text:
CR Touch install help
I bought my son an Ender 3 Pro and a CR touch. I am trying to get this setup to print for him despite having zero experience with 3D printing and at a loss with the installation.
Here are the details:

I have the 4.2.2 motherboard.
I have reviewed my CR Touch install and believe it to be correct.
I did the formatting of my SD card.
I have downloaded and installed this firmware: Ender-3pro_HW4.2.2_SW2.0.8.27_CRTOUCH.bin.
I am having the "homing failed message".
When I try to move the Z-axis, nothing happens (the printer sits idle).
I have read about adding the G-code however have no idea where to do this.

When I power the unit on, something doesn't seem right. I have read the provided install directions, searched Youtube videos, and read through this site to no avail. I just need somebody with some experience here to help walk me through getting this setup.
I did not use the printer prior to the CR Touch install.

Have you tried the CR Touch Install Guide – Complete Walkthrough! YouTube video?

@agarza Although the video explain the hardware and software adjustments to get a sensor working it also shows us why you shouldn't buy an Ender 3... Look at the XZ gantry when the sensor hits the surface OMG, left is going down and right not... Not a very good instructional video to promote touch sensors on the Ender 3.

Can you make the basic Ender 3 work without installing the touch? If not, the problem is likely on that side.

There are so many pre-compiled versions of firmware available of which some don't work well and others are labeled incorrectly or not enough.
For this reason many people compile their own files; you are in control of the options of your choice. But, building your own firmware requires some skills, so it is imaginable that some like to use pre-compiled files.
Another compiled file you could try is this one:

In this file- Firmwares of CR Touch for Ender-3 Pro Series with 32-bit motherboard. Before update any firmwares, please refer to "CR Touch Firmware Version for 32-bit Motherboard" for more details on how to select firmwares.

According to the latter link, you require firmware file "Ender-3pro_HW4.2.2_SW2.0.8.27_CRTOUCH", so you should have the correct version! But, there appears to be a consensus to not use Creality pre-compiled firmware! It appears that the firmware doesn't work (well).


text:
'Ask' printer for printing status
I'm using Artillery Hornet printer running Marlin firmware.
Is there a way to ask/query printer status via its USB/Serial interface? Without OctoPrint, etc.
Example (something like this):
Arduino: Hey are you done printing?

Printer: Not yet

This idea is inspired by vehicle OBD, where you can query the engine RPM by sending a PID through CanBus interface. So, I wondered if we could do something similar with a 3D printer.

Without OctoPrint implies SD printing, look into M27. I've never used it so I don't post an answer.

source: Stack Exchange

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

sort: votes


text:
Ender 3 v2 temp fluctuations every 10 minutes or so
I have an Ender 3 v2 that will fluctuate the hotend temperature every 10 minutes or so and eventually causing thermal runaway. I have tried the PID auto-tune a few times and it seems to solve it for a couple of days. Any idea what’s going on?

Today I ran the PID auto-tune again a few times trying to figure out the issue. Now when I heat the hotend to 220 °C it holds perfectly for about 15 minutes then drops and goes into thermal runaway shutdown. I heated the hotend while the printer was not printing to eliminate a bad electrical connection as the issue. Is this maybe a thermistor issue?

Have you solver this issue yet? Have you checked for loose hotend thermistor?

It turns out this was the beginning of the hot end thermistor failing. I took the opportunity to upgrade to an all metal hot end. That was the start of a nightmare that lead to the failure of my mainboard. But it is working now and no temp issues after several months and many prints.

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


text:
Ender 3 Pro extruder keeps clogging
I'm fairly new to 3D printing and looking for help. I have an Ender 3 Pro and it's been working great up until about a week ago. When I preheat the extruder, the nozzle gets hot as it should, but it keeps jamming mid-print. About an hour in, the filament stops feeding. The gears are still trying to push it through, but it won't go.
After a bunch of troubleshooting, I eventually unscrewed the fitting where the tubing and filament enter, and even with the nozzle still fully heated up to 205-215 °C, there's a cooled, solid blob of filament sitting in what I believe is the heat sink (just above where it goes into the nozzle).
Does anyone know why this would happen? I'm using new filament, but I've tried 3 different spools all with the same result.

Did you clean the nozzle?

In order to solve this we may require some additional information. Please post photo's and printer settings, we have a nice template available with the basic information. This sounds like heat creep, but we know for sure if we see photo's of the print and the print settings.

The nozzle has been both cleaned and replaced, twice. I'm using similar settings I've used before for the same prints. The only difference is it's new filament, but I've tried cranking the nozzle temp all the way up to 215 and it will still get a clog.


text:
Broken stepper motor?
After encountering extreme under extrusion on my Anycubic i3 Mega, I first cleaned the nozzle and ended up replacing the entire hotend + nozzle. Since that did not help and I couldn't see any issues with it, I went on to check my E-steps. It seems that this is the root cause of the issue.
I removed the Bowden tube to have no resistance and used G1 E100 F100 to feed 100 mm of filament through the extruder. The extruder only extruded ca. 23 mm though, so I had to adjust the E-Steps value from 92 to 398 which already seemed way off, seemingly "fixed" the issue though. When I repeated the test "under load" with the Bowden tube connected and the hotend heated to 220 °C (using PLA I normally print at 200 °C), the extruder once again only extruded a fraction of the supposed 100 mm (I don't remember the exact measurement, though approximately 30 mm). The gears seem to be fine, and the filament that is pushed against the small gear doesn't seem to slip either.
Unfortunately, that's where my experience ends, can someone tell me how to proceed to narrow down the issue? I suppose it could be the motor itself, a faulty stepper motor driver, loose cables, or the mainboard.
Edit to @Citadel:
When I bought the printer it had a spare hot end that came with it. I simply replaced the old one with this one. I did not do any further hardware customization.
Edit2:
Sorry for the late update, I wasn't able to check the printer before due to work. I swapped the stepper driver with one of the others on board and checked the e-steps again. Aaaand I just then I noticed I must have forgotten to save the to eeprom when I updated the e-steps last time... So of course I tried with the swapped stepper driver and original e-steps (92), but this didn't fix the issue. So the issue is not the driver. After that I changed the e-steps to 398 again and saved this time. Last time I accidentally started a print that that caused the eeprom reset before I saved the settings and tried the e-steps under load. This time it worked, even under load. I still believe this must mean that the motor is missing some steps but for now it seems to print fine. If I get issues again I'll next try to swap the motor. Thanks for your answers!
TL;DR: forgot to save the new e-steps due to starting a calibration print that reset the value before saving. New value actually works but probably indicates that something might be wrong with the motor as the stepper driver is fine.

Easy first step would be to swap the extruder motor with another and see if the problem follows the motor.

Depending on the machine architecture, it might be easier to swap a motor driver board. Some are integrated, some are modular. I'm not familiar with that printer.

After you first had the under extrusion, what was the hardware failure that required replacing the hotend assembly? What new hotend assembly did you buy?
Did you remove the Bowden tube because you began using a direct drive hotend?

okolaris, could you [edit] your question and add the info that @Citadel has requested? Thanks in advance.

Make sure that you do not have volumetric extrusion (E in mm3) enabled in the printer's menu system.

Thanks, for the reply! Are you talking about the M200 command in marlin?

@okolaris Not exactly. A common error is to accidentally enable volumetric extrusion in the printer's firmware, but to have the slicer set for linear extrusion. This will cause massive under-extrusion. Another common error that will cause massive under-extrusion is to set the filament diameter in the slicer to 2.85mm (Cura's default value), when your printer uses 1.75mm filament, but this has nothing to do with volumetric extrusion.

That sounds plausible. Though I am not aware that the Anycubic i3 Mega has such kind of setting in the menu. I couldn't find any info on this either apart from the mentioned Gcode?

Using a Bowden drive system, you should never need to resort to testing the drive system without the Bowden tube. The tube acts as a neutral surface that retains the force of the plastic through the hotend. Try replacing the nozzle and fully cleaning the hotend following a YouTube video. If you don't have a hotend motor with a set gear, please test the uniform turning of the gears to see if the gears are slipping on the motor.
Make sure the Bowden tube is not clamped flat in any area. 220 °C is fantastic for PLA testing.
Please check out The almighty word of the 3d printing gods regarding underextruding and use it to become a better print mechanic and to be forgiven of your 3D printing sins. This reference holds dominion over all printers in existence, wield it responsibly.

Hi Citadel and welcome to SE.3DP..! :-) Try not to put follow-up or clarification questions in your answer (as this might lead to the OP try to use the answer section as a follow up post with more detail). Any requests for clarification and extra info should go it the comments under the question, so that the OP can edit their question and add the info there. However, as you need 50 rep points (you are nearly there!) to leave comments I have stripped the questions from your answer and put them as comments for you. :-)

However, if you wish to edit the questions (that were at the top of your answer) into statements of fact, then please feel free to do so. Also, whilst linking to external sites is fine (for reference), the main points from the link should be included in your answer itself. This is because should the link die (see link-rot) then your answer won't be as useful.

Hi, thanks for your reply. As stated in the post, Bowden tube, hotend and nozzle are new (got them included as spare parts when I bought the printer).


text:
Ender 3 - mobo 4.2.7 - driver adjustment
I upgraded my Ender 3 with a new Mobo, the 4.2.7 version.
My current setup is:
Printer Specifications:

Ender 3
Upgraded Motherboard 4.2.7 (Silent Stepper Drivers)
Marlin FW Upgrade to Version 2.1.x
New metal extruder handle
Replacement bed springs
New complete hot end
Everything else is in stock

Prior to the mobo upgrade, everything was working fine. Now I'm having problems with the extruder.
I did use at first the Ender3 32bit 4.2.7 firmware, but it did happens too.
The e-steps for the filament length have been adjusted. Once I start spinning the extruder, the extruder stepper starts grinding and jumping/rewinding the extruder wheel with the filament to the back; sometimes even 8-10 mm. Also, if I manually hold the filament back, it springs back. It seems that there is no power/power coming from the stepper motor.
So I would like to check how much power the driver needs and gets.
How or where can I find the required voltage for the drivers?
How to adjust the drivers?
Any tips or references are welcome.

There are different versions of the 4.2.7 main board. This is an excellent video made by YouMakeTech:

To prevent the answer to become unusable due to link rot, a concise summary is shown below.
The correct drivers can be "read" from the written letter on the card reader:

Depending on the driver, you need to find out what the maximum Vref for your stepper is (this depends on the maximum current rating of your stepper), e.g. for 2208, 2209 and 2225 drivers the Vref is calculated by the same equation:

The Imax (maximum curretn) is depending on the used stepper:

Use the nominal values to prevent the steppers to become too hot.
The Vref can be adjusted by the screw potentiometers next to the drivers, use a voltmeter while adjusting:

So great explanation. I will check your post. Thank you

I would try to reinstall the old board and see if the extruder still skips.
If the extruder is not having an issue with the old board installed, you'll need to visit Creality's Updates page and install the Marlin 2.0 firmware designed for the 4.2.7 board. Please use a how-to video on YouTube for installing your new board, you will need to calibrate E-Steps, calibrate PID Temperatures, etc. as outlined in the video.
If the extruder continues its behavior, the extruder is under-extruding. Please check out The Holy Bible of 3D Printing troubleshooting: Underextruding printer to get to the bottom of it before you upgrade to your new silent board. Then I can pretty much guarantee you have either a clogged nozzle or a hotend that's too cold during printing to melt the plastic at a fast enough rate.
The third thing is you need to upgrade the stock Ender 3 extruder because the stock black extruder bracket is absolute garbage, and it alone would cause a skipping and flaking extruder. Get the sweet stainless grey one for 15 USD on amazon. Blame Creality for that oversight.
Please respond back if this didn't help.

Thank you for your reply. All the items that you describe is already investigated or was replaced at the moment at the change. -  Even when I left it run through freely, with only a tube it happens. I can push the filament back during having the extruder stepper run with 'motion' and with a 200mm run setting. The metal pressure handle is tight; for testing I did even put a washer behind the spring to get even more pressure to no avail. What I can try tonight is to exchange the Z and E cable ( at the stepper side ) and run 'motion'->'Z' to see if there is a difference.

BTW, Under extrusion will never let the wheel and filament jumping back. The part in the article where it reads 'The motor is Clicking' looks more like the symptoms. Also I would like to check the voltages to have them right and sure.

@iPadawan Ok if you have isolated the problem to the bowden tube itself, I'm guessing you have a bowden grip/clog. The bowden tube may be damaged or there could be debris or residue in the tube. Go on Amazon and order a new blue capricorn tube and fit it to the printer using a how-to youtube video. This should fix the problem in this case.

The tube is brand new.


text:
OpenSCAD ERROR: Current top level object is not a 2D object
I have created a Mengersponge in OpenScad which is a 3D object. I wanted to get an SVG export from it for the laser cutter but I receive this error:"Current top level object is not a 2D object." How do I select each side of this sponge to export it as SVG for laser cutting?
Code:
module MengerSponge(side = 270, order =3){
    difference(){
        cube([side,side,side],center=true);
        MengerSponge_aux1(side, order);
    }
    }
module MengerSponge_aux1(side, order){
    rotations=[
    [90,0,0],
    [0,90,0],
    [0,0,90],
    ];
    for(rotation=rotations){
        rotate(rotation)
    MengerSponge_aux2(side, order);
        }
}

 module MengerSponge_aux2(side, order){
     if(order>0){
        translate([0,-(side-(side/pow(3,order-1)))/2,0])
            for(i=[0:pow(3,order-1)-1]){
                translate([0,(side/pow(3,order-1))*i,0])
                    translate([-(side-(side/pow(3,order-1)))/2,0,0])
                        for(i=[0:pow(3,order-1)-1]){
                            translate([(side/pow(3,order-1))*i,0,0])
                                cube([(side/pow(3,order)),(side/pow(3,order)),side+1],center=true);
            }
        }
        MengerSponge_aux2(side, order-1);
     }
     else{
         echo("Fail");
     }
 }
side=270;
order=3;
MengerSponge(side, order);

```

Use the projection() feature of OpenSCAD to effectively generate a plane cut. Position the cube structure in such a manner that the x/y plane intersects the desired shape to be exported. Rendering the code will then generate a 2D image. Previewing the code will generate a 1 mm thick 3D model which will "flatten" when rendered.
For the image below, I did not translate the cube, merely placed the cube generation within the projection feature.
projection(){
MengerSponge(side, order);
}

This rendering will export to SVG as desired. Different positioning of the cube (rotate, translate) will create different patterns.

Don't forget cut=true

I did forget that, yet the result is "acceptable," yes? What is the failure mode of forgetting it?

Without cut=true, you get a 2D shadow of the part, not a 2D cut (union of all cuts as Z ranges over -infinity to infinity).

That's useful information. Is there a link to an example model in which both circumstances are provided?

In tthe manual I linked to, no?


text:
What are viable substitutes for Raspberry Pi to run Octoprint or similar software for Prusa i3 MK3S+?
Where I live, Raspberry Pi is currently* either unavailable, at prices 3 times higher than a year before, or sold online as "untested". Or straight up as not working. So I am not getting one.
At the same time, I'd love to be able to set up Octoprint or similar platform. Are there any alternatives that are not like out of stock worldwide? What I'm looking for is:

Ability to send prints using wireless network
Ability to monitor prints using webcam / embedded camera
Ability to monitor temperatures, get filament runout alarms etc
Ability to stop print in case of a fail

* end of 2022

https://all3dp.com/1/best-raspberry-pi-alternatives/

@0scar this list is useless. All of the boards listed costs 2~3 times more on Amazon that it says on the list. If at all available. Thus, these are not alternatives to the Raspberry Pi. They are just as overpriced and hard to get as original.

Would https://github.com/luc-github/ESP3D work? You'd need a serial port on the printer, rather than USB, but perhaps you could use this for a print controller and an ESP-Cam board as a camera. It would be about $14 in hardware, all told.

I use an orangepi to run octoprint. Works great

A recent post on Reddit directed me to a possible alternative. The link given was for a YouTube video titled "Armbian, Octoprint and Octodash install on Libre Renegade (Raspberry Pi alternative board)" from The feral engineer.
The single board computer listed in the video is the Libre Computer Board ROC-RK3328-CC available on Amazon (US) for $50 USD.
The feral engineer did mention that he had a few problems getting things to work but was successful in the end. He does give the major steps for doing the installation and overcoming some of the errors that popped up.
For a list of all possible single-board computer (SBC), module (SoM) and Linux-supported development boards see Board-DB.

Another alternative I have recently come across is the Makerbase MKS  Pi Board. It is sold through Amazon (85 USD) and Aliexpress (55.79 USD) and is a great alternative due to the Raspberry Pi shortage.
The MKS Pi can run a standard Armbian OS but Makerbase supplies an OS image with klipper and kiauh baked in. An install tutorial by 3DP and me provides easy-to-follow instructions. This SBC is probably the easiest to setup.

Good point. Sadly, this board is "currently unavailable" at the link you posted and in shops in my country.

@Mołot I have added another possible alternative.


text:
Convert model to "skeleton / prototype" model for quick real world "Proof of Concept"
Does anyone know of a method, app, technique to "dumb down", if you will, larger models to do a quick initial print to check that it fits the real world proof of concept that it was designed for.
I am not talking about 0.3 mm draft printing, I already do that... But is there a way or method, to kind of "skeleton" the large print, print it in let's say, 25 % of the actual time to test its physical application. Scaling down works, in some situations, but I would prefer a 100 % model, just "simplified / skeleton'ized", still with the correct dimensions.
I primarily use Fusion360 for designs.

There are techniques to remove material from an exiting model to create less dense models (like in a skeleton). One such a technique is applying Voronoi tessellation (also known as a Voronoi decomposition, a Voronoi partition, or a Dirichlet tessellation), basically the model is broken up in polyhedrons of which the ribs are kept with a certain thickness and smoothed. See e.g. the following example from https://www.voronator.com/:

You can modify files yourself or use an online application to do that for you.
However, you may create skeleton like models, but it is not always faster to print these models; they may have less material, but retraction may cause the printing time to be actually longer than printing the original at low density infill.


text:
eSun PETG outer wall delamination, random huge artifacting on some sides and fine printing on others
Check this post for larger versions of these pictures,

Using an Ender 5 Pro, printing at 0.28 mm lowest resolution.
As per that subs recommendation, I've tried the following with not a shred of difference:

Different speeds down to 40 mm
Temps from 230-250 °C
Fans from 0-50 %
Calibrated E step
Changed retract before outer wall to off
Outer wall flow 105 %
Main flow to 105 %
Top skin overlap to 50 %
Ironing on
Retrimmed Bowden tube
New nozzle
Cleaned out hot end
Relevelling
Also happened directly after dehydrating

Seems to be something completely transient to these settings as it happens in the same place every time regardless. Are these under-extrusion spots? Should the PETG have a bigger baby-stepped Z gap?
Also seems like the first layer and other layers print what should be a straight line into an angled line (see top delamination). Completely stumped.

You want our assistance, but you expect us to go to reddit to see your images?

Kyron, welcome to 3DPrinting.SE. Please note that SE sites are not regular forums, it is just questions and answers. A question must therefore need to contain all the information we need to answer it, linking to a forum for the images is not allowed, SE has its own dedicated Imgur web server where it stores your images as long as the SE sites live when you embed the images through the image button above the text editor of your question. We've embedded the images for you.

Go a lot slower. 40 mm/s is near the max speed for PETG on a stock Creality bowden extruder at 0.2 mm layer height. You're aiming for nearly 50% more flow per unit distance, so you need to drop speed proportionally, down to about 25-30 mm/s.
If your problem is isolated to only certain spots, it's likely that those are the only spots where you actually achieve and maintain the requested flow versus slowing down and speeding up over and over. It's also possible that you have oozing during travel (especially travel inside the boundary of the part, if your slicer is doing that unretracted) or that the extruder is slipping during unretract, producing missing extrusions.


text:
Ender 3v2 is only recognized by Windows 10 laptop upon bootup
This might be considered a "Windows" question, but since it only happens with the Ender, I thought I would post it here.
I have a Windows 10 laptop connected to my Ender 3 V2, and I use Pronterface to control the printer. When I boot my laptop with the Ender turned on, the device is recognized, appears as COM4 in the Device Manager, and all works fine.
If I disconnect or turn off the printer with the laptop on, then reconnect it (or turn it back on), the USB does not recognize the printer and I have to restart my laptop for it to work again. Going into the Device Manager and trying to "Find new hardware" has no effect.
Stock firmware on the Ender with the CR touch (32-bit board).
Any trick to getting the laptop to recognize the Ender once booted up?


text:
How to apply manually obtained mesh leveling values to a G-code file on a printer without ABL?
I have a Raise3D Pro2, which if you are not aware, is one of the most overbuilt, overpriced printers that lacks some of the most basic features of an Ender costing 1/10th the price. One of which is ABL.
I wish to generate a mesh with a dial indicator temporarily attached to the carriage, and then apply that mesh to a G-code file.
How would one do such a thing once they have manually recoded the offset values for their grid?

Hello Benram, I've updated the question to temper the frustration ;-), I imagine you are not happy with the printer, for such a price I would have selected the Ultimaker instead. I hope you know what firmware the firmware of this printer is based on?

That was intentional. I wanted anyone who reads this to understand why they should never buy one of these!

That depends on the firmware, e.g. Marlin firmware can set a mesh through G-codes when the firmware is set to Unified Bed Levelling (UBL).
However, Raise3D is using a closed source of which is unknown on which the firmware is based. You can most probably not use the Marlin firmware commands.
If you want to adjust for a measured build plate surface geometry, you can always fall back on developing a software program to alter your created G-code source file.
If you map the surface you can describe the height as function of X, Y coordinates. The current height value should be compensated for that mesh. A relative simple program (or plugin, e.g. Python script) should be able to alter the first 10 mm of G-codes where you smooth out the mesh to zero compensation at 10 mm height. Basically this is what the Marlin firmware does, compensation for the surface geometry.

Thank you for the suggestion. A great idea, but I was hoping someone else had already coded such a script. Given how much hate there is for this model's shortcomings from other users, it would be the logical course of action. While it is technically simple and within my coding skills, I do not have the time to tackle such an endeavour at this time unfortunately. I will likely not keep the printer.


text:
How to horizontally align sketches in fusion360?
I'm working in fusion360. I have 5 circle sketches that I need to all line up in a vertical line. I tried setting constraints, but they were just putting the circles in the exact same x y positions. I just need each circle to have to same x coordinate.

What is the relationship with 3D printing?

Hi and welcome to SE.3DP. Unfortunately, questions about 3D software are off-topic, unless the resulting model is going to be printed - please see the CAD section. It may seem unfair, but we just can't support purely 3D software questions. However, if you were using Blender, then there is a Blender StackExchange, but there is not one, unfortunately, for Fusion. TBH, I'm really not sure where on StackExchange that questions about 3D modelling are on topic.

If SE is not a requirement, https://www.reddit.com/r/Fusion360 may be of value in this case..

Or maybe SE.Graphic Design - 3D. Or SE.Engineering - CAD or SE.Engineering - Solidworks.  See Where can questions that are purely about 3D modelling, or CAD, software be asked?


text:
Is my RAMPS 1.4 board fried?
I was adjusting the current on my Pololu stepper drivers when I accidentally fried two of my stepper drivers when I accidentally shorted the contacts with my multimeter probes. When I changed the fried drivers the board wasn't working properly. My Arduino Mega works fine alone when connected to my PC and executes the codes properly. However, as soon as I plug the RAMPS shield into my Arduino, the board disconnects from my computer. I cannot figure out the problem.

Hi and welcome to SE.3DP. Which version number of the RAMPS board do you have? Exactly which contacts did you short? A photo or diagram might help to describe the issue better. Please [edit] your question and add a photo/diagram, the contacts that were shorted and the version of the RAMPS board.

It is quite likely that something else (other than the stepper drivers) on the RAMPS board (and maybe even the Mega) has been damaged as well... The Mega board may still execute code correctly but maybe a random component has been damaged that you won't notice until it gets used.
It most probably would be possible to test both boards to locate the exact issue and faulty component, given enough time and patience.
The best thing to do, initially, is to look closely for any component that looks shot/burnt, or smells bad. It may sound odd but smelling a board can sometimes (but not always) locate the general area where a component has failed.
Another (more logical) approach would be to look at the schematic of the RAMPS to follow the circuits connected to the contacts that you shorted. Then check the components along that path. This method often is the most fruitful.
Assuming that you have a RAMPS 1.4 (you don't specify which version you have), there is the schematic:

However, even if you are lucky enough to locate the damaged component, do you have the skills to replace a SMD component?
Sadly, to be honest, it is probably cheaper, easier and quicker to just first buy a new RAMPS and substitute that in. The test to see if everything works OK. If the issue is still not resolved, then buy a new Mega and repeat the test.


text:
Why the extruder is making this noise? CR10 Smart Pro
The extruder makes a weird sound like moving an old door without an oily hinge - both when advancing or retracting.
This video shows the problem:
https://www.veed.io/view/055d1724-838a-48d1-98d7-8eaf3076ea2b?panel=share
I did everything, but the noise was still there.
Everything seems OK. I am trying to figure out what I should do. I took pictures from inside the extruder and shared them below.

What kind of sound? Can you describe it? Is it only when advancing? Retracting? Both?

@Davo Thanks for your reply. I recorded a video and shared the link in the question. Both of them, It makes a weird sound like moving an old door without an oily hinge.

The video does not appear to load for some reason on my browser. If you put the video on youtube, you can then embed the video into your question, which would make it easier for people to view, and then possibly provide you with a solution.

Has it always made the sound? If not, what caused the sound to start? What actions may have caused it to start? You say that you've tried "everything" - could you list what those things are, to save people suggesting things that you've already tried. Have to tried loosening, or tightening the screw? Oil is probably not a good idea as that can damage filament (see Is lubricating filament a good idea?). Please [edit] your question and put any additional info there and not in the comments.


text:
very bad surface quality
I am getting very bad surface quality on an Ender 3 Pro.
My last prints are a disaster like in the picture. The filament is PLA.
How to improve from here?
For reference: the filament was bought a few days ago and I did not dry it. I am using a 0.4 mm nozzle at a temperature of 215 °C. Speed is set to 50 mm/s.

Consider to edit your question with specific settings such as speed, nozzle and bed temperatures and if you've recently dried the filament. Underextrusion appears to be the result, but the causes are varied.

Please comment on the filament diameter in the slicer you used and inspect the extruder of the Ender, it has a poor extruder design, please look for gear wear or broken lever, the latter is common for these extruders.

You might want to increase the flow rate, 215C is towards the end of the range for PLA check the spec sheet. If all fails make sure nozzle is not clogged.


text:
Under extrusion with Ender3
I'm having some problem with my Ender 3. I have been printing for almost a year with good results. Then, all of a sudden, the fan started to be noisy and the prints came out definitely not good.
From what I understood looking around, the problem could be under extrusion.
I replaced the fan (both of them actually) but the prints keep coming out badly. The software is always the same (Cura) and I never changed any parameter whatsoever.
This is what I tried so far:

printing with (four) different filaments (always PLA though).
changing the E-steps
unclogging and replacing the nozzle (twice)
re-calibrating Z like a million times
printing different projects, included those who I already successfully printed before

-> Nothing helped!
Then I was forced to also change the software (because my PC died...) But even with the new version nothing changed.
Now the extruder calibration is okay (I print 10 cm and 10 cm of filament are consumed through a hot nozzle).
Increasing the flow by 5 % and the temperature by 10 °C (I'm now printing at 220 °C....) actually gives better results (the calibration cube is more definite and more solid) even if under extrusion is still appreciable.
Calibration cubes:

Printing example:

I don't know what else to try!!!
Can someone help me?

Hi, welcome to 3DPrinting.SE! Indeed, under extrusion seems to be the problem. From the second image it looks as if the print started out fine, but under extrudes in the upper regions. The images aren't very clear. How did you test the extruder calibration, with or without nozzle?

It's just because of the picture...under extrusion is present from start to end :( i tested the calibration with nozzle

You are pushing 10 cm through a hot nozzle for calibration, this is sometimes different in terms of pushing it under load (back pressure from the deposition/squishing of the filament). Although the correct calibration, the prints are under extruded, so there is too less filament delivered to the nozzle.
This hints to a problem with the extruder; these type of extruders are known not to be the best type of extruders, common problems with these extruders are a lack of idler wheel tension, broken and cracked extruder lever and wearing out of the brass extruder gear.
You should closely check the extruder during printing, it is expected that not enough filament is pushed forward to the hot end. You could increase the tension on the lever, but is is probably best to invest in a better Bowden extruder, preferably using a dual gear and/or using a gear ratio (for more torque). Note that you may require buying a new stepper motor as well: Problems with stock gear with no screw on Ender 3 pro.

In addition to checking for a broken or improperly tensioned extruder, I would also recommend just checking the brass filament gear and cleaning it. It tends to get caked with a mix of dust, filament shavings, and whatever else they absorb out of the air - maybe even oils from the nearby Z leadscrew or motor bearings, etc. - and this significantly reduces the effective tooth depth and thus grip. The soft brass teeth might even wear down.
If it's just dirty, cleaning it could solve the problem, but if it looks like it's worn and needs replacement, replacing the whole (very bad) extruder would be a better option. No sense spending money on just the gear when pretty much everything about this extruder is bad, and for not too much more cost, you could get a better one.

I can think of the following causes:

if the thermistor and heater in the hot-end is loose it can lead to weird results due to inconsistent temperatures.
the gear grip for the filament feed might be slipping and lead to inconsistent feeding and print outcome.

Hi Alex and welcome to SE.3DP. Without wishing to discourage you, seeing as this is your firat post, these seem more like questions requesting more details that really should go in the comments, rather than a definitive answer. If you could [edit] your post to turn the questions into actual statements of fact (which serve as answers) then that would be great. Otherwise, you answer may be converted into comments under the question. Thanks.


text:
Stronger connection (thicker point) between two lines
I've just bought my first 3D printer, and I've started playing with it. But apparently, I have the problem that the raft won't stick. I mean, it sticks, for iteration (layer) or two, and after that it just disconnects. This is what I've checked until now:

Bed is leveled properly, including Z, tried different variation of offsets
Temperature of both bed and nozzle are okay (70 and 210 °C, it is PLA filament)
Received slightly better results with adhesive for 3D printers, but still not ideal

Now, I've came up to the idea: I would like to try to interconnect each line in one layer (iteration) with thicker dot of melted filament for better adhesion. Unfortunately, I don't know how to setup this parameter in slicing software (Cura). Does anyone eventually know where I can find this parameter in Cura? In addition, here it is the extract of the GCODE:
;FLAVOR:Marlin
;TIME:8750
;Filament used: 3.97836m
;Layer height: 0.15
;MINX:45.401
;MINY:52.901
;MINZ:0.36
;MAXX:154.6
;MAXY:147.099
;MAXZ:31.035
;Generated with Cura_SteamEngine 5.2.1
M140 S45
M105
M190 S45
M104 S210
M105
M109 S210
M82 ;absolute extrusion mode
G28 ;Home
G1 Z15.0 F6000 ;Move the platform down 15mm
;Prime the extruder
G92 E0
G1 F200 E3
G92 E0
G92 E0
G92 E0
G1 F1500 E-6.5
;LAYER_COUNT:199
;LAYER:-7
M107
G0 F7200 X49.177 Y57.705 Z0.36
;TYPE:SUPPORT-INTERFACE
G1 F1500 E0
G1 F1350 X48.447 Y58.574 E0.05124
G1 X47.809 Y59.466 E0.10075
G1 X47.23 Y60.43 E0.15151
G1 X46.778 Y61.31 E0.19618

...

;TIME_ELAPSED:8750.646320
G1 F1500 E835.92386
M140 S0
M104 S0
M140 S0
;Retract the filament
G92 E1
G1 E-1 F300
G28 X0 Y0
M84
M82 ;absolute extrusion mode
M104 S0
;End of Gcode
;SETTING_3 {"global_quality": "[general]\\nversion = 4\\nname = Normal #2\\ndefi
;SETTING_3 nition = custom\\n\\n[metadata]\\ntype = quality_changes\\nquality_ty
;SETTING_3 pe = fast\\nsetting_version = 20\\n\\n[values]\\nadhesion_type = raft
;SETTING_3 \\nmaterial_bed_temperature = 45.0\\n\\n", "extruder_quality": ["[gen
;SETTING_3 eral]\\nversion = 4\\nname = Normal #2\\ndefinition = custom\\n\\n[me
;SETTING_3 tadata]\\ntype = quality_changes\\nquality_type = fast\\nsetting_vers
;SETTING_3 ion = 20\\nposition = 0\\n\\n[values]\\ncool_fan_enabled = False\\nin
;SETTING_3 fill_pattern = grid\\ninfill_sparse_density = 80\\nmaterial_print_tem
;SETTING_3 perature = 210.0\\nretraction_hop_enabled = True\\nspeed_print = 60.0
;SETTING_3 \\n\\n"]}

Is 70 Recommended for the bed? We used to print PLA with the bed at 40.

Yep, 60 to 70, according to the specification. :)

Which printer do you have? PLA should print very easily, 70 bed is quite hot, and generally PLA doesn't need a raft.

It is some Voxelab... You think I should try it with lower temperatures on bed? I will give it a go tomorrow on both 40 and 50 degrees, and will inform you about the outcome.

After some "experimenting", I've managed to resolve the problem. There were several contributors to the problem I had:

I had to replace the slicing software; My printer did not accept G-code from Cura perfectly, even after a detailed configuration of Cura, according to my printer specs. Instead, I've downloaded and used OEM slicing software (in this case Voxelab)

Printing speed was too high; With printing speed reduced from 60 mm/s to 40 mm/s situation significantly improved. Apparently, the extruder could not keep up with filament delivery at higher speeds

Increased PLA temperature to 230 °C.; This also partially resolved the filament distribution problem. Bed temperature remained at 60 °C, with quite good success (I've used adhesive as well)

Your work-around is a description to resolve a problem without resolving the problem. A properly tuned 3D printer will place the first layer on the bed (without a raft!) in such a manner as to allow the entire print to be completed.
Consider to print a single layer rectangle created in any software with which you are comfortable. A rectangle of 100 mm square would be large enough for analysis. Also, edit your question to reflect the current layer thickness and speeds you are using.
The single layer should present uniform width as the filament is applied to the bed. Each adjacent "stripe" should have minimal overlap with the previously applied stripe. Too much overlap (excessive extrusion factor) will create bulges between stripes. Insufficient overlap will result in gaps.
This rectangle print will provide feedback for your bed leveling as well as the z-offset. Excessive z-offset will reduce the grip of the filament to the bed.
Using adhesive and having poor results leads me to suggest the first layer is at a too-high z-offset, but your test will provide a better answer.
Even though I've seen a few references to PLA not requiring drying, PLA and other filament types can have problems with bed adhesion if there is too much humidity absorbed into the filament. Consider to dry your spool for four to six hours to see if improvement will result.
Lastly, you should not need to use a raft, unless a specific aspect of your model requires it. I've seen rafts "required" in low quality, low cost, low performance 3D printers with poor bed planar characteristics. One will hope your printer is not in that category.

Thank you for extensive explanation/comment. I've tried variation of lower temperatures on bed (40-50) + few more calibrations of the bed (with accent on z-offset). It did not help. In addition, I've updated my question with part of the GCODE and settings that could eventually help to demistify the problem.


text:
Design Considerations for Large Overhangs
When designing for 3d FDM printing, I'm wondering what is best practice for items with large overhangs which cannot have (or would be fairly impractical) support structures. Consider my following design:

This item is about 7" long, and you'll notice the narrow slot running through the middle of it. The slot is 0.100" wide.
I was about to print this when I suddenly realized printing it would be a problem. So I started messing around with painting on supports, but since something slides in this slot, I would have to do some extensive cleanup to make sure it's smooth.
What I ended up doing was splitting the body at the start of the overhang, and placing some alignment pins in the body (with corresponding holes in the upper portion of the body. e.g.

I will print the top and bottom separately and glue them together.
My question is whether this is my only option or if I'm missing something in the design process which might work better? This design is in Fusion360, in case that matters when discussing some specific tools that are available which I'm unaware of.

Note also that FDM™ is registered to a specific company. The generic equivalent is FFF.

When constructing a model intended to be 3D printed, your approach is sound. Overhangs and the required supports can be a severe problem and I believe your assessment is accurate.
The complexity of the upper portion would make printed supports an inappropriate path for the reasons you've provided, while your solution eliminates all the negative aspects of this model's construction/design.
The split as presented turns an excessively supported print into two completely unsupported, easily-printed sections. The alignment pins are the perfect approach as well.
You've not indicated an aversion to adhesive, another plus in the overall assessment. Printing the model(s) in the orientation displayed is going to provide the most strength from the plastic. In some models, one can change the orientation to eliminate or reduce supports, but too often the layer direction change results in a weaker object. Your split design removes that factor as well.

Thank you for the feedback. Is there a preferred adhesive for this? I'm using PLA. I was able to print successfully and glue these two together with CA glue, medium viscosity, using accelerant. There isn't any (shouldn't be!) any stress across the joint, but am interested if there's a better solution for other projects.

My experience with CA products is that they become brittle and fail over time. If the part is not experiencing any flexure, it may be sufficient. A "goo" type adhesive may be preferable if there is flexure. One such product is E6000, also ShoeGoo. It's fairly viscous (gooey!) and bonds well after 24 hours.

@fred_dot_u I personally prefer epoxy type adhesives, as I experienced that most "universal glues" are horribly inadequate to do any gluing.

While slicing into slabs and the use of alignment pins is a perfectly viable solution, including the alignment features organically into a single print can make assembly faster. In this case, the model itself acts as an alignment feature or might even act as the clamp, at the cost of creating a more complex cut. An additional benefit of a more complex cut is the elimination of separate alignment pins and getting the glue surfaces away from parts that need a critical dimension
As an example, I used an approximation of your model and shifted the cut layer around some (more complex) to get a natural left-right alignment feature from the deep cut, and then added a high "peak" on the model to act as a front-back alignment feature. The yellow faces ensure alignment in this case, and the red faces are main glue faces.

Also, keep in mind point orientation can alter things a lot: printing on the "back" as we both modeled, the slot needs support. However, there is an orientation that remove the need to support the slot's top and instead only requires support in the pocket, possibly eliminating the need for a two-part print at the cost of needing to remove the support in the area marked red, but which, as a pocket without undercuts, should be decently easy:

Pretty cool solution and will keep that in mind in the design process. I found adding the pins after the fact just a 60 second mod to the design. As far as printing vertically, I contemplated that, but wanted the 'door" which slides in the slot to run parallel to the print layers to reduce friction as much as possible. It also would add time and filament to the print. Might have been a little to cautious on my end, however.

@LarryBud that's a valid consideration, smoothness of the slot and post processing time. The main point was to remember that it is something you should think about. See also https://3dprinting.stackexchange.com/questions/6726/what-special-considerations-must-be-taken-when-designing-parts-for-3d-printing/6830#6830

If your end product allows it, one possible solution would be to remodel your part so that instead of having a square channel in the center, the channel had sloping or curved sides so that the overhand was removed, and then to print out an infill piece that could be clotted into the channel to square it off.
In essence, you would turn the square channel into a triangular notch with shallow sides that didn't need supporting, and then you restore it to being square after it's printed.
This would also have the advantage of meaning that you could print the infill to a much higher standard than the rest of the print, so it was stronger.


text:
Ender 3 Pro Direct Drive weird/small blobs?
I have an Ender 3 Pro with the direct drive upgrade, aluminum extruder (The same problem happened with the plastic one), double-sided bed default black on one side and PEI on the other (Happens with both), aluminum adjustment knobs for bed with better springs, and upgraded spool holder with ball bearings.
Things I have done to try to fix this:

Add aluminum extruder
Upgraded spool holder with ball bearings
Calibrated my E-steps
Upgraded firmware
Stopped using OctoPi
Switched build surface (The only one that I could try that I have on hand is glass but that didn't work the last time I tried it)
Tightened belts
Printed calibration cube
Printed temp tower
Printed retraction tower
Printed retraction speed tower
Looked up YouTube videos
Cleaned motherboard (There was dust in there)

Those all failed and I have no idea what this is or how to get rid of it, please help.
Settings:

Layer height: 0.2 mm (I haven't tried a different layer height)
Print speed: 40 mm/s (I have tried slower/faster)
Nozzle temperature: 195 °C (I have tried higher)
Infill density: 15 % pattern: cubic (I have tried different infill patterns and density)
Cooling: 100 %

I'm afraid there is literally nothing else I could possibly do at this point except replace/tune mechanical parts, which I have tried.

UPDATE: I have determined that the problem has something todo with infill. If I change the infill then the problem also changes (Like the pattern on the surface changes) I'm currently trying different infill patterns to see which ones yields the best results.

What settings do you have on the shell? The shell should always be multiple of the nozzle diameter. Also what nozzle size you're using and which slicer. Depending on the slicer there are some settings that like print shell before infill and infill overlap.

@LostKatana, can you explain what you mean by this? In PrusaSlicer, vertical shells are a quantity, not a distance. On horizontal shells thickness, it should be a multiple of the layer height, not nozzle diameter, right?

I am using Cura Slicer; and did you mean walls? I've tried 2, 3, 4 walls and it still looks the same.

@LarryBud I'm not familiar with PrusaSlicer, but the shell/wall should be a multiple of the nozzle as e.g. Cura calculates based on the thickness how many (wall line count is the setting name) it needs and will adjust gcode accordingly.

AdamSalem yes, in Cura it is called walls. Is this effect on all sides?
Your wall settings would be helpful here. I have a .4mm nozzle and usually print with at least 3 walls. I have not faced this so far.
What you can also look up is the Infill overlap setting, maybe this has been modified by accident.

Do you print the walls first, or the infill? As far as I know, such patterns can come when you're printing the infill first, so if you do, maybe try the opposite way. The next reason I can imagine are retract settings or vibration issues.

I tried both printing infill first and walls first.

I bought a TL smoother which fixed the problem!

It would be beneficial to future readers if you could explain what TL smoothers are and how they fixed the problem.

TL smoothers only work for DRV8825 drivers, so the question is, do you have these drivers?, else there might be a different solution, or did you print the exact G-code file. Please expand the answer to include more information.

This seems plausible even with the A4988s in a classic Ender. Without reduction gearing, the E motor only has 5.8 full steps per mm of filament moved. 1 mm of filament is about 30 linear mm of extrusion, so you get a full step about every 5 mm of motion. If microstepping linearity is poor (and it's likely to be poor under the high holding torque needs of a direct drive extruder) you'd expect to see this kind of oscillating extrusion.


text:
How to quantify the dividing line between choosing a driven lead screw system vs. driven lead nut system?
In a 3D printer (or any other CNC application really) where a lead screw is part of a motion system, there is a design choice to be made. . .

Drive the lead screw, having the lead screw nut fixed in place.
Drive the lead screw nut, having the lead screw itself fixed in place.

There are "claimed" pros and cons to each path. Specifically, driving the lead screw is mechanically far simpler (install a flexible coupler between the motor and lead screw, and you're done!) but has apparent problems with accuracy because of shaft wobble, as well as speed because of fighting high rotational inertia. Driving the lead screw nut, on the other hand, is mechanically more complex, but has a fixed (supposedly low!) inertia for any lead screw lengths as well as more manageable wobble characteristics. (It should be noted at this point that most professional, high-performance systems do indeed drive the lead screw nut.)
Operating under the above ostensible wisdom, I was planning a new 3D printer build based on the concept of a lead nut drive. While making an efficient and affordable parts list, I was noting that the taper bearings I found most reasonable to use to make the nut drive, as small as they are, are still quite the mass of steel. Furthermore, the diameter of the rotating bearing mass is quite a bit larger than my preferred lead screw diameter. Since I would assume the radius squared term in the equation for rotational inertia takes some kind of key stand here, and my lead screws themselves could be any conceivable length, I started to question the wisdom that it's "always" more performant to drive the lead nut.
An extreme counter-example is if one used something like two sets of LM67048/LM67010 cone/cup pairs, where a single cone weighs in at >100 g, and has an outer diameter of >16 mm, which ends up being >200 g of rotating mass just in bearings (accounting for two cones), plus the rest of the nut weight. Then, combine this with 300 mm of 8 mm lead screw, which may only weigh ~90 g, and suddenly it just doesn't feel like it would be easier to abruptly accelerate all that nut hardware than it would to just drive the lead screw directly.
I'm at a minor impasse here, because I don't know "for certain" how to go about making the decision in a clear and quantifiable way. Should one just multiply the mass by the diameter squared, to get the rotational inertia, and use that as an apples-to-apples comparison across any body we may want to rotate, i.e. taking the smaller number as the winner? Is that good enough?

Unless the screw is straight you will always have a wobble, whether you drive the screw or the nut. If it accuracy you're after install ball screws, preferably the ground ones and use double nuts, but those are pretty expensive...

There is a distinction between "deflection" and "wobble" that needs to be made. Say I have 500 mm of 2 mm pitch lead screw, and it is bow shaped, dipping down an insane 10 mm in the center, then coming back up to true zero. Turning the lead screw enough to travel 100 mm (especially near the center) is going to REPEATEDLY attempt to cause 20 mm off axis motion. On the other hand, turning the lead nut over the same area will simply have a constant 10 mm deflection that is off axis. Neither would be great, but one is clearly less desired than the other.


text:
Metal insert of 3D print with solder cup
These are metal inserts for 3D prints:

What I want to do is use them as a connector. A metal pin will insert them (the male connector) and it will have contact with the metal inserts.
I just want to have connectivity with a PCB as well, via soldering cables.
So my question is, are there metal inserts that have outputs where I can solder wires?
Or, maybe metal inserts that end up as a solder cup?
For reference, these are solder cups:

EDIT:
Perhaps if i add the dimensions of the male pin, it can make the process of answering easier.

The male pin is 2.3 mm wide and 6mm high.

The metal-parts tag is for casting from printed positives or molds or direct metal printing. you are asking about post-processing.

You are looking for heat-insert female sockets...
JST-connectors don't exist as heat set parts, but you could include a void for the socket to go in.
You can buy DuPont-style cups that lead to a thin pin, which then is pushed into the female connector. Those contain a piece that acts as a spring to ensure good connectivity. Those female connectors don't exist as heat-set but can be bought without a plastic shroud for mounting in your own hardware with defined holes by physical interaction with the shell.
What you want is an insert that is not threaded but has one or more springs on the inside that press on the pin, akin to a phone connector shown below, where the metal "legs" connect to the different sections and one at the base acts as locking. The most simple design of this type would be a mono plug that also offers ground and a way to give a solid connection between the parts. However, the design of the needed springy bits inside makes it impossible for these to exist as a heat-insert - you can't heat these evenly or melt a path.

The only way to ensure good contact with a connecter that can be heat-set would either require the pin to screw into the insert, or the pin to be spring-loaded against a flat insert. The latter can be done by either using a solid metal slug as an inset or by retrofitting a normal inset with a screw that creates such a surface. However, spring-loaded connectors require some sort of physical interlock to get the parts in position and securely connected.

Thank you very much for your wonderful answer. Unfortunately, i did not understand many things. Your answer was great, it was my incompetence and lack of experience that made it hard to understand it. You proposed many solutions, but then you backed up because it was unfeasible. Which is the most practical way to do this? I just want my design to have female connectors. This proved to be a much harder problem than what i had originally imagined. PS, I edited my question with a picture that details the dimensions of the male pin (That will insert the female connector i want in my design).

@user1584421 none of the proposed solutions is a heat set part. The question what is best depends on the geometry of the surrounding part. If the pin needs to retain the connection and bear load, something like the phone jack might work. If it is a stress free connection that can be made a little before the parts are merged and separated after they are taken apart, JST works. If the connector can just get into position and then is arrested, spring-loaded flat connectors can work.


text:
Cut a Möbius strip in four parts with interlocking
I'm a beginner with OpenSCAD. I use to work with Rhino, but I have no more license and the new Fablab I'm working with uses OpenSCAD, so I'm learning OpenSCAD now.
The picture below shows what I want to do, I need this to be able to 3D print several parts to get a larger Möbius strip.

I found these scripts:
1.  /*
2.   * Möbius Strip
3.   *
4.   * r: radius of strip
5.   * w: width of strip
6.   * t: thickness of strip
7.   *
8.   * The model uses $fs to adjust the smoothness.
9.   */
10. module moebius_strip(r = 1, w = 1, t = 1) {
11.     step = $fs;
12.     for(azimuth = [0 : step : 360]) {
13.         x = r * cos(azimuth);
14.         y = r * sin(azimuth);
15.         translate([x, y, 0]) {
16.             rotate([0, azimuth/2, azimuth]) {
17.                 cube([t, step, w], center=true);
18.             }
19.         }
20.     }
21. }
22.
23. $fs = 0.5;
24.
25. moebius_strip(r = 30, w = 15, t = 1);

This one above is working and I found another one for the split :
module mycut() {
    translate([x,y,z]) cube([w,l,h]);
}

difference() {
    myobject();
    mycut();
}

translate([u,v,w])
intersection() {
    myobject();
    mycut();
}

I simply don't know how to use those scripts together. Can someone explain to me a little bit about how I can manage this? Don't forget that I'm a beginner!

This uses four different pieces.  For you purposes, would the resulting object be nicer if made with four identical ⅛ twist pieces?

Cutting to pieces
To cut the ring into pieces you can take the intersection() of the object and the quadrant of interest (e.g. using a cube, but a wedge would have worked as well).
/*
 * Möbius Strip
 *
 * r: radius of strip
 * w: width of strip
 * t: thickness of strip
 *
 * The model uses $fs to adjust the smoothness.
 */
module moebius_strip(r = 1, w = 1, t = 1) {
    step = $fs;
    for(azimuth = [0 : step : 360]) {
        x = r * cos(azimuth);
        y = r * sin(azimuth);
        translate([x, y, 0]) {
            rotate([0, azimuth/2, azimuth]) {
                cube([t, step, w], center=true);
            }
        }
    }
}

$fs = 0.5;

xloc=[0,1,-1,-1,1];
yloc=[0,1,1,-1,-1];
//quadrant = 4; // 1, 2, 3 or 4
for(quadrant  = [1 : 1 : 4])
intersection(){
    translate([xloc[quadrant]*10,yloc[quadrant]*10,0]) moebius_strip(r = 30, w = 15, t = 1);
    translate([xloc[quadrant]*10,yloc[quadrant]*10,-(30+15/2)/2]) rotate([0,0,(quadrant-1)*90]) cube(30+15/2);
}

Since tabs and slots are requested, we need to make some adjustments.
Add/subtract tabs to piece
All that is left to do is to cutout a "rectangular" shape at the interfaces. For that we glue or union() a tab on one side and extrude or difference() a tab on the other side, a wedge is used for the intersection() with a smaller sized width Mobius strip.
echo(version=version());
//debug = 0;
//explode = $preview ? 0.1 : 0.0;
//$fn = $preview ? 90 : 360;
//nearly_zero = $preview ? 0.005: 0.0;
tol = 0.01;
/*
 * Möbius Strip
 *
 * r: radius of strip
 * w: width of strip
 * t: thickness of strip
 *
 * The model uses $fs to adjust the smoothness.
 */
module moebius_strip(r = 1, w = 1, t = 1) {
step = $preview ? 2 : 0.5;
    for(azimuth = [0 : step : 360]) {
        x = r * cos(azimuth);
        y = r * sin(azimuth);
        translate([x, y, 0]) {
            rotate([0, azimuth/2, azimuth]) {
                cube([t, step, w], center=true);
            }
        }
    }
}

module wedge(h,r,a)
{
    th=(a%360)/2;
    difference()
    {
        cylinder(h=h,r=r,center=true);
        if(th<90)
        {
            for(n=[-1,1])rotate(-th*n)translate([(r+0.5)*n,0,0])
                cube(size=[r*2+1,r*2+1,h+1],center=true);
        }
        else
        {
            intersection()
            {
                rotate(-th)translate([(r+0.5),(r+0.5),0])
                    cube(size=[r*2+1,r*2+1,h+1],center=true);
                rotate(th)translate([-(r+0.5),(r+0.5),0])
                    cube(size=[r*2+1,r*2+1,h+1],center=true);
            }
        }
    }
}

xloc=[0,1,-1,-1, 1]; // vector indexed by the quadrant, negative value is the negative x-axis
yloc=[0,1, 1,-1,-1]; // vector indexed by the quadrant, negative value is the negative y-axis
offsetVal=0; // can be used to explode the view
quadrant = 1; // 1, 2, 3 or 4 resp. for xy, -xy, -x-y or x-y
//for(quadrant = [1 : 1 : 4]){ // now commented to used single single quadrant
    difference(){ // for extruding the tab
        union(){ // for adding the tab
            intersection(){
                translate([xloc[quadrant]*offsetVal,yloc[quadrant]*offsetVal,0]) moebius_strip(r = 30, w = 15, t = 1); // Mobius belt
                translate([xloc[quadrant]*offsetVal,yloc[quadrant]*offsetVal,-(30+15/2)/2]) rotate([0,0,(quadrant-1)*90]) cube(30+15/2); // quadrant cube
            }
            intersection(){
                moebius_strip(r = 30, w = 7.5, t = 1); // Mobius belt with smaller width
                rotate([0,0,(quadrant-1)*90]){
                   wedge((30+15/2), (30+15/2), 10); // intersect with wedge to get a tab that extends the quadrant piece
                }
            }
        }
        intersection(){
            moebius_strip(r = 30, w = 7.5, t = 1+tol); // Mobius belt with smaller width and increased thickness for better cutting out negative tab
            rotate([0,0,(quadrant-2)*90]){
               wedge((30+15/2), (30+15/2), 10); // intersect with wedge to get a tab that extrudes the quadrant piece
            }
        }
    }
//}

Note that this takes some time to render (F6), the preview (F5) didn't even show because of too much elements. Just change the value of quadrant = 1; to 2, 3 or 4 for the other segments.

Please note that the image from the question is not what is created with the Mobius script, to generate that object rotate([0, azimuth/2, azimuth]) needs to be changed to rotate([0, azimuth, azimuth])


text:
Vertical holes: round vs hexagonal
Please reference the following page on Thingiverse:
https://www.thingiverse.com/thing:5600770
This is an insert for a bandsaw (the replaceable part that the blade passes through in the middle of the bandsaw's table), with holes to allow for dust to fall down and also be pulled down by airflow from a shop vacuum or dust collector.
I am modeling my own version of this with my specific dimensions, but I thought I'd ask if it would be easier for the 3d printer to do round holes instead of the hexagonal ones.
(For reference, the printer that I have access to is a Prusa i3 MK3S+, with a 0.4 mm nozzle).
Edit: The fluidity of movement being better for circles is what I was expecting. When doing a circle, each small segment of straight line is only slightly different than the previous one, whereas the hexagonal hole would require abrupt changes. In my case, the final appearance is not critical since it's just to let dust fall through. The version with circular holes might be a bit stronger as it removes a bit less material. I used OpenSCAD to create the model, since my geometry is pretty straightforward. I was starting to mess around with FreeCAD (out of curiosity) but then I remembered that in OpenSCAD I used the trick of 'facet numbers = 6' to get the hexagons, so I just changed those to 60 (thank goodness for being able to define and use variables) to have the same placement of holes.

The printer isn't mine, it's in a public library and I don't want to abuse it so I will only print the one with circular holes.

similar: https://3dprinting.stackexchange.com/q/18603/8884

Consider to post your creation to one of the resources such as Prusa's Printables, especially if you'll include your .SCAD file. I may not need to create the bandsaw cover, but I would enjoy to see your OpenSCAD work, as I'm still new at it, six years after I've started.

The g-code that drives a 3D printer, with some exceptions, converts circles to multiple segments of straight lines, very short straight lines. There is going to be a greater amount of math to be performed on many circles, while one could consider that if the hexagonal segments are sliced in a suitable manner, the result is going to be more linear, with lower demands in the mathematics aspect.
That's one aspect of the difference. Another aspect is the fluidity of movement. You may get a smoother extrusion with the circles as the travel distance versus speed is going to be more uniform in creating a circle, while creating a hexagon will result in a speed change at the corner.
It's only one person's opinion, but I feel that it's half of one, six dozen of the other. You get a trade-off from the processing load with a hexagon, but you might get a better appearance with the circles.
If you are creating your own design (good!), would it be more difficult to create one of each? What program are you using to create this work?

Depending on your slicer and possibly printer firmware, there are ways to generate arc G-code that would make circular paths like this a lot more efficient. e.g. Cura or Octoprint plugins.


text:
My extruder failed. Is there any hope to recover print?
Yesterday I had filament that entangled on the spool and before I knew it, the printer told me to eject the filament. Unfortunately, then the filament broke. There is no way to fully unload it, no way to load new piece.
Long story short, I need to disassemble extruder-hotend assembly and fix whatever is broken. I'll manage, it's simple mechanical and electrical issue and I know my way around it. But, is there any chance to recover that print?
I'm lucky it failed at about the end of a layer. It's 0.3 mm layer height, so I can even use calipers to find out how many layers I do have. But how would I go about it now?
I used PrusaSlicer and the printer is a Prusa i3 MK3s+ so any specific guidance would be appreciated, but general guidance is also welcome.

In order to "resume" a failed print like this, you can edit the prints .gcode file accordingly.

Measure the height at which the print failed

Open the file, and search for when the printer starts the corresponding layer. How to search for this differs from slicer to slicer. In SuperSlicer, it's "move to next layer (XYZ)". Searching for moves to the desired Z height might work too, but beware of false positives if you still use "Z hop" for some reason.
You may want to choose the layer above the measured height as a starting point since the nozzle might scrape over the printed parts if you try to print the same layer again.

Delete everything from the line which moves the printer to the first layer up to when it moves to the layer you wish to resume printing from.
If you use mesh bed leveling, you'll need to remove that too - or the printer might probe into the existing print. If your start G-code contains moves that might make the print head interfere with the existing print, remove that too.
Also: Make sure the print head moves to the desired Z height before starting to move to the print area (on X and Y) - otherwise, it might again crash into the print.

Start the print as usual and pray.

You'll be likely to see some defects/imperfections on the failed layer, but the print as a whole should be salvageable in most cases.

It's utility print, I don't care about visual defects. Thank you!

I used Prusa Slicer and print is on prusa i3 mk3s+ so any specific guidance would be appreciated.


text:
RPi unreachable over network after bed leveling
I have a Raspberry Pi 4 running a complete instance of the RPi OS with few extras, although I usually boot to the terminal and not to the desktop. Primarily, my RPi is dedicated to running Octoprint for my 3D printer (a Creality CR-10 V3), which has worked great for a long time. With 8 GB of RAM and a 128 GB micro SD card, it's not like my device is constrained on resources, so I am unsure why the Octoprint server intermittently becomes unavailable.
Before anybody suggests it, as though I did something wrong, I should mention first that the Octopi image never worked well for me. I fought many noble battles against its mighty dragons before deciding I should ditch it. Therefore, I installed a standard RPi OS image and manually followed the steps to set up Octoprint. That was necessary because absolutely nothing I tried would prevent the WiFi connection from cutting in and out. I also have a solid power supply, so that's not the culprit either.
What makes this issue different than the WiFi issue I previously experienced is that my network connection on the RPi remains stable. Moreover, despite being unreachable (except locally), the Octoprint server has not gone down. I can also not connect via SSH, and the RPi no longer responds to pings. I verified this by attaching peripherals and loading the desktop. After becoming unreachable to my laptop, I confirmed that localhost:5000 remains available on the RPi, and there is an internet connection, so what gives? The server is up and running just fine.
Whenever this happens, if I am using Windows Remote Desktop, the connection there also goes down.
It seems like a firewall is blocking the connection, but that makes no sense. My anti-virus is not blocking it, and I don't see any firewalls in my RPi. To no avail, I already tried disabling the firewalls on my computer. The only thing that re-establishes connectivity, it seems, is restarting the RPi. But occasionally, it comes back on its own if I wait a long time.
There is a pattern here, though. The server/RPi becomes unreachable anytime I perform bed leveling. With some luck, connectivity sometimes comes back after finishing, but most of the time, it does not.
Version information:

Linux Raspberry Pi 5.15.76-v8+ (x64)
OctoPrint 1.8.6


text:
Steppers suddenly disabled during job
I'm using:

Workbee CNC
SKR1.4 Turbo with TMC5160
Marlin 2.0

Steppers suddenly disabled during job. But, they get back working as soon as you restart the machine.
I've had the problem twice with this setup. Once with the Z-axis and once with the Y-axis (that uses two steppers, one keeps on working while the other was disabled).
When I had the problem in Z-axis, I decided to lower current on that axis from 2 A to 1.9 A. It's already 1.5 A for both steppers on the Y-axis.
Just switching off and on the machine is enough to let steppers work again say it seems not to be a wiring problem.
Any clue? Any advice is welcome.

What steppers do you use? NEMA 17 or 23? A current of 1.9-2 A means you need to actively cool the stepper drivers!

did you check the G-code? Does the board feel overly hot?

Hi,
I'm using Nema 23. The one configured with 2A are bigger ones. Steppers are warm but not hot. I can hold them in my hand indefenitly so I assume it's not too much current for them.
G-code is as generated by fusion 360. It includes long movements on the Y axis as I'm making a guitar neck. Its quite intensive on the CNC. Much wood to be removed.
Heat sinks tend to be quite hot. I can keep a finger on the top for around 3 s. This says noting on ship temperature that might well have exceded a limit.
My guess is overheating of drivers. I'll add a big fan and I hope this will fix it.

Check if your stepper drivers are overheating. Driving a nema23 motor is no joke, and at a 2A current, the drivers could be getting a little toasty, tripping the temperature limit and disabling the drivers.

Quick update : I've added a 120mm fan on top to the BTT card. Everything sems cold now.
First I thought it was OK but I had it twice again with Z axis. I had it 5 times now. Only comes on long jobs (after at least 1 hour of precessing). Any clue is welcome...
Bernard

I think I fixed the problem.
Marlin was configured in hybrid mode with stealth chop mode at low speed then spread cycle when the stepper goes faster.
I removed stealth chop and set spread cycle at any speed and it seems to be OK.
I could let the machine work for hours with no issue

Nice to post your own answer, please don't forget to accept the answer! Thanks!


text:
Marlin bed leveling compensation not working
I have Ender 3 which I bought in 2018.
Thigs I have done so far to the printer;

Installed a BIGTREETECH SKR V1.3 board.
With TMC2130 drivers.
Flashed the new Marlin 2.1.1 (Configuration.h and Configuration_adv.h)
Installed and configured ANTCLABS BLTouch v3.1
Prints are sent through a Raspberry Pi 3b+ with OctoPrint 1.8.6
I have mounted the heating plate on standoffs (not on springs).
On top of the heating bed I have put a glass plate as my print surface.
Leveled the X gantry (as per this video).
Did the "probe Z offset wizard" (as per this video).
Did ABL Visualizer update.
Enabled baby stepping, but did not see an option when double clicking nor I see a menu item in "Tune" option.

Issue;
I'm having trouble getting my first layer perfect.
As the front prints are loose and back prints are squashed to the build plate.
Here is the first layer test print file.
If what I understood so far about ABL is correct, when printing with a uneven bed surface, the z height will be adjusted according the probed data. But in this test print looks like it is not being compensated.
Below is how my visualized bed mesh looks like (with those fixed standoffs).

0.7 difference is too much - tram it better!

Hi Hansa, welcome to SE.3DP. Nice question, and well presented

What can be read from the visualization of your bed geometry is that the left side (when facing the printer) of the X-axis is lower than the right side, so your plate is tilted.

If what I understood so far about ABL is correct, when printing with a uneven bed surface, the Z height will be adjusted according the probed data.

Yes, true (see Automatic Bed Leveling (ABL) with a sensor (BLTouch, inductive, capacitive), how does it work?), but that is a sales pitch, you don't want the bottom of every print to be skew! A probe is not meant for those skew plates it should be used for local dips and dents in the build plate. ABL (or UBL, see What is ABL or UBL? Is this the same?) will scan the geometry of the build plate, but you still need to supply a bed as level as possible. With the bed geometry results from the question, you need to level better! You should either shim the left side standoffs so that the bed is more level. A probe shouldn't have to compensate for the a skew plate, it can, but it should not. It is either wrongly trammed, or there is a hardware problem that is commonly found on these printers (X gantry is not parallel to the bed and has play, due to the cheap roller system and simple single driven lead screw design). This is described below (to make a more complete answer) so that other readers that run into similar issues can use this information
A possible alternative is that Looks like there is something wrong with your X-gantry, make sure the X-gantry is parallel to the bed, e.g. as seen in the following image:

This could be a result of lack of maintenance, considering the printer is from 2018, the frame needs to be checked. At the moment, the right side is closer (high X values), so either your bed is higher on the right side, but more likely (as you use fixed length stand-off's) the X gantry is tilting down on the right side (when facing the printer) and therefore reporting closer to the bed as if the bed is higher to the right, e.g. see adapted schematic:

This is a very common problem with the Ender 3 type, especially the single lead screw driven designs. To fix this permanently, installing a second lead screw is advised. As a quick fix, you need to inspect the complete roller system on both Z-axis posts and retighten them.
An excellent example of the problems with the X-gantry is shown in this video:

This video is a very good example for the problems with the portal style printers that use rollers for guiding the gantry. Look at the play in the (X-Z) gantry, this would cause the exact same bed visualization as posted in the question (note that the video is centered on the installation and software changes, but the printer used has seen better days and should have been maintained prior to installing bed leveling).

Hello @Oscar, your answer is very complete; however, for me the bed is well trammed, check it out https://i.imgur.com/EILFaJj.png there seems to be a little warp on the left side of the table, but thats what the ABL is for, right? Anyway my case is exactly the same as the OP, all the troubleshooting steps, same printer, same board with the difference that Im using a CR Touch instead of BL Touch, and my bed is well trammed. With all that, my Z rod doesnt move while printing 1st layer, I checked EEPROM to get the bed mesh and it was there, ABL was enabled. Do you know what could be the cause?


text:
Ender 3 Pro extruder skipping and knocking, tried multiple things
I recently purchased some MatterHackers Quantum PLA and began printing on my Ender 3 Pro. I successfully printed three times with no problem, on the fourth print about 2 hours in, the extruder started to skip and make knocking noises. The filament completely stopped extruding. I originally thought it was just a basic clog and I took steps to fix the problem:

I disassembled the print head and found a small bit of filament in the Bowden tube and cut the clogged piece off.

I cleaned out the heat sink and aluminum block of any debris

Replaced with a new nozzle

Tightened the spring on the extruder

I’ve checked the teeth on the extruder gear and they didn’t seem to be worn down
After all of this, I tried the same print again but printed at a nozzle temperature of 225 °C instead of the 215 °C I had it at originally, and it failed again near the same spot about 2 hours into the print.
Is there any advice I can get from anyone in the community as to why I’m having this problem?

Does another filament do this?

@DennisWilliamson no this was the first filament that it had happened on. Yesterday I tweaked the retraction settings and was able to successfully print the model with some stringing. I think the problem was mostly the model I was trying to print having far too many retractions in a certain stage of the print causing the filament to clog.

OK, I just wondered whether the filament had too much moisture.


text:
3D printing filament that can absorb photosensitive liquid
I'm a student artist trying to use 3D printing in my practice a bit. I'm working with liquid light, which is essentially a photosensitive liquid that you can apply to surfaces and later develop in the darkroom. I'm hoping to do this on 3D models that I print and was looking for advice on a good filament to print with that would absorb the liquid light. The manufacturer of the liquid recommends using a semi-gloss or glossy clear polyurethane to treat nonabsorbent surfaces, but I was hoping to avoid this. Anything would be appreciated and helpful!

If PU works to treat existing surfaces, TPU - available in a lot of different hardnesses - sounds like a good thing to try.

Have you thought about using a porous design printed on a resin printer? of course the pores would be relatively big but surface tension would likely keep the part soaked.

@FarO If it's for purely artistic purposes and original surface quality doesn't matter, one could also try reducing the flow for the external perimeters so that the outside layer before ill-extruded and porous.

PrusaSlicer (free, multi-platform) supports a feature known as fuzzy skin. Text below from linked page. Additionally, Cura slicer and Super Slicer also support this feature.

The Fuzzy skin feature lets you create a rough fiber-like texture on
the sides of your models. If enabled, the perimeter will be resampled
with a random step size and each new sample point will be shifted
inside or outside of the perimeter by a random length limited by the
Fuzzy skin thickness. This simple algorithm produces surprisingly nice
results suitable for tool handles or just to give the print surface a
new interesting look or to hide print imprecisions. You can also use
modifiers to apply fuzzy skin only to a portion of your model.

This would result in a roughened surface, if the right parameters were used, allowing surface tension to secure itself while the "outward" or fuzzy portion might prevent shearing or peeling.


text:
Configuring HD44780 LCD with I2C backpack in Marlin
I'm making a custom control board based on an ESP32, and I'm currently stuck at trying to configure a 16x2 LCD in Marlin.
In Configuration.h, there's an option for a "Generic LCM1602 LCD adapter", which I've commented out. However, after searching thru everywhere in the source that came to my mind, I've yet to find any option for specifying the I2C pins or address the LCD backpack/adapter is connected to.
Could someone point me in the right direction, or where the LCD is instantiating, so I can modify the respective lines to make it work with my LCD? Any help would be greatly appreciated!

If you do find a solution, please post the answer here, as it will probably help others with a similar issue.

I2C connection
I may have not researched enough, or maybe I've mis-read various articles, but using I2C would seem to be (much) more tricky that a straightforward non-I2C connection, and might be a project unto itself. Unless you have a lot of time on your hands - or a need to minimise the number of pins used - it might not be worth the bother, and using a regular 1602 display instead probably makes more sense.
G-code
This seems experimental, and possibly suffering from a lack of documentation.
There are two G-code commands, M260 - I2C Send and M261 - I2C Request that require EXPERIMENTAL_I2CBUS. The second link refers to an I2C master/slave article, by unfortunately, no link is provided (Ed. - if someone knows the link, then please edit it in).
configuration.h
This seems to be most promising option.
The Marlin configuration page, Configuring Marlin, shows two interesting tables for I2C displays:

This is the LiquidCrystal I2C library that is referred to above each table.
A Marlin issue on Github
This also seems hopeful.
This post on I2C in Arduino for Marlin #10399,

It's not too intensive. Many peripherals use i2c.

Marlin uses Wire on most platforms. Enable EXPERIMENTAL_I2CBUS for a simplified interface in Marlin, and check out this thread (Dual Serial Port #4776 (comment)) for insights into using i2c to talk to a second board.

Yes, you can send data over i2c anytime. See the aforementioned thread for more insights into using the EXPERIMENTAL_I2CBUS to test i2c communication.

A working example
This option might be overkill.
This blog, I2C Port Expander & LCD working with Marlin, actually has a working example of an I2C 2004 LCD. It also lists the changes required for configuration.h
However, unfortunately, it requires an additional DIY I2C port expander PCB, which employs a MCP23017, which is detailed here, I2C port expander driving an LCD screen, click encoder and more.

An example of the revised v2.1 PCB is shown in a subsequent blog, Panelolu2

This requirement of additional hardware maybe more that you had expected. However, you could just use a breadboard to make this interface board (port expander).
Non-I2C connection
According to this post on the RepRap forums, MARLIN - generic LCD 16x2 (Megatronics 2 board), the pins are defined in ../Marlin/src/pins/pins.h (the name of the file is a bit of a giveaway).

The following might be useful as it shows the lines to change... but it obviously depends upon your board and upon whether your 1602 LCD has buttons or not.
For the Megatronics 2 board the lines and pin numbers seem to be as follows (from the final post):

what it is now in Marlin:
#define SHIFT_CLK 38
#define SHIFT_LD 42
#define SHIFT_OUT 40
#define SHIFT_EN 17

#define LCD_PINS_RS 16
#define LCD_PINS_ENABLE 17
#define LCD_PINS_D4 23
#define LCD_PINS_D5 25
#define LCD_PINS_D6 27
#define LCD_PINS_D7 29
*/

what it should be:
#define SHIFT_CLK 63
#define SHIFT_LD 42
#define SHIFT_OUT 17
#define SHIFT_EN 7

#define LCD_PINS_RS 14
#define LCD_PINS_ENABLE 15
#define LCD_PINS_D4 30
#define LCD_PINS_D5 31
#define LCD_PINS_D6 32
#define LCD_PINS_D7 33

Worth noting from this post:

I think the ULTRA_LCD is not the same as a generic 16x2 lcd without buttons.

Additional reading
Another link (on the same forum) that may be useful is How Do I Configure Pinouts For A LCD.

Thanks for the answer! However, those instructions are for a standard 16x2 LCD without the I2C adapter. They don't work with the I2C adapter as a completely different library would need to be used, and the "Generic LCM1602 LCD adapter" option was the only one remotely close to what I was using.

I've updated my answer with some I2C stuff that I found, but you've probably seen them already.


text:
Old printed object deformed over time
I have an Elegoo Mars.
I have printed a figure in Resin, but after some months I found this - the figure is as if it is not completely cured. The base is open (see picture below). it wasn't open before!
It was printed a month ago, I am not precisely sure. I think I only machine cured and sunlight.
How is this possible?

How long did you cure it, and what was the layer time? You might have too short a layer time, the core possibly being all goo but not solid...

Those are cracks as a result of overstressing due internal stresses to further curing of the print over the course of time (stress cracks).
Most probably the print wasn't cured properly or slicing wasn't optimal.

The outside layer are perfect! So I think the problem can be slicing!

You should probably cure more, but curing should not be complete during print, or the layer will not stick properly.
Also, when you cure with UV light or the sun after the print is completed, you can cure only up to a certain depth, likely around a couple of millimetres.
If your object was massive and you didn't "hollow it" then some resin got trapped inside it and it didn't cure properly initially. It may slowly cure later, but by the time the object cracks due to stress, some resin may still be liquid enough to cause the issue.


text:
3D printing a part without experience in 3D design
I have a height-adjustable table, but the height cannot be adjusted as a gear in the motor has worn out cogs and it will not spin. The motor is functional so the only thing I need is to somehow get a that particular part. I have tried searching for the motor itself on eBay, and I found one, but it would cost more than the table did and I dont want to do that unless I know there is no other option.
I am inserting some images of the part and the engine

What I am searching/asking for, is some kind of database where I might find the 3D design or something like that. I have been trying to learn AutoCAD or a similar design tool, but for a beginner level this seems too complicated.

I seriously wonder if this part can be 3D printed as the original part, an injection molded nylon part, already failed.

I've seen this failure in a garage door opener gear set. It's wear rather than failure, but I agree that it's not well suited for 3D printing. Perhaps a 3D printed version to be cast or injection molded.

these nylon gears fail under load as a safety measure and might be purchaseable as spares.

The part is ill-suited for FDM plastic printing due to design
The part can certainly be printed on an FDM machine, but injection molded nylon is one of the best gear materials to begin with, and they fail in a very controlled manner that limits damage. PLA would shatter, ABS can't hold such loads, ASA is super hard to print...
The part might be usable if SLS printed
Nylon powder printing using Solid Laser Smelting might produce an appropriate replacement part, though of a slightly lesser quality than injection molded.
Check if you can find it in a catalog
Often, these are industry-standard parts. Some of the biggest catalogs for industry standard parts, that also offer 3D models are McMaster-Carr and RS Components. If you can dimension our the part you need, you might find that part on their catalogs. As the motor carries german text, I assume you're in Europe, so McMaster-Carr sadly doesn't deliver there, but their CAD catalogue is better.
Look for replacement parts or refurbishing kits
Your part has a number on its label - It's an OKIN OG 01, with a specific design variant under its serial number. Used motors with gearboxes of this type sell for 30 €, and new motors with gearbox trade for 100-120 €... And their teeth gears are available as separate parts for about 15 €. The spare part listing I found incidentally shows that the gear you look at is a stack of two gears, one of them splined on the other:


text:
How to generate a file for resin printing from layer by layer images?
I would like to print an object on an Elegoo Mars 3, object which is generated layer by layer via other means.
So as input I have a series of BMP or PNG black and white images, one for layer, and I need to somehow assemble them to obtain a CTB printable file.
The solution can either involve generating a 3D model to be loaded in Chitubox, or it can involve generating directly a CTB file.
How can do that?

You can do this with the open-source tool UVtools. I don't know if there is a built-in method but you can certainly achieve it by writing a short script.
If you don't find the option in the menu, you can ask in the forum. Tiago, the father of UVTools, is a very kind and knowledgeable person.


text:
Cura: Ensure wall thickness on curves
Is it possible to tell Cura that the wall thickness should be equal not only horizontal but also on a vertical point of view?
Example:
This is how it would look on a curve when I set wall thickness to 4:

No, the definition of wall thickness is in horizontal direction, not vertical or perpendicular. The hint info of the "Wall Thickness" option describes this.

However, if you have very curved surfaces that require more walls, but you don't want to have all these walls in the whole print is use a technique described in question Different infill in the same part. This answer describes the use of a different infill percentage, but you can also change the amount of walls; so in these curved regions, you could locally increase the amount of walls, e.g.:


text:
Missed hotend's thoat depth during install, is it too bad?
I replaced my hotend's thoat and I made a mistake I hope it's not fatal for the new install. After reassembling the hotend I left a marging of about 5mm of the throat out of the heatsink. I noticed something was off when leveling the bed and then confirmed it after seeing more underextrusion artifacts than expected on a test print. I fixed it but now I'm worried about the debris left by the pocket made when I missed the throat depth (see pic below)

The material used was PLA so that'll be most of the debris I guess. Is it that bad? I'm printing a second benchy right now which looks OK, but I'm worried about possible clogging in the future. This is an all-metal thoat, by the way

It’s probably fine.
If you have it tightened down all the way now, you’ve squished most of the plastic out. You might burn up some plastic if your block gets too hot, but you could easily do that anyway. You might also have some issues with cold pulling and cold-ish unloading, but I wouldn’t expect it.
If you’re worried, your only recourse is to remove the nozzle and clean it out, probably while hot. Q-tips work fairly well for that. Unless you’re doing something fancier than PLA though, I think you’ll be fine.


text:
Viability of Raspberry Pi 400 as Octoprint Server
This is a follow up question for What are viable substitutes for Raspberry Pi to run Octoprint or similar software for Prusa i3 MK3S+?
I was able to grab Raspberry Pi 400 for around $70, so at MSRP, and about half of the current pi 4b prices nowadays. Good deal given shortages, so I ordered it when it was available, and only now I started to think if I can really use it.
Thus, are there any special challenges to using Raspberry Pi 400 as OctoPrint server, and does it have any benefits over regular Pi 4B? Is there any ready-made manual about it I could use?

The recommended hardware for OctoPi is listed as:

Recommended hardware: Raspberry Pi 3B, 3B+, 4B or Zero 2. Expect print artifacts and long loading times with other options, especially when adding a webcam or installing third-party plugins.

Now if we compare the specification of the two Pi units:

Raspberry Pi
Processor
RAM

400
BCM2711 quad-core Cortex-A72 @ 1.8GHz
4GB LPDDR4-3200

4B
BCM2711 quad-core Cortex-A72 @ 1.5GHz
1GB, 2GB, 4GB, 8GB LPDDR4-3200

So they are very close in capabilities. The 4B has a slightly slower processor but does have the ability to have more RAM. The 400 does come with a keyboard but its feasibility would depend on your usage (probably not much for OctoPi).
Given the slight disparity in specs, the Raspberry Pi 400 should work fine for OctoPi.

So I can assume that, other than processor and RAM, these two are similar enough to work as drop-in replacements, and look the same for software? I have no experience with Raspberry, so I don't know.

Correct. There are other SBCs (single-board computers) that also work such as the Orange Pi, Banana Pi, Rock Pi, etc. they all use similar architecture so the OS should work. I don't have experience with the Raspberry either, but I have used different computers and OSes in the past.

While the server will work, there are some challenges.
Raspberry Pi 400 lacks the camera and screen connectors, specifically:

2-lane MIPI DSI display port
2-lane MIPI CSI camera port

so you can't use Pi screens and camera modules. You need to find compatible USB webcam if you want to make time lapse of your print or stream your build to oversee it. If you want to add a touch screen, you need to use HDMI+USB one, as most of the screens dedicated for Pi won't work without DSI port.
Pi 4b has:

2 × USB 3.0 ports
2 × USB 2.0 ports

Pi 400:

2 × USB 3.0
1 × USB 2.0

One of these will be, of course, occupied by the printer, so if you want to connect a touchscreen and webcam, with 4b you still have up to three usb ports free, when with 400 you are all out.
Built-in keyboard is somewhat redeeming quality, especially if you are old time console jockey and don't need a mouse or touchscreens, and 20% faster CPU is nothing to sneeze at if you want to use AI plugin to oversee your print. For end users not interested in any kind of hardware hacking, 400 being already assembled with case and cooling is a great benefit, too.
In summary: it's compatible, faster and more convenient for end users, but less hackable. It's also significantly cheaper during 2022/2023 Pi Shortage, sometimes being available at MSRP and in stock.

As for the number of USB ports, I don't think the 400 would be a deal-breaker since you could always connect a USB hub for lesser demanding devices.

@agarza sadly, keyboard is wired to USB port at the trace level, so sharing this least demanding device with mouse, touchscreen etc doesn't seem possible. And you don't want to have printer on the hub. This may not be a deal-breaker, but it is a disadvantage. Overall, it's two specialised and one generic port less, I believe notable difference worth considering before buying.