

Promoted from comment: if you had switched from a higher temperature filament to lower temperature, you need to purge the hot end at the higher printing temperature to ensure the old filament is sufficiently fluid for the new to push out.
If you don't do this, pulling the old filament may leave a "core" passage that lets the new filament get to the nozzle, more or less, but the lining of old filament in the nozzle will both limit thermal transfer (plastics are generally poor conductors) and restrict flow even when the new filament is well melted.
This will result in a preheated nozzle printing acceptably until the filament carries away too much heat, then grossly underextruding when the flow rate rises (larger layers, print speed increasing after initial layer slowdown), and potentially partially recovering when the layers get smaller or (due to slicer settings) the print speed slows near the top of a tall part.
Solution: when switching filament, ensure that your purge cycle (whether manual or automatic) is done at the higher temperature for the two filaments involved -- if switching from PETG to PLA, for instance, you'll likely need to purge at 220 °C or higher, even though you'd print your PLA at 180-220 °C,

You appear to have severe underextrusion. It may be that you are trying to melt plastic faster than your printer can physically accomplish which would explain why it starts good and then the nozzle gets cold and then as the layers get small it comes good.
That doesn't explain why reducing the print speed doesn't help. Double check that it is actually slower.
I have had similar issues with cura that were fixed by altering the configuration, like tilting the model slightly or changing print orientation.

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.


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Ender 3 V2 printing weak and messing up on the top 1/3 of the print
I’ve had this Ender 3 V2 for about 6 months, and it has been printing great, but every now and then I will get a brittle messed up top on my prints. I can simply crush these tops by just touching them, they are super weak. The odd thing is it does not happen on every print.

What kind of material are you using? What are your settings? Do you have photos of the printed model? The more information we have, the better we can diagnose the problem and offer a solution.

Most likely this is a symptom of an under extrusion issue.
Could be heat-creep. Could be caused by a overly aggressive auto cooling setting where the minimum layer time is set so low that heat has time to climb up the filament and heat break causing a jam. Or other related reason such as the print speed is very low at a specific point in the print. This type jam can self recover with a temperature cycle of the nozzle so might not be noticed as the next print could be started without any intervention to clear it. The weak area of plastic could simplify be what oozed out of the nozzle after the jam.
Given the limited information I cant say much as to the cause.


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Thin bead not adhering to itself or bed very well, what am I doing wrong
I'm just learning how to use a 3D printer, I have an Anycubic Mega Zero 2.0.
When I start printing the PLA filament doesn't want to adhere very well. I have leveled it out and all of my corners on my test print adhere well. However, when I go to print anything besides the test print I get basically a small bead - it doesn't smooth flat. If I try and adjust from there it starts pushing all the material around.
This lack of adhesion and bead continue throughout the print making it flimsy. It's weird because it looks nice but it's not strong.

As 0scar requests in his comment, please [edit] your question and add print and bed temperatures, filament diameter in slicer and the actual used diameter. Thanks.

If you look at the multiple lines of the skirt, you see that none of the printed lines are touching the other laid down lines. This is an indication for under extrusion or a too large of a gap between the nozzle and the bed (or both). Considering you are talking about a bead/drop/blob of hot filament not adhering to the bed, this might be a good indication for a too large of a distance, if the gap is too large, the filament will not adhere to the bed and forms a blob. You could consider decreasing the gap by leveling with a thinner piece of paper or feeler gauge first. An alternative that might be quick to test is to re-define the bed height prior to printing using a plug-in in Ultimaker Cura or manually inserted in your G-code file. E.g. in you start code, add a move to a certain height and define that to a different height:
G1 Z0.2 ; move printer head to 0.2 mm height
G92 Z0.24 ; re-define 0.2 to 0.24 mm, if the first layer prints at e.g. 0.2 mm,
          ; the printer will move down 0.04 mm

The images aren't very sharp, but, from one of the top layers it looks like you are indeed suffering from under extrusion. First, check if the filament can unwind freely without too much force from the spool. Second, under extrusion should be fixed by adjusting the steps per millimeter value. Beware, a new printer should have the correct value already inserted in the firmware, you should definitely check the filament path for obstructions first.
A glass bed should be pretty flat, but it has been reported that there are glass manufacturers that produce low quality glass beds with dents. If so, you could shim the middle of the heated bed. An alternative is to flash new firmware and mesh the glass bed and the printer will automatically adjust for the height; this is not recommended for beginners.
You could also increase the temperature of the bed, PLA can be printed on a cold prepared bed, but works very well on beds at 50-60 °C. You could consider using an adhesive on the glass as well, certain hairsprays, certain glue sticks, and special adhesive print sprays like 3DLAC work very well.
Last but not least, incorrect filament diameter can cause under extrusion, older versions of Cura are notorious for resetting the filament diameter to 2.85 mm when you need e.g. 1.75 mm.

Initial z heigth too high can cause both poor adhesion and 1st layer lines not sticking together because the extrusion width is off from not being pressed down.

Indeed, hence the answer starts with checking that first.

This looks exactly like you are extruding less plastic then you should be. Gaps can be seen on the top "solid" infill layer and even more telling is the gaps from one perimeter loop to the other. Suffering from weak prints is another indication of this. (or low extruder temps)
You may find solving the under extrusion issue goes a long way to assist with the bed adhesion issues you are having. I would recommend you first solve that and then see if the bed adhesion issue is still present. At the very least it should make is easier to dial in the bed adhesion.
If any slicer changes or tuning was done a quick and easy sanity check would be to download and run a print with known good profiles for your model of printer. It's easy to chase and tune for one issue and unknowingly create another that shows up at a later time in a different print, especially if you are new to 3d printing. (ask me how I know)

If the print bed is contaminated with oil or fat, print bed adhesion may be too low. Cleaning with alcohol might help.


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My printer does not execute any command over USB
I have a Tevo Tornado, it seemingly connects fine, it is recognised by the software and it turns on.
Any command I send over USB is not executed, as if it's not registering them.
I tried on Cura and Pronterface and the printer is unresponsive.
In particular in Pronterface it displays:
echo:busy: processing

but nothing is executed.

This is part of a broader set of problems I am trying to diagnose on the printer; most of them are explained in this question.
I am trying to section off the individual problems and fix, bit by bit, the whole printer.

What command(s) did you send that got that response?  Valid gcode?

Anything from homing to a G-Code file to print.

Have you tried a different USB cable?

Yes. FYI this is part of a broader set of problems I'm trying to diagnose on the printer.
If you are curious you can find most of them explained in this question:
https://3dprinting.stackexchange.com/questions/16790/my-3d-printer-checks-axes-home-during-print-often-wrecking-the-print
I'm trying to section off the individual problems and fix, bit by bit, the whole printer.


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Adjusting layer exposure time for different layer thicknesses
I purchased a bottle of Siraya-Tech Simple Clear and Siraya-Tech has good documents on their resins with printing guidelines like for the simple clear (see their Simple User Guide).
This gives good curing times for different types of resin printers, but they are all listed for 50 microns layer height. If I wanted to print at different layer heights, I am assuming the curing times would need to be adjusted, but I don't have a good feel for how much they would need to change.
My first print was the Make: Rook Resin Printer Torture Piece, and given how short it was, I thought I would try pushing things to the limit and printed it at a 10-micron layer height, but I used the curing times in the guide above for the Elegoo Mars (figured it was the most similar to my actual printer the Halot-One), and as soon as I started the print I realized that I probably should have changed the layer exposure times. I was shocked how well it turned out for using the times for a 50-micron print, but there were parts of the print that looked like there may have been a little bit of light bleed because of the longer exposures for the thickness, and the print definitely took a long time for how small of a print it was.
So, my question is, if I have good times for a 50-micron print, are there rules of thumb out there, or have experiments been done, for how much to adjust the exposure times if you want to do a 10-micron print, or say a 100-micron print? I would imagine it's not as simple as reducing it by 5x for a 10-micron print or doubling it for a 100-micron print.
Key parameters that would need to be adjusted:

Exposure for initial layers
Number of initial layers
Layer exposure time

Based on my experience, cure-time and thickness increase or decrease is not linear and it is mostly curve. For example resin rated for 50 micron 5 s cure time. You should expect:

25  micron - 3.2 s
50  micron - 5 s
100 micron - 12 s

If a resin manufacturer do not provide specific cure time for thickness you want, you should always print calibration objects.
You can cure specific range of thickness depend on resins chemical properties (eg. uv blocker and photoinitiators), usually for non-specialized resins, you may print 1/2 or 2x of the suggested thickness. So you cannot print 10 micron for resins which designed for 50 micron thickness. For some specialized resins you can only print with the rated thickness and nothing else.