text:
Unable to upload Marlin 2.0 to Melzi 2.0 board
I need to set the HOME_POS manually since it isn't printing in the center of the bed. But whenever I try to upload it to the Melzi 2.0 board I get an out of sync error.
I am using Arduino IDE on Manjaro Linux, I was able to upload Marlin to the board on Windows 10 but I have since removed that OS.
I have the correct settings for the board: Sanguino Atmega 1280 or 1280P (16mhz)
Here is what I have tried to get me this far:

Running Arduino IDE as root (administrator) which fixed the
permission denied error
Changing the Board and the processor settings
Uploading a fresh Marlin firmware with no changes
Uploading a simple program to my Arduino UNO which worked
Changing USB Ports (USB 3.0, USB 2.0)
Changing the Baud Rate from 115200 to 57600

Here is the (verbose) error message
Arduino: 1.8.12 (Linux), Board: "Sanguino, ATmega1284 or ATmega1284P (16 MHz)"

Sketch uses 107854 bytes (82%) of program storage space. Maximum is 130048 bytes.
Global variables use 4054 bytes (24%) of dynamic memory, leaving 12330 bytes for local variables. Maximum is 16384 bytes.
/root/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/bin/avrdude -C/root/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf -v -patmega1284p -carduino -P/dev/ttyUSB0 -b115200 -D -Uflash:w:/tmp/arduino_build_963029/Marlin.ino.hex:i

avrdude: Version 6.3-20190619
         Copyright (c) 2000-2005 Brian Dean, http://www.bdmicro.com/
         Copyright (c) 2007-2014 Joerg Wunsch

         System wide configuration file is "/root/.arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17/etc/avrdude.conf"
         User configuration file is "/root/.avrduderc"
         User configuration file does not exist or is not a regular file, skipping

         Using Port                    : /dev/ttyUSB0
         Using Programmer              : arduino
         Overriding Baud Rate          : 115200
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x73
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x74
avrdude: stk500_getsync() attempt 3 of 10: not in sync: resp=0x61
avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x72
avrdude: stk500_getsync() attempt 5 of 10: not in sync: resp=0x74
avrdude: stk500_getsync() attempt 6 of 10: not in sync: resp=0x0a
avrdude: stk500_getsync() attempt 7 of 10: not in sync: resp=0x65
avrdude: stk500_getsync() attempt 8 of 10: not in sync: resp=0x63
avrdude: stk500_getsync() attempt 9 of 10: not in sync: resp=0x68
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x6f

avrdude done.  Thank you.

An error occurred while uploading the sketch

have you tried installing via ISP pins?

So it was already running Marlin (uploaded from Win10)? You could have used M206 to change the offsets instead of uploading a completely new firmware. On topic, this is a very common and generic error message, a troubleshooting answer can be found here.

Your board might be using the old bootloader which needs a 57600 baud rate for uploading instead of the default 115200. You'd need to modify that in the respective boards.txt

@towe I tried that it did not work ( I added it to the question now to help narrow it down)

That's odd. Enable "Show verbose output during: ... upload" in your IDEs settings please. That should give you the avrdude line the IDE uses to try to upload to the board.

I found a suggestion on the Arduino stackexchange that you remove any shields or anything connecting digital pins 0 and 1. The error you're getting is a connection error and could mean any of a thousand things. Can you do as @towe suggested and enable verbose output?

@towe there you go :)

@towe i needed to change it in the serial monitor as well thanks!

Okay thanks to @towe for helping me I figured it out.  my Baud Rate was set to 115200 but my board is using the old bootloader so it needed to be 57600.  I Changed my boards.txt file to that but the verbose console printed:
Overriding Baud Rate          : 115200 turns out you need to change it in the serial monitor as well (the little magnifying glass in the top corner of the IDE)
after that everything worked great thanks for all the help!


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Ringing with Ultimakers, what is the cause?
At my work, we have 3x Ultimaker 2+, 1x Ultimaker 3 and 1x PRUSA i3 mk3s. The Ultimakers have been used quite a lot for the past three years, but the belts and bearings seem ok.
I got heavy ringing with all Ultimakers, but the print on the PRUSA is neat even at a higher speed.
I have a Ultimaker 2+ which I use together with CURA. I print in PLA at 210°C. The print bed is set to 60 °C. I use a print cooling fan at 60 %. The layer height I set to 0.2 mm, the line width 0.8 from the 0.4 mm nozzle. The Printing Speed is set to 30 mm/s for walls and 50 mm/s for infill.
Is this a known issue with Ultimakers?
How can I fix it?

The comparison with what I get with the PRUSA is uncanny:

EDIT
I have tighten the screws on the extruding head and cleaned the machine, but I still notice a mechanical play. Therefore, the result is not satisfying...

.

I don't see any heavy ringing, or do you mean the bulging on the railing of the boat?

@0scar I've added a picture of what quality I am expecting. If it's not ringing I don't know how you call this default where the surface is rippled.

Is this old filament? My Ultimaker prints like the bottom. What material, what settings, see e.g. "Help us help you!">

The filament is not that old. I am sure it is caused by some vibrations somewhere.

Possibly a dumb question but the ringing is occurring on all 3 Ultimakers, correct? Possibly this has to do with a slicer setting that the Prusa can handle better then the Ultimaker printers (or an update to your slicing software).

@Dr.MantisTobbogan I don’t think it is the slicer’s fault. These machines are old and perhaps some components are causing this behavior

Okay, your call, just odd that all three machines developed a similar problem. I'm not sure how your Ultimakers are constructed but perhaps there are some rubber dampers that have dried out and aren't functioning optimally. Just throwing ideas out there really though...

@Dr.MantisTobbogan Actually that speaks of similar use: if 10 cars show the same behavior after the same distance, it might be the wear of the same part or a flaw in the design.

@Dr.MantisTobbogan You do need to do some maintenance occasionally by lubing the steel rods, lube is supplied with the Ultimaker. An Ultimaker 3E at work had a worn bearing bushing, I think they haven't properly lubed the rods.

Usually people post the most relevant settings as in the link posted before. But, indeed, that is not the quality of an Ultimaker. If this is PLA?, 215 °C is quite high. What is the printing speed, jerk, accel...

have been used quite a lot for the past three years

The problem, even if belts and such seem ok, might be that other parts start to wear out. The part that contributes te most to ringing is the motion system. Grooves in rails or worn out bearings are a classic way that introduces some freedom in the system that can result in rattle and ringing. A photo of the rails and bearings might help to identify wear. Remember that most bearings need some sort of lubricant to work properly and reduce the wear in them, which should be part of the maintenance cycle!
Another source for the errors could be found in the extrusion system. For example, there might be an increased play in the gearing as springs under constant pressure can lose some tension, resulting in too little pressure on the filament, which typically would show up as under extrusion if the pressure is lost completely. On the other side, the hobbled gear that pushes the filament might be worn, resulting in a lack of responsiveness of the filament movement, again resulting in under extrusion after some point. Once more, photos of this area could help to indicate wear and tear.
Another source might be the mounting of the printer - it has been shown beneficial to put printers on a slab of concrete that itself is dampened on a medium density foam, resulting in even dampening that is usually better than the rubber feet of many printers.

Very likely due to the extrusion subsystem. Ultimaker uses 2.85 mm filament so filament motion is critical: a little slippage causes visible changes in the extrusion. If the teeth are worn out, this is the case. Worn out bearings (or dirty bearings) can also cause the same, since motion is not smooth.

I've added a photo to my question if it can help.

@nowox That are worn bushings/rods as far as I can tell.It doesn't show the inside of the extruder so hard to tell if there might be other worn parts.

source: Stack Exchange

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

sort: votes


text:
Increase Z-homing probe number
I'm using latest stable Marlin 1.1.9.1 with BLTouch. The BLTouch seems a bit damaged so I want to increase its accuracy with multiple measurements.
I've increased #define MULTIPLE_PROBING to 3 but it seems it applies only to mesh ABL and doesn't work with single center homing.
I want to get something like fastprobe + average for two or three slow probes.
Am I missing something? Or it is not possible?

Homing and mesh probing are 2 separate actions, by setting #define MULTIPLE_PROBING to 3, you inherently create 3 slow probing points for the mesh probing (not the homing probing), with 2 you get a fast/slow probing action.
Everything is possible, but, that means that you need to dig into the sources; not changing the configuration constants. That is not for the faint hearted.
I've seen the responses of fast and slow probing in action, usually the difference is not existent or very very small, like one or two hundredths of a millimeter, I seriously wonder if it makes sense to use more than 2 probing points.
Please note that a damaged bed may benefit more from increasing the probing array amount (from 3 x 3 to 4 x 4 / 5 x 5). The number of probing points discussed earlier only dictates the amount of probing actions in a single point; if the sensor hits the bed the probe measurement is done, if it hits again, the value should more or less be the same (give or take the accuracy of the sensor), I do not see what damage to a bed would imply more probing measurements in a single spot. The only rationale would be if the sensor itself has a large inaccuracy with an error that is not systematic, but random. My BLTouch (original) is pretty accurate and repeatable, I've had more issues with all those cheap knock-offs.

Ofcourse everything (almost) is possible :)
I mean POSSIBLE to change by some with some define constant. And you confirmed my assumptions that NO.
Originally was talking about damaged probe, not bed (It was edited by moderator)

@Dmitriy My apologies, it was not clear, the bed was assumed as it was not referenced what it was. I have reverted it. No harm intended. Please add what damage the probe has.

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


text:
Eliminating unwanted internal surfaces
One of the biggest challenges with 3D-drawings is internal surfaces unintentionally formed that cause slicing not to work properly. This is using SketchUp Pro, slicing with Slic3r, and printing with a Reprap X400. Eliminating lines unnecessary to form the outside surfaces helps, but this may not eliminate all the internal surfaces which can be hard to see even with an x-ray view. It often takes deleting an external surface, looking for internal surfaces to select and delete, then adding the external surface back, being careful not to use a line that also adds the internal surface back.
This can be a huge issue when importing an STL file into SketchUP. The import seems to prefer using all triangles and thus the maximum number of lines with no attempt to see which are unnecessary, leaving it up to the user to eliminate lines.
What techniques do you have for eliminating or avoiding unwanted internal surfaces in drawings?

I am sorry to tell you that SketchUp is not a good software for printable 3D designs due to its exporting feature not properly reducing complexity. It creates unnecessary faces and vertices inside of items on a regular basis, which in the slicer creates artifacts.
To make a SketchUp created file well printable, a huge amount of careful re-engineering in a graphics program like Blender is needed, manually removing the excess vertices surfaces.


text:
Patchy first layer on glass bed
The part at the front has only one layer, and has what appears to be uneven patches. The part at the back has had two layers, so it clears itself up.
The build plate is flat, and level (I levelled it before the print) and by the way the patches are all together I think I can rule out flow issues.
What is going on, and is it a problem? See the image below, for an example:

Setup and configuration:

Sheet glass bed
White PLA (Geeetech from Amazon) - opened the same day
190 °C nozzle, 55 °C bed
Ender 5 printer, with Cura 4.6 slicer

I have changed the filament (still PLA), re-levelled the bed, and here is the bottom of a large flat surface:

Also the top surface has 'ringing' artefacts (I think that is what they are called?):

Maybe the nozzle is a little too close to the bed. Maybe it begins filling a "patch" (or area) well, but because of being too close or a little over-extrusion the pressure builds up and generally deposits more filament, if it then moves to the next "patch", the pressure relaxes, and starts correct again. Cura has a marketplace with plugins, you could try increasing the nozzle to bed gap with the plug-in from "fieldofview" called "Z offset".

@0scar that's a great idea! I am going to try levelling again, and maybe changing the nozzle. It's a bit old I have lots of spares.

@0scar, just updated after some more prints. What do you think?

It is difficult to see, but I think it is still a little too close judging the bottom image. But I noticed the bottom layer image, that suggests that the nozzle isn't too far from the bed...

That was brushing a bit of 90gsm paper

It is pretty difficult to see, I would download the "Z offset" plugin from FieldOfView from the Cura marketplace and experiment. You can also play with redefinition of the Z=0 in your start G-code; move with G1 Z0.1 and then G92 Z0.


text:
How does wireless 3D printing work?
I was wondering how WiFi based 3D Printing works since I want to start an open source project and need some information on this. I have done some research, I have now an understanding on how the printer interprets the G-code and how it acts upon the instructions. But what I couldn't find information on is how WiFi based 3D printing works

What is the communication between the slicer (such as Cura) and the board?

How are the commands sent to the printer from the slicer, line by line or the entire G-code?

How do I establish a connection between the slicer and the board?

I am well aware of the already existent Raspberry Pi idea compatible with Octoprint but I am making a much cheaper one
Thanks for any help

Slicers don't talk to the printer. Slicers analyze an STL file and generate a GCODE file, based on your parameters. A print manager sends the commands from the GCODE file to the printer board, which executes them sequentially.

They are not. Commands are sent to the printer from a print manager of some sort. This varies among printers; some printers can be managed by more than one manager, and some managers can handle many models of printer. Some printer-manager pairs are proprietary and exclusive.

You do not. See above.

Note, some programs do have an integrated slicer and print manager. - Thanks, Trish

" A print manager sends the commands from the GCODE file to the printer board, which executes them sequentially." - does this mean that the printer receives an entire G-code file and then executes them, or the print manager send 1 line of commands

It depends on how much (if any) buffer or storage the controller board has. It can be a small number of lines at a time, or it's possible the entire file can be queued up on the controller. The units I use have a 300 line command buffer, plus an emergency buffer.

You shouldn't send G-code over WiFi, this is potentially more risky than a stable wire connection.

@0scar: Do you just mean you shouldn't stream it because of risk of the printer being left in a bad state (e.g. hot nozzle sitting on the print) if the signal drops out? Or something else?

Some slicers do contain a printer manager, but generally, they do not.


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Use SLA 3D printing to make a flexible mold
I have seen some videos like this one, that uses 3D printing to make a piece that will be used to make a silicone mold that will then be used to make the final object made of some resin.
Isn't possible to make the mold directly from the 3D printing process?
I want to make an object (that's actually another mold to make tofu) using a flexible mold. Can I use 3D SLA printing with a flexible material such as this one and then use it to make my final mold made of some liquid resin? Also, do you have any suggestions about food grand liquid resin or similar?

Background
SLA relies on the properties of UV-curing Resin. Most currently available UV Curing Resins harden to a solid, hard polymer, but that doesn't mean there are no other UV curing resins that are elastic. Most however will not be suitable for SLA or DLP systems!
Polyurethanes, which can be flexible if cured in the right way, have not come onto the market as suitable SLA/DLP printing material and up to now, I have only found one UV hardening resin on the market - the one offered by FormLabs and identified by OP
Patent History
Indeed, elastic resins are actually quite new. The first patent I could find for an elastic resin was 2003 for an elastic epoxy resin, while subsequent elastic resins were brought to Patent are different like the 2007 elastic olefin resin. In fact, there is a 2013 US patent on SLA Resin, which is still in effect. As a result of such patents being still in effect or just out of protection times, the market is still very much limited because most manufacturers simply lack the knowledge of how to do it or the licenses to be allowed to do it. In fact, Formlabs is named on 43 patents for 3D printers and accessories, of which only 1 is expired as of July 2020. I could not identify the patent that might be in use for their flexible resin, but the marketing material is of May 2020, so it is relatively new on the market and might not have been updated into either the patent database or FormLabs did buy an exclusive license for the material from someone else, meaning they will not show up as Assignee in it. Or it is kept a trade secret.
Material implications
The printed mold will probably be of a different stiffness than a cast mold as you work with a totally different material and your new molds might degrade at a different speed than urethane or latex cast molds. To get a feel for this this, you will need to run some experiments. As FormLabs hands out test specimens of their print materials, you might order the two flexible ones and then test their stiffness and suitability for your uses by having them interact with your casting resin and seeing if they break down and if you can remove them easily.
Food grade
Generally don't consider anything that comes directly from a 3D printer certifiable food safe, as you need to have both a process and a material that is food rated. There are ways to use the resulting parts to manufacture food safe objects, but that's elaborated for example in some of the questions I suggest to look into

Ok, thank you very much for the detailed explanation!

authors: ดีไม่ดี อยู่ที่ฟังใครมา


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How to measure the nozzle diameter?
On a Creality CR-10 Max, there is a bag of unidentified spares, which include three unmarked nozzles.
There is a needle that is exactly 0.4 mm in diameter, which needle fits exactly inside one of nozzles. It also fits loosely in the largest nozzle, which diameter looks like it's really close to 0.8 mm on my digital caliper. The smallest one has only room for the tip of the needle, and the digital caliper reads 0.34 mm on the tip of the needle when pushed from the inside of the nozzle.
I assume the sizes are: 0.8 mm, 0.4 mm and 0.3 mm.
Can you tell me how to measure the diameter with better accuracy?

You don't really need to measure the diameter with any degree of accuracy since it is irrelevant for printing. The diameter of the extruded plastic is controlled by changing the flow rate of the extruder v.s. the movement speed of the print head. The exact nozzle diameter does not factor into it in any way. It only loosely determines what extrusion diameters are feasible (e.g. you can't extrude a 1mm line with a 0.2mm nozzle and you can't extrude a .4mm line with a 1.2mm nozzle).

Tiny addition on Tom's: it's generally irrelevant, but the nozzle diameter is used to set up the basic extrusion width in general. Sure, you could try to force 1.2 mm extrusion through a 0.2 mm nozzle but possibly get extreme under extrusion and clogging. Try to get them fitting.

Interesting.  I will read on the subject and come back later. How important is it to match the nozzle size in the slicer with the installed nozzle ? Can you give me an example of a problematic mismatch ?

@alecail It does not matter for the slicer. The nozzle diameter is not used when slicing at all. Slicers only ask for the nozzle diameter so they can suggest values for the other settings (e.g. for extrusion width). If you get it right within +- 0.1 there should be no problems.

I have found that normal measuring devices are not particularly helpful with accurately measuring nozzle diameters. But you're already off to a great start.
What is helpful is to take them somewhere that has a wide assortment of drill bits, and find which two adjacent sizes will and will not fit in the (clean) nozzle; then convert the diameters to mm (if needed), and your nozzle is larger than the small bit, but smaller than the large bit. From that, you should be able to narrow it down to a standard dimension.

How about the physical size of the nozzle verses layer height?  Does it work to tell a 0.2 nozzle it is 0.4 mm and have a 0.3 mm layer height?

This is another question. Please use the Ask a Question link and we'll help you. :)

The correct tool for measuring a hole usually is a Bore Gauge, but that doesn't work for super small holes like nozzles and generally needs holes at least 5 mm in diameter. For those small holes, there's a different tool:

These are Thread Measuring Wires of known diameter. While generally used to find out the depth of thread you are dealing with in a threaded (or if your thread is correct depth), they are also useful for measuring small bores. In this capacity, You'll use them as follows: The diameter of a hole can accompany any smaller diameter, but never a larger diameter wire, so a clean nozzle of 0.4 mm should accompany a 0.3 and o.35 easy but not a 0.45. A 0.4 might or might not fit, depending on how accurate the hole is. You'll need a very fine set of thread gauges though, and wires, pins, and needles of known diameter are a suitable replacement for this.

authors: Тимофей Вуколов


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Thermal runaway when power on
I get the error "Thermal runaway on E1. Reset printer." today on my Tevo Tarantula when powering on the printer. The display shows the error and the speaker beeps loudly everytime I power on the printer or reset it.
I use the firmware
https://github.com/JimBrown/MarlinTarantula, because I can switch E0 heat nozzle to E1 wires, without soldering; PID's for nozzle were configured, and works fine before I replaced the power supply.
Recently my power supply was broken, and today I installed new power supply, clean nozzle, several times start bed leveling, and on fourth time of homing error appeared.
Power supply voltage tested with a multimeter and the voltage of power supply is 12.06V.
Note: several times printer started bed leveling.

Do note that Marlin internal naming for extruders starts with 0 (zero), but, error reporting and menu use naming starting 1 (one).  Thermal runaway should only be triggered when heating the hotend. Strange that this happens when you turn on the printer or after levelling.

Agree, it is strange. I will test ceramic heater tomorrow. I think that short circute is at ceramic heater either at hotend or board connection. I will replace it if so. I will comment result of tests.

Issue is solved. Root cause was at broken thermistor circute at board and broken thermistor. I disconnect all wires and power, measure board nest thermistors  resistance: E0 = ~120 Oms, (E1 and Bed) = ~700 Oms. I changed pins at Marlin for Tevo pins_RAMPS.h as at https://3dprinting.stackexchange.com/questions/10208/change-hotend-thermistor-input-in-marlin, changed thermistor at everything prints fine.

When I last updated my Ender 3 pro I also downloaded a boot loader which set certain parameters.

Issue is solved!
Root cause was a broken thermistor circuit at board and broken thermistor.
I disconnected all wires and power, measured board and thermistors resistance: E0 = ~120 Ω, (E1 and Bed) = ~700 Ω. I swapped pins for TEMP_0_PIN and TEMP_1_PIN within Marlin for Tevo firmware at pins_RAMPS.h as described in answer on question Change hotend thermistor input in Marlin, changed thermistor and everything prints fine.

authors: Дмитрий Курков

authors: Останин Вадим

authors: نايف بن تركي


text:
How do slicers convert an STL file to G-Code?
I was wondering how slicers work, how their code runs to generate a G-Code file. How is an STL file interpreted through a slicer.
How does the math work for generating supports, build plate adhesion?
I couldn't find any information, so can anyone help with this technical question
Ryan

This doesn't seem to have anything to do with the firmware (marlin) or a specific slicer (Ultimker Cura) but with slicing in general.

Slicing in General
An STL is a set of triangle surfaces. A Watertight STL - for slicing purposes - has surfaces that always create closed outlines if cut parallel to the XY plane.
A Slicer does exactly that: it creates plane-cuts at the indicated Z-heights, takes the plane-cut's outline(s), and decides a direction and order in which to follow the generated path. Then it uses this outline to generate the infill pattern, for example, as explained here.
The more paths there are and the smaller the triangles that are cut up, the more complex the solution process becomes and the longer it takes.
Support calculation
A slicer usually identifies areas that need support by calculating at which angle an STL Surface cuts a given plane cut. Under standard settings, this would be about less than 60° to the XY-plane with the normal of the surface having a negative Z-component - which means that a needle poking out of that surface points towards the bed.
The most simple form of support generation simply generates a grid pattern between such areas and the bed or next surface below. Tree support on the other tries to generate a support structure that bends around the object without intersecting and only relying on the support of itself.
Build Plate adhesion
A skirt and brim are just taking the outline of the build-plate intersection and surround that with outlines.
A Raft is generated like the simple support case, but taking the whole base of the object, adding a little edge around it and then generating the support grid there.


text:
Printer scaling is randomly off
I built a custom 3D printer using a BTT SKR Mini e3 v1.2 and use Pronterface to run my prints.
The problem I've been experiencing with it is from time to time the printer will attempt to print with a scale much bigger than what I wanted (roughly twice as big). I test with the same slicer file, and on different attempts it will print with different scales. It seems that the stepper motors run twice as fast and that is what is causing the change in scale. Has anyone had this happened?

Is it 2.54 times larger, as if something was using centimetres instead of inches?

Could be number of microsteps being programmed inconsistently...?

How could I check if the microsteps are programmed inconsistanty? Isn't there one place for it? I suspect the problem is in the slicer or pronterface.


text:
Ultimaker Cura is not always retracting in exported G-Code
TL;DR: Upper layers of a stringing pyramid test are missing retractions in the G-code.
Edit 1: added printer info and additional settings.
Edit 2: Clearing up confusing wording.
Update:
I wrote a program to parse the G-code and count the retraction-extension pairs between layers. The first 17 layers (base) and 18-95 (pyramid start) have the appropriate number of extruder calls. I expect an extension at the start of the layer, retraction before moving to the second tower, extension to print the second tower, and a retraction before moving back to the first tower.
After layer 95 of 391 the number of retraction pairs starts to decrease from missing a pair every other layer to eventually almost no retraction pairs. The last 70-ish layers have a retraction pair every dozen or so layers.
Perhaps this is related somehow to the shrinking width of the pyramid since the missing retraction-extension pairs increase as the pyramid comes to a point
Disabling Z-Hop shows no difference in this behavior
Original question:
After switching to a 0.2 mm nozzle I starting printing some calibration tests to find my stringing pyramids end up looking like a pair of trees. I suspect I've always had this issue, but it's much more evident now with a smaller nozzle that likes to ooze.
This is on an Ender 3, so using a Bowden tube, with a MicroSwiss all metal hot end and the extruder mechanism is aluminum with a pair of toothed drive gears. I'm seeing the problem in 1.75mm PLA of multiple well regarded manufacturers.
Relevant Settings (let me know of other settings I should list):

enabled retraction
combing mode 'off'
enabled z-hop when retracted
retraction distance 3.5mm
retraction speed 50mm
retraction minimum travel 1.5mm
Infil 100%

Looking at the G-code, sometimes I see a retraction paired with the Z-hop, but sometimes it's missing. It seems pretty random for when it's missing, but the first quarter or so of the layers do not show the problem. Originally I thought it had something to do with extruder drift over time, or something crazy, until I looked at the G-code and saw it was missing commands.
Snippit of retracting for Z-hop:
G1 F1200 X204.632 Y161.781 E77.9224
G1 F3000 E74.4224
G1 F300 Z7.08
;MESH:NONMESH
G0 F9000 X190.179 Y161.901 Z7.08
;TIME_ELAPSED:2354.891407
;LAYER:171
;MESH:string_test_fast_pyramid.stl
G0 X190.179 Y161.901 Z7.12
;TYPE:WALL-INNER
G1 F300 Z6.92
G1 F3000 E77.9224
G1 F600 X190.179 Y161.555 E77.92356

Snippit of not retracting for z-hop:
G1 F1200 X204.473 Y161.666 E78.0239
G1 F300 Z7.12
;MESH:NONMESH
G0 F9000 X190.182 Y161.898 Z7.12
;TIME_ELAPSED:2359.620803
;LAYER:172
;MESH:string_test_fast_pyramid.stl
G0 X190.182 Y161.898 Z7.16
;TYPE:WALL-INNER
G1 F300 Z6.96
G1 F600 X190.182 Y161.558 E78.02503

Test on the left is done with 'Equalize filament rate' enabled, on the right side is  done with the option disabled.

Any advice you can give as to what settings I am missing or misconfigured would be much appreciated.

Are you entirely sure the stringing corresponds to where retractions were skipped? In other words, do the initial layers that look ok all have the correct retraction? I'm not sure what would be making Cura mess this up, but I your settings (Z-hop and low retraction distance) look suspect for causing this kind of stringing themselves.

The only plausible explanations I see for the missing retractions are either a higher "retraction minimum travel" setting than you reported (you say "I think" which is not reassuring) or a bug in Cura. I certainly wouldn't rule out the latter. It might be an interaction with Z-hop, so it would be worth turning off Z-hop to see if that makes it go away. I'm not sure why you're using Z-hop to begin with; it generally causes stringing rather than fixing it, and only makes sense if you have warping issues that are making the nozzle collide with part and knock it off the buildplate.

I'm sorry for the confusion. The 'I think' was to say I am not sure which settings are relevant. The values for the listed settings are accurate. I have edited to clarify this. I was under the mistaken impression that z-hop helps force the retraction. I will print another test without z-hop and post the results.

It's likely that you're hitting Cura's Maximum Retraction Count (retraction_count_max) within the Minimum Extrusion Distance Window (retraction_extrusion_window). This is a misfeature supposedly designed to avoid grinding/flattening the filament, but of course acting on it will ruin your print in exactly the same way you're seeing. I think setting the window to 0 or the maximum count to some ridiculously high number like 1000000 will fix the problem.
Note that it's exacerbated by the thin nozzle making the number of retractions needed take place over a much smaller extruder-axis move distance than what you'd have with a normal 0.4 mm nozzle. This is probably why nobody has noticed and complained about the badness of Cura's defaults here.

Thank you!
After increasing the Maximum Retraction Count, the G-code shows all the expected retractions. It makes sense that the allowed retractions would be used up at an increasing rate as the pyramid grows. A 0.3mm Minimum Extrusion Distance Window would be required to have all retractions within the default 100 maximum due to how little material is extruded for the final layers.
Regardless, I can understand the developer intent behind these settings since its only a loss in print quality to ignore the retraction as compared to a potential failure to extrude which ruins the print.

@Spottenger: Skipped retraction is also a failed print. Every string is material that was supposed to be somewhere else and didn't get there, meaning you have underextrusion and thus insufficient bonding that will cause the part to break or otherwise not function properly (assuming it's functional and not just decorative). So this really is a bad default - it's trying to reduce chance of one type of failure by creating a guaranteed failure of a different sort.


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Ready to use objects instead of 3D-printing them
I hope this kind of questions are tolerated here. Otherwise, please tell me in the comment and I will delete the question - no needs to downvote.

For a new job I need to create a lot of objects like this one:

To have an idea of the dimensions:

height: 60 mm
cylinder diameter: 12 mm
inner hole: 3 mm
lateral slots width (2 at 90 degress): 3 mm

I'm able to make such an item with either a 3D printer or even a standard 4-axis CNC.
But because I need to make 100+ of these items I wonder if there are something similar out there.
But I have no idea of how it might be called. I tried with "spacer with slots" without any useful results.

If your printer is reliable enough I would suggest printing multiple parts in one go. Since the cylinders are only 12 mm in diameter you can easily fit over a hundred of them on a standard 20 x 20 cm built plate with a couple of millimeters spacing in between.

You could fit that many. My experience is it makes individual layer times too long, creating problems with warping, especially in the early layers. I'd go for lots of 20 or so.


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Replacement teflon (PTFE) liner For Dremel 3D45
I had filament on my 3D45 coming out of threads on the nozzle.
To fix this I removed the nozzle to find the PTFE Liner in really bad shape. It looked crushed and deformed. Now the tough part, how do I replace the PTFE Liner. You can't seem to buy the liner and getting a replacement nozzle assembly from Dremel takes weeks. Can anybody help me figure this out please, I really would like to get back to printing!!

Have you compared the existing nozzle to the generally standard nozzles one can find on the market? If you discover, for example, that the nozzle matches the specs for an E3Dv6, there are many options. Have you measured the outer diameter of the PTFE tubing? There are two "standard" sizes, one for 3 mm filament and one for 1.75 mm filament.

I think this might be it,Outside Diameter: 3mm; Inside Diameter: 2mm. Now the length. I have nothing to compare it to.

The initial problem you had with filament coming out of the threads at the nozzle is caused by improper seating of the heat break to the nozzle. In a "from the ground up" installation, you'd have an empty heat block, containing your heater core and your thermistor. Threaded into the "bottom" of the block is the nozzle, just a turn shy of being flush with the heat block. The heat break is the thin threaded segment extending from the heavily finned heat sink.
The heat sink/heat break combination is threaded into the heat block until it contacts the nozzle, at which time, the nozzle is snugged into place securely. This keeps continuous the filament path from the heat break to the nozzle. Somewhere in time, a gap opened between the two.
When you have assembled everything (including the PTFE liner), you'll want to heat the extruder assembly to about 250 °C and re-snug the nozzle to the heat block and heat break. Hold securely the heater block, as you do not want to apply force that will snap or otherwise damage the fragile heat break. Use a wrench that fits the heater block without contacting the wiring. Use a wrench that will keep your fingers safe, as the heat block will be hot.
Stepping back in time a bit, when you remove the assembly, you should be able to determine the necessary length for the PTFE tube. I checked the manual for your printer and it is lacking in detail for this information. The diameters you've specified are standard and you should be able to locate a suitable substitute from many online sources. Amazon, Matterhackers, eBay, etc.
Examine the heat break tubing. The diameter should not be so small as to allow you to push the PTFE tubing in from the heater block side, unless you have an unusually manufactured product. Dremel may have decided to create a new bit of engineering, but I'd expect not.
You'll purchase more PTFE than required and examination of the upper portion of the heat sink should give you a clue how much to use. When the cover of the extruder assembly is removed, is there a guide for the filament to make it easier to push through the PTFE tubing? If so, the length of the PTFE is from the bottom of the guide to the bottom of the bore of the heat sink/heat break assembly.
Photos of the upper entry to the heat sink/heat break, with the cover removed, would be useful, but you may have sufficient resources in hand to resolve your problem, once you replace the nozzle and purchase PTFE tubing of the correct size.

Capricorn sells 3x2mm ptfe heat break tube. Havnt used it long enough to know if it will hold up to its claims of withstanding temps up to 275c and beyond for any length of time; but I do know the generic ptfe I had in it before lived up to its reputation of going funny at 240c even though they sell it as rated for 250c. But capricorn has a good reputation in general it seems; and I can already testify that the reduction in friction in my bowden tube certainly did live up to the hype, so id recommend giving them a try.


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BLTouch doing poor job of levelling
I'd appreciate any advice on this problem. I have and Ender 3 Pro with a glass bed. I have been using Marlin 2 with mesh bed levelling and it has been working really well. I have now installed a BLTouch version 3.1. I have used the TH3D Marlin V2.0.5.3 set to probe a 3 by 3 grid (same size I used with mesh bed levelling. My glass bed has a dip in the centre. When using mesh bed levelling this was found to be around 0.05 mm lower than the rest of the bed. However, the mesh bed levelling worked well and I got great first layers. Now with the BLTouch, I've set up my probe Z-offset, done with the bed and nozzle at full printing temperature. I've got a test print of 9 small squares and have sliced it in Cura at 0.12 mm. It's just one layer. No matter how much I fiddle/tune the Z-probe offset, I am getting poor results. The square at the front left of the bed is a complete load of spaghetti. The others are better but not perfect. It's as if the bed levelling process is not working properly. But it all looks like it's doing the right thing. Is there any way I can verify the measurements the probe has made? Is there anything else I should check? I'm really at a loss. I've also manually levelled the bed to make sure the four corners are level with each other. I'm completely stumped!

Found the cause of the gaps. it was one or both of the following:: he x-carraige belt was rather loose; I think I'd overtightened the x-carriage assembly with the print head on it and the motion had a couple of places where it was a tad tight. Adjusted both these things and all the problems went away. What's especially interesting is that I'm now getting better quality prints than I've ever had. It looks like it is worth checking the tightness of everything on a new Ender 3 Pro to ensure it is all as it should be!


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Why is BLTouch Still Probing Off the Bed Even When `NOZZLE_TO_PROBE_OFFSET` is Set?
So I am almost finished upgrading my CR10s with Hemera and BLTouch hardware, however I can't get past this one problem.
In the picture, you can see that the probe is to the left of the nozzle, and when homed it is not above the bed. The gantry will fall and eventually have the nozzle crash into the bed because the BLTouch will never hit the bed. I tried solving this by setting NOZZLE_TO_PROBE_OFFSET { -40, 0, 0 } (I'm using Marlin 2.0, and those were the offsets I measured (except for the z)). This changed nothing, and the same thing happened again. I could not find a setting that tells Marlin where the nozzle is after it has been homed. Any ideas?

Did you load the values from firmware after the re-flash? Use M502 to load the values you changed, otherwise it will keep using those from memory. Also set #define Z_SAFE_HOMING, then it will home in the middle of the bed.
Also, with a new carriage for the Hemera, your nozzle is not/might not be in exactly the same position as before as I learned from other adopters, you then should also need to redefine the offsets, see How to center my prints on the build platform? (Re-calibrate homing offset).


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Filament consistently jamming / clogging in Bowden tube on MP mini 3
I've had this MP Select Mini III for years and years. Lately it's consistently jamming/clogging somewhere between the hot end and the PTFE tubing - but not right away, often when it starts getting to the infill layers.
If I don't catch it in time, the filament twists and twists until even the Bowden tube is clogged (and then it's a whole lot of trouble to clean out).
My temperature has been wobbly of late, so I bumped the temps higher than usual (200-210 °C for PLA) thinking perhaps it was dipping low for a spell and allowing it to cool.
Is this the end of the road for this cheap little guy that has been a solid workhorse or are there some known fixes that I should consider?

If you had it for years, have you ever replaced the Bowden tubes and hotend liner? Might need some maintenance. Is the tube securely fixed? If infill starts, it might be retraction that is giving problems.

I agree with @0scar, check and make sure the tube is securely attached, a loose fitting can cause issues like this.

If you have it for years, have you ever replaced the Bowden tubes and hotend liner? This printer might be in need of some dire maintenance.
Also check if the Bowden tube is securely fixed, if infill starts, it might be retraction that is giving problems by lifting the tube alongside the rectracted filament.


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Print quality ruined after firmware update i3 mk3
I'll try to give as much detail as I know here but let me know if there is anything missing.
I have a Prusa i3 MK3 that I got in about 2018 and it was working perfectly fine. Print quality was pretty good. Then sometime in the last 6 months I updated slicer and the printer would give me an error about the file being for a different printer type. I ignored it because I was pretty sure I had it set right and the prints were still coming out fine. Then recently I updated to the latest firmware version (3.9.0) from the website for MK3. When I did the update it told me this was firmware for a different printer type but I ignored it because I had checked again that it was the right version. Now when I print I do not get a message about the printer being the wrong type but the prints fail every single time.
Here are some examples:

I have tried messing with the settings a bit but they used to work perfect on default. What should I do here? Revert to an older firmware version?

Firmware controls Z offset and steps per mm which impact on print quality, your prints looks like they are over extruding. As if you have the incorrect firmware for the hardware you have. You could revert to find out.


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Marlin won't start up on modified CR10s
I have been adding a Hemera and BLTouch to my CR10s, and finally finished everything, flashed the firmware, and everything worked fine. However, I forgot about one thing (Probe_to_Nozzle_Offset), so I went back in made the changes, compiled it and that completed successfully. I uploaded it via Cura, and it gave me the upload finished message, so I closed Cura and went back to working. However, when I turned the printer off and back on, it wouldn't boot up. It would only show the Marlin screen, see e.g. this video.
It stays like that for as long as I have looked at it.
Now I am also having troubles uploading new firmware. Cura will not detect the printer is connected, Arduino will not either, and Platformio gives me some timeout error, which I looked up and it means that the uploader couldn't connect to the bootloader. I don't know any other way to upload the new firmware, and for now my project is stuck because of it. I have 2 ideas of what happened:

The upload was not completed and was therefore corrupted when I closed Cura.
The build was broken, but because it compiled fine I don't know how this could be.

Does anyone know what could have happened, or how to fix it?
EDIT:
VS code/platform.io recognized the usb port, and tried sending over the firmware.hexfile, but all I got was this warning over and over:
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_getsync(): timeout communicating with programmer

And then later:
avrdude: stk500v2_command(): failed miserably to execute command 0x10
avrdude: initialization failed, rc=-1
         Double check connections and try again, or use -F to override
         this check.

Everything was plugged in, and the lights on the board were being powered by the computer, so there was still a connection, but for some reason this warning happened, and then went right back to the avrdude: stk500v2_ReceiveMessage(): timeout
Also, I looked in the device manager when my USB to ISP was connected, and it wouldn't show, which explains why Arduino IDE won't upload the bootloader, but in that case is my only option to buy an Ardunio?

Have you seen this?

I have an USB to ISP, but arduino IDE kept saying “error while burning bootloader”

What most likely happened is that the firmware got corrupted during the transfer. Do you have a way of reverting to the old firmware without dismantling the machine? Don't worry this sort of stuff happens a lot.

I have a working version of marlin on my computer, but can't upload it

The same thing just happened to me.
Did you find a solution?

if you have an ISP connector, you could re-flash the bootloader... then install fresh

In my case, I happened to remember that I had a old version of marlin on the SD card that came with the printer (I think all of them do), inserting that SD card fixed it (that reinstalls marlin), but if you get a clean card and download marlin to it it should work. I could then install the firmware again, and it worked fine


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Is there a way to save a multi part print if one fails?
I'm printing 6 separate parts in one go, after 4 hours of printing one part failed, but the other 5 are printing nicely.
Is there a way to prevent the print from printing the failed part and continue printing the other 5 parts.
I'm using Cura and an Ender 3 printer.

Depending on the fail you should stop printing as the printer doesn't know a part failed, the molten filament will stick to the next part increasing the chance to fail the next part.

If you use the OctoPrint print manager, you can exclude regions to be printed using the Exclude Region plugin. The description states that it can be used to rescue partially-failed prints:

The intent of this plugin is to provide a means to salvage multi-part prints where one (or more) of the parts has broken loose from the build plate or has otherwise become a worthless piece of failure. Instead of cancelling an entire job when only a portion is messed up, use this plugin to instruct OctoPrint to ignore any gcode commands executed within the area around the failure.

Other print managers may provide similar facilities.
I'm not sure if it will enable you to rescue your current print job.

That is an interesting benefit of a print manager that I had not considered, I learned something today.

That does not work for the OP he is printing now! :-) Unless he is using OctoPrint and the plug-in right now (not mentioned). Cool feature though! Thanks for sharing!

Thanks @Mick I found a demo from teaching tech on YouTube he's using Cancel Object plugin for octoprint that will do exactly what I needed https://youtu.be/Zq1sFBgxy8o

Mick is right that you can do this with OctoPrint and maybe other print managers, and 0scar is right that there's no way to get the printer to stop printing the no-longer-wanted part when printing without a print manager (since it doesn't know about objects). However there is a way to recover and keep the non-failed parts if you're willing to waste material printing the rest of the failed part. It involved having a recovery tool built in advance, though.
Basically, you need an adjustable-height platform you can temporarily glue to the bed where the failed part would have been, small enough not to interfere with other parts but large enough to cover at least most of the area the failed part should have been in. The surface of the platform needs to be something your material will adhere to, ideally the same material you're printing with.
With the print paused and the head parked to the side, glue the platform to the bed and adjust its height using the depth-measurement function of a caliper to match the current layer height. Alternatively, you could use a straight-edge resting on two adjacent printed parts to match the layer height, but that risks dislodging them.
After it's attached and adjusted properly, resume printing.
I have not tested this with tall parts, but I have successfully made such "platforms" with layers of blue tape for small parts, and see no reason the concept should not scale to arbitrary height as long as you can get sufficient adhesion and match the layer height sufficiently well. Designing a sufficiently adjustable and reusable one (with adjustment mechanism that doesn't interfere above the desired height) would be an interesting project.

Building a temporary build platform is also a great idea, you see many pictures of people doing that on Reddit.

Considering your setup, you don't have reported using an external print server like OctoPrint, so the other answers hinting to OctoPrint are a solution if you are upgrading to a print server.

I'm using Cura and an Ender 3 printer.

Your prints are coming from an SD card from a pre-sliced file (note that the OtoPrint solutions require you to pre-process the file after slicing before printing, also if you have a single mesh file with multiple parts you need to pre-process the file prior to printing).
So, no, once you sliced the 6 parts on the build plate in your slicer, the G-code is fixed and the printer will print as the sliced instructions from the SD-card. During printing it cannot skip the code of a part that failed along the way; there is no way to interfere with the printing other than stopping the print during printing.
For that reason, many people don't pack the build plate too full, the more parts, the higher the chance it fails. You could print the part one after each other. Packing the plate with multiple parts is usually not faster than printing one at a time (if it fails you have nothing, otherwise a single failed print).
Depending on the size of the parts you can also tell the printer to print each part on the plate one after another in a single job; note that the printhead dimensions limit this. If one fails you stop the job, but the already printed parts are saved. You can then commence a new print of cut the G-code and reprint the shortened file.

In addition to the previously answered "Exclude Region" plugin for OctoPrint, the "Cancel Object" plugin for OctoPrint also works excellently.

Cancel single objects during a print based on code comment lines
This plugin allows the user to cancel single objects during a print while allowing the remaining objects to print normally. Instructions for use with compatible slicers are provided on the plugin’s GitHub Homepage.

Source: OctoPrint-Cancelobject


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How can I make bed leveling improvements in the middle of my Ender 3 V2 bed?
Got my Ender 3 v2 and stack with the bed leveling.
Used default settings, Creality slicer 4.2, test PLA from the kit and print model https://www.thingiverse.com/thing:3013319 (4 squares in each corner and 1 in the middle), nozzle 200 °C, bed 60 °C.
After some adjustments, I have good solid pieces on the bed corners  but the center one has small gaps. Is it possible to fix this problem?
Corner pice:

Center piece:

With Got my Ender 3 v2 and stack with the bed leveling do you mean you have a levelling sensor? E.g. like an inductive or touch sensor? Or is this a typo, you have a standard Ender 3 and are stuck at levelling?

The gaps are, because the nozzle is to far from the bed at this point. It may sound like a big deal, but actually this is not leveling alone, but it looks like the bed is not a perfect plane/perfectly flat. This is normal, my ikea mirror and my stock bed show the same thing. Now here's one solution:
Print calibration stickers, like you already did on various places around the bed to get a feel, where it is too low. Let it cool and put painters tape (the very very thin tape, that should not burn) on areas, where the bed is too low. Print more calibration rectangles and check if you have enough. Repeat until you cannot see a difference.
It took me about 2h to level everything absolutely perfectly. This was 2 years ago and I didn't have to touch the tape below my bed ever since. It just works.
Alternative solutions involve mesh bed leveling and buying a new bed surface or even the surface below the bed. However, I found that to neither of them work reliably, whereas the simple tuning does what it's supposed to.

If you add tape between the heated bed and the glass, the heat isn't transferred by contact, an insulation layer of air is in between and the glass and bed so the glass will not warm up evenly. Nowadays, Marlin has a feature to probe the bed to adjust for the shape of the bed when enabled in firmware.

Probing for shape doesn't help make the bottom of your prints flat, dimensionally accurate, or extruded by the correct amount. It just makes them adhere. Shimming the bed is the right solution. Uneven heating is a minor issue.

Ender 3 V2 has a default glass bed. I doubt it is not perfect flat for a glass bed.

Given modern ways to produce glas it would be funny if it would not be flat. On a mirror surface (i.e. a steel spring print bed) behind the glass, you would easily be able to SEE the visual distortions - 0.1mm is a LOT of problems for a mirror. Which is why modern glass production techniques are VERY good at making planar glass. Technically not planar, but the earths diameter (no joke, this IS how good they get) is quite straight for something as small as a print surface.

I had exact same issues with my Ender 3 v2. Using the stock default glass the middle would be too far out and I was never able to level it just right - no matter what I did - I could have stayed on it for hours.
In matter of fact, it wasn't just the middle, it was the middle between each of the corner points as well, meaning, imagine a plus sign going across from the dead middle of the bed vertically and horizontally, where all that area would be a little too far out.
I did anything I could, eventually what solved it for me was tightening all of the frame once again, making sure the x-axis gantry doesn't wobble, the hotend doesn't wobble and then realign the gantry nuts below the bed, to help with this alignment I actually tilted the whole printer 90° so gravity will help the wheels get the right alignment.
The issues such as you are describing were gone after complete overhaul tightening as mentioned above.


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Under extrusion
I have a Prusa i3 3D printer and am using Slic3r for slicing.
I've noticed that my extruder is underextruding. I've correctly set the nozzle diameter and the filament diameter and I've already tried to increment the extrusion multiplier (which is currently set to 1.1). As Slic3r suggests this is a maximum value, I'm wondering if there is something else wrong.
Does anybody a have suggestions on which settings I can look at?

It looks like your nozzle is just too far from the bed. Reset the extrusion multiplier to 1.0 and level your bed. Alternatively (or perhaps also) did you configure the filament diameter wrong in slic3r?

If that was the cause, it would only happen on the lowest layer. However, this error occurs on all levels. I measured the filament diameter with calipers on multiple places and configured this value.

Make sure the extrusion width is set absolutely, or is set to 0. Slic3r (and PrusaSlicer) has a bug where extrusion width is calculated over layer height if set as a percentage.

Is the next layer properly extruded? Also, are you printing on cloth?

I have a Prusa i3 pro b, and was having a similar issues. Turns out the spring for the plastic extruder feeder can be too slack. I printed these at 2 mm and put it under the spring and it solved my issue.

It looks like the nozzle is too far from the bed, try leveling the bed again - that should solve the problem.

The nozzle is already fairly close to the bed. Also, this problem doesn't only occur on the lowest layer. For example, vertical walls also very easily split because the different lines of the perimeter don't connect.

It may also be, that your hotend temperature is too low and the extruder 'spins through', so that too little filament is extruded. In that case you would hear some clicking noise.

The hotend temperature is currently set to 180degrees for PLA filament. I don't hear a clicking noise during printing...

I do print PLA on my Prusa i3 pro C with 240°C and it extrudes very well, the clicking noise only appeared at high feedrates for me but the extrusion often was too low at lower temperatures. Just do a bit of trial with the temperature.

Btw I use curaengine in Repetier host as slicer an set the extrusion of the first layer to 40% because the nozzle is as near to the bed, that just a piece of paper fits under it with some friction.

authors: พรชัย สําราญพานิช


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How does 3D printing over USB work?
In Cura, if you plug your favourite 3D Printer you will most likely get an option to Print via USB. If you have never heard of what I'm talking about, please see this video:

I wanted to know some information on how this works:

Is the communication through UART or through Serial?
How can I establish a connection to the 3D Printer?
Is there a list of commands I am able to send?
What is the default baudrate for 3D printers?
How is the G-Code of the print sent to the 3D Printer?

With the Ender models, I think they use an Arduino-compatible ATMega chip, which would use serial.

I’m voting to close this question because it is not a genuine question, but is merely plugging a YouTube video.

I'm not so sure, @Mick . I think it's a genuine question.

@ifconfig OK. I've retracted the close vote. I'll try to draft some sort of answer.

This is just a stub answer. I will try to expand on it later.
The 8-bit microcontrollers used on many 3D printers do not have a USB interface, and so a USB to serial interface chip is used to allow a computer to communicate with the serial port (UART) on the microcontroller. In order for the computer to communicate with the printer, a device driver is needed to allow the operating system to communicate with the interface chip.
The appropriate device drivers should be supplied with your printer, and you should install these drivers before you try to do anything else. The drivers will make the printer look as if it has a serial interface, and the highest speed that most 8-bit microcontrollers can manage is 112800bps.
If the software that you are using has a terminal interface, you can send any G-code commands to the printer. For a list of G-code commands, see here. Note that this list includes commands for CNC machines as well as 3D printers.
For normal printing, G-code commands are sent to the printer using a print manager, such as Repetier-Host. Some slicers may have built-in print managers.

Some boards use ATmega32U which has native USB and can communicate up to 1.5 Mbps without issues of data loss.

The old common baud rate was 115200 baud. All those boards can handle 250000 just fine.


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Scaling mechanism in Creality Slicer 1.2.3 for super small/large STL
I am having a tough time to understand scaling out and in STD files loaded into the Creality Slicer 1.2.3.
For instance an STL like this:
 facet normal -nan -nan -nan
  outer loop
  vertex -0.0515186 0.0260341 0.0015
  vertex -0.0514094 0.0260341 0.0015
  vertex -0.0516411 0.0260341 0.00172995
  endloop
 endfacet

This STL is super small, considering that the default unit for STL is a millimetre, but when I open it in the Creality Slicer it shows me that the model is much larger.
I assume there is some scaling mechanism in the slicer (also for large STL). Do you know how it works? It seems to me that there are some rules. For example, if the max length of the facet is < 0.05, the slicer changes the unit to meters(?).

All STL files I download from e.g. Thingiverse makes me scale the object with 1/10 in Fusion360, so the default must be cm.


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BTT SKR 1.4 Turbo SPI setup
Can anyone confirm that on the SKR 1.4 Turbo you don’t need any of the jumper wires to enable SPI mode? Like you would do on the 1.3 variant?
As I have searched and cannot seem to find any reference to using linking wires.
Also, do you have to manually adjust the output of each driver by the potentiometer? As adjusting the in the screen doesn’t seem to do anything?
Any help in this regard would be most appreciated.
Paul

Yes, that's correct. You don't need jumper wires, communications is done through the jumpers and the board directly.
What drivers are you using?

On the Xand Y I’m using the tmc2130 and on the z I’m using tmc5160

That'll work just fine. No need to adjust the pot on the drivers. Enable "TMC_DEBUG" in your firmware. You will be able to use "M122" to check if the driver communication works fine and if the currents are changing as expected.


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Looking for CAD files of basic crystal structures
I'm looking for basic models of crystal chemical structures. The most basic example would be a cube, it gets harder though as I next need polyhedrons with one of three angles < 90°, then two, etc.
Is there a database of these out there somewhere? Or is the fastest way to make them myself?

You may find that OpenSCAD regular polyhedron library may serve your requirements.

From the linked site:
All polyhedra are centered at the origin and have an edge length of 1.
From the linked site:
Included polyhedra:
tetrahedron
octahedron
hexahedron
icosahedron
dodecahedron
cubeoctahedron
truncated_tetrahedron
snub_cube
rhombicuboctahedron
truncated_hexahedron
truncated_octahedron
icosidodecahedron
snub_dodecahedron
rhombicosidodecahedron
truncated_cuboctahedron
truncated_icosahedron
truncated_dodecahedron
truncated_icosidodecahedron

OpenSCAD is a reasonably easy "description coding" program at the base level. I suspect that for something such as this, it might not qualify for the easy reference.
My search also linked up a few Thingiverse entries, but they weren't as sophisticated as the above and may be a subset of the library link.

Agreed. OpenSCAD is the way to go. There are plenty of crystal and polyhedral libraries for it available online.


text:
Rough vertical ridges
I sometimes have a problem with rough surfaces. This problem can show up any time on vertical surfaces.
In the linked picture of the problem, the area further from the camera has ridges that are sharp and clean. It is usually  in one area on the outer surface of curving shapes. Could anyone tell me what the name of this effect is and how to avoid it? I'm using an Ender 3 and Cura.

have you tightened your belts and checked the extruder ways?

Looks like underextrusion caused by oozing elsewhere or "coasting" enabled in Cura. Can you add all retraction, combing, and coasting settings to the question body?

Looks like under extrusion, here's a extreme example.

I would check your feed rate by marking out 100 mm on the filament then manually extruding 100 mm. You can use this to verify if you are under extruding due to your feeder. If you find that the printer only fed say 90 mm when you asked for 100 mm, you will need to change your feed rate in Cura to 110 %.
If you confirm that the printer is pulling 100 mm through when you manually ask for that much, then it could be a combination of speed, cooling & jitter. I would slow down the print speed and see if it improves the print quality. I've experienced issues where the nozzle is moving fast around small bends and wobbling slightly, the filament is struggling to land on the previous layer and the resulting effect looked a bit like your photo.
I can't think of anything else that might be causing this issue.

I kicked the feed rate up to 105% and replaced the nozzle. These actions seem to have fixed the issue.


text:
How does this multiple-curve-beam flexural pivot work?
I found this in Handbook of Compliant Mechanisms (2013), page 162, or at the start of "Chapter 11, Elements of Mechanisms," subsection 11.1.2 Revolute
I don't understand how it's supposed to go from 1 to 2 when b rotates around c.
The description reads:

This element is a rotational flexural pivot constructed by three
curved beams to achieve a large range of motion. Theoretically, this
element will rotate without axial-drift motion, because of the
symmetric arrangement about the axis.
(1) Rigid body a is fixed. Rigid body b rotates about c-axis.
(2) Deformed configuration
(3) Photo of the device.

It's unclear which part of the beam is attached to what. I can understand how one curved beam could switch its curvature (in general, like they do in  bi-stable latches), but I don't see how they could both at the end of of the rotation end up curved in a way that's opposite to how they started.
How could c2/c3 go from the configuration in 1 to the configuration in 2 ?
Or could they be two different iterations of the same idea ? I can see how (1) or (2) would resist rotation of c around b, and snap it back to its original position.  The text claims (2) is the deformed configuration though. I can also see how (1) with just c1, c3, c5 would deform to (1) with c0, c2, c4 if (b) was turning anti clockwise.
Also, what would be an ideal material to print this kind of compliant mechanism ?

You might get a good answer for how it works at https://engineering.stackexchange.com/ - if you do, let us know, and we can probably recommend materials.

Im reading th ebook right now and it seems to be a bit diffuse on many of the examples. But i would posit that its a typo it should read derived not deformed. I will ct one as soon as our waterjet is again taking reservations.

The picture looks as if there is a printed back surface to which the central part is attached.  If this is not a photo illusion, it would prevent the central part from flexing properly.  There  is a limit to the amount of torque this can transmit, but within the elastic limits of the material it looks like a good design for a shaft coupler.  May print it of nylon or TPU.  I think the two pictures are functional similar, but 2 is not the result of twisting B in 1.

The picture looks as if there is a printed back surface to which the central part is attached.  This can not be the case, since otherwise the curved members would not be able to flex.  Everything inside the outer ring must be detached from the back shell.
Like all couplers, especially flexible couplers, there is a limit to the amount of torque the coupler can transmit.  Within the elastic limits of the material this looks like a good design, and a good match for 3D printing.  The forces are along the layers, not across the layers.
This looks like a good design for a rotary coupler.  I'm resisting calling it a "shaft" coupler since neither side is equipped with any connection to a shaft.  One could modify the design to have a larger central hub with a shaft hole (and set screw(s)).  As it is, there is an implied method to hold the outer ring, and a fairly explicit three-pin adapter to drop into the open slots in the arms which connect to the center.
I would use ABS rather than PLA, although it depends on the stiffness you require and ability to sustein abuse.  PLA is stiller than ABS, while ABS, within the elastic limits, is more compliant.  I am not confident that either of these plastics would stand up to thousands of millions of flexures.
I would prefer to print this of TPU or Nylon.  Both of these are tougher than ABS and PLA.  They withstand greater flex with fewer problems with micro cracks and degradation.  I have printed another shaft coupler of TPU, and it was both compliant and still.
It isn't possible to really nail down a material without knowing the application.
As to your question about one example being a transform of the other, I don't thing they are.  The A and B drawings are similar in function, but are not stressed and unstressed versions of the same part.  Either will work as a coupler.

Thanks. I contacted one of the coauthor of the book (Larry Howell) and he was kind enough to send to the original paper from which the chapter in the book was derived. Those drawings are not from the original paper (and the description indeed doesn't make sense), and the paper shows that this device requires a torque that is linear to the angle of rotation of the inner part around the outer in the possible range of motion of the mechanism; also the deflection (rotation)  is greater than other designs, and other designs also have their torque increase sub linearly... Simulated in ANSYS..

I would try and print it in PLA because it is quite flexible.
ABS is harder in my experience and breaks more easily.
If you are able to print PET, you should also try that for the same reasons.
There might also be better materials I've never heard of, also please leave a comment if I'm wrong with anything.

PLA breaks brittle, ABS breaks after deformation.


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Strange behaviour x and y axis - corner of print
Some background to the problem:
Several months ago I started getting poor print quality in one section of my prints (back left corner of bed) - I diagnosed that the plastic X axis carriage and the right Y axis carriage had distorted from heat over a period of 4 years running my Wanhao D4S, and the linear bearings no longer aligned properly.  I found a long gouge in the right Y axis rod and have replaced this.
I have since replaced all plastic carriages with aluminium to eliminate any potential distortion in the future.
Additionally, the 5 mm rods running in the X direction in both front and back of the printer also had slight bends in them, and I have replaced both these with 8 mm rods to enhance rigidity and prevent further bending problems.  With the bent rods there was a very noticeable vibration.
The issue I am now facing is the front right corner of test cubes I have been printing (see attached photo) are not sharp - they are okay at about the top and bottom quarter, but in the middle it is as if the X and Y axes are not travelling far enough to the front right corner, and the corner is cut off diagonally and tapers inwards slightly like an hourglass.  But as mentioned really only in this one corner.  The issue is most apparent where indicated by the arrows - although the others also exhibit to a small degree the same issue.

I have aligned all belts and pulleys, and made sure the belts are tight enough to "twang" but this does not seem to help.  All pulleys have also been re-tightened.
The printer also does seem to still have a vibration when moving along the Y axis, and is much louder than the X axis movement (which is barely noticeable).
When the belts are disconnected both X and Y axes move by hand smoothly.
Has anyone seen this issue before, or can offer a solution?  My next step was to check stepper driver current, although I don't believe this to be the problem as the issue is very consistent in its placement.
I think also overall, print quality in general is not as good as it once was before the initial troubles with the carriages started.
To help install the rear 8 mm rod, I unscrewed the two Z axis rods, but to the best of my knowledge they are in their original position.  They also move smoothly.

Welcome to 3DPrinting.SE!

Does the problem occur with both extruders?

I only have one extruder working at the moment so cannot check.  However, I have found a grub screw had fallen out of the right hand Y axis carriage holding the rear X axis rod which seems to have contributed to the problem. Since replacing the issue is not so prominent. I am now in the process of replacing stepper drivers.

If the grub screw comes out again, you could secure it with Loctite 222 (or equivalent), which is a low-strength threadlocker. A 10 mL bottle will likely last you forever.

Thanks Andrew for your advice re the grub screw.  Further testing has shown this is not the only issue the printer is experiencing.  I have another printer on order and once that arrives I will decommission the D4S and give it a thorough overhaul and see if I can get results as I was once able.

After one further check (stepper driver current/VREF), which I didn't think could be the problem due to not adjusting to cause the problem; it turns out this actually was the problem.
All stepper drivers have been reset back to correct VREF for their respective motors minus 10% as a safety margin and everything is printing well again.
I have no idea how VREF could have changed by itself, however thermal expansion on the boards due to constant use may be an explanation.
For anyone else experiencing similar issues and who have discounted the stepper drivers as the problem, I suggest resetting VREF to see if that helps.


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Unable to Determine Proper Print Scale of STL model
I am new to 3D printing and have a Monoprice MP Select Mini 3D Printer V2. I wanted to be able to 3D-print this VR Adapter from Thingiverse. Before downloading the Cura software, I tried opening the model in Print 3D, and as you can see in this picture, it appears that the model is just under 100 mm, which is well under the 120 mm limit of the MP Select Mini’s 120 mm×120 mm build plate:

However, when I downloaded Cura and input the specs for the printer (120 mm for x, y, and z dimensions), the model appears to be much larger than the 120×120×120 area. The program tells me that the model is 132.5 mm × 180.6 mm × 36.6 mm:

I need the model to fit the controller for the Oculus Quest, so I can’t just scale it down. Can anyone tell me why I am seeing this discrepancy and how I can still print this model?

The STL format does not define unit information. So there is no way of knowing, from a STL file alone, what size it should be.
However there are only a handful of units people design with. So the unit is most likely one of inches, cm or mm. So if you inverse convert between those combinations you'll likely find the real size.
Your image is somewhat inconclusive. But it seems to indicate your object is in fact larger than your bed. As it it is 18-19 pips of height and i would interpret each as 10 mm from the image. Which would indicate your model is correct.
Split and glue? Print corner to corner you should have 207 mm length that way (but not necessarily width).


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X and Y axes don't move after upgrading to TMC2100 drivers
I had noisy DRV8825 drivers for my extruder E0 and X, Y, Z axes. I upgraded all to LV8729 drivers but they were still noisy, so I bought two TMC2100 drivers for the X and Y axes and two LV8729 for the Z axis and extruder E0. I updated Marlin (reversing endstops logic and choosing driver types) and I removed the jumpers under the driver pins. But my X and Y axis don't move; eventually the printer halts.
What could be wrong?

Enough that this question makes little sense. Did you only upgrade them? As in: The cabling is unchanged? You will need to provide not a photo of the driver, but the code for the relevant settings in marlin for us to even think of answering this.

I found the problem. I'm going to answer my own question.

Looking forward to read what it was.

Steps/unit also must be modified. In my case these values made the printer run silent and smooth.
#define DEFAULT_AXIS_STEPS_PER_UNIT   { 100, 200, 6160, 884 }

I set Max feed rate and Max acceleration as below:
#define DEFAULT_MAX_FEEDRATE          { 300, 300, 5, 25 }
#define DEFAULT_MAX_ACCELERATION      { 300, 300, 100, 10000 }

authors: فيصل الهذلي 2


text:
Does a teflon insert in an E3D V6 clone limit it's useable temperature so it can't print nylon?
I'm new to this game, and recently upgraded the hotend on my Ender 3 Pro to a clone of an E3D V6, as I'm keen to do nylon prints at some point. I noticed however that this one I got has a teflon liner which seems to negate the advantage of a metal hotend entirely.
I'm wondering what temperature it's safe to run this hot end up to?

There are many types of heatbreak clones. In cour case, your clone effectively turns your hotend into an e3d Lite6, not an all-metal e3d v6. To function properly, the PTFE liner needs to butt against the nozzle or you will quickly develop leak and clog issues.
This means, handle it like a Lite6, which has a max of 245 °C listed, but under usual operation should not exceed 230 °C.

It depends how deep it goes. If the teflon goes into the hotend then yes, it will limit the temperature end.
But: the teflon may just be something that ends somewhere in the cold side and sticks out so there is something to put into the extruder or higher up into the connector.
I cam currently setting up a Slice Mosquito for a Bondtech DDX. The Mosquito is full metal, but there is a (actually printed nylon) adapter for the DDS. In this adapter you put a teflon/capricorn tube, that ALSO sticks out only around 5 mm. Here is the point though: it never goes into the even cold side and is only there so the connection to the extruder on top has a width limitation.
So, it really depends how long this tube is (and no-one here will know because a v6 clone may be different internally from the original). I would suggest pulling it out (it should move out easily) and then seeing how deep it goes. As long as it stays on the cold side before the heatbreak, it never gets in touch with anything that is hot.

Long story short, you can print Nylon with a Teflon tube. I've done it. P.S. The nylon absorbs water like nothing you've ever seen. Even after the part is printed, it absorbs water, and expands!


text:
PETG warping - adhesion or temperature too high?
Ender3 v2, SIENOC PETG which advises temperature of 230-250 °C on the box. I'm printing on top of cleaned blue tape, using a temperature of 230 °C for the nozzle and 80 °C for the bed.
I've had all sorts of trouble getting first layer to stick but finally managed it. However the thin end of this hook has now warped and the other end is too.

Looking at the image above, you can see it's much thinner at that end. Should I try a lower nozzle temperature? Or bed? Or both?
The fans are at 50 % (set in Cura), should I have left them on 100 %?

I have to mention that the tape has been cleaned with isopropyl alcohol. I can print PLA no problem direct to the bed but am having so much trouble with PETG - rather than warping this could actually be adhesion problems.
I've tried a higher initial layer (0.3 mm vs 0.2 mm), 0.1 mm Z offset, gapped to 1 sheet of paper as per PLA, then 2 sheets - I've done that 50 mm in on each corner and then checked it in the middle of the bed too. Initial layer is at 10 mm/s and then to 40 mm/s
As you can see in the picture the brim looks rather flattened, but if I give more gap (e.g. 3 sheets) it doesn't even stick at all.
I have managed to print a benchy after maybe 6 attempts, but this was luck and had really poor adhesion, a gentle tap with my finger dislodged it. The actual print was fine.
Tempted to try another PETG but wanted to make sure I'm not missing anything obvious - at the moment I can't even print the brim again because it won't stick.
I'm really confused because a lot of I read suggests PETG sticks really well but I've having the exact opposite experience.

Hi Mark, welcome to 3DPrinting.SE! PETG sticks very well to glass and an adhesive like 3DLAC, glue stick, hair spray, etc. I've printed kilometers of 2.85 mm PETG without any problems with adhesion (on glass and 3DLAC). I'm not a fan of tape, which should not be the go-to solution nowadays with all the much better alternatives available, BuildTak (and clones), PEI sheets, glass, 3DLAC, DIMAFIX, etc.

@0scar thanks for the welcome. I did try a gluestick on the smooth side of the glass and just straight on the glass (cleaned with isopropyl), neither stuck. Last night I was trying a bed test that prints squares to check level, they printed mostly ok but there is no adhesion, the corners stick but even then rubbing your finger over them will dislodge from the bed. Starting to wonder if the temperature is too low and its set by the time it hits the bed

I do 240 °C for the first layer, bed 70 - 80 °C depends on the printer I choose. Note that not all glue sticks work, only those with the secret ingredient. Read about secret ingredients here.

Hello @Mark, I noticed your question has been up for a while now. Have any of the answers below been able to solve your question? If so, would you mind accepting the appropriate answer. If not, what is missing so that we may help you further? Also, if you have figured it out on your own, you can always answer and accept your own solution. Thank you.

PETG is a pain to print with, but adhesion/warping usually isn't the issue.
To begin with, fan should be completely off for PETG unless you hit problems that necessitate a fan, and then only minimal. Certainly not 50% or 100%. Fan will seriously impact adhesion between layers and give you brittle prints. It also might be responsible for the warping you're seeing, but the biggest issue here is that you have an adhesion problem.
I'm not sure if blue tape is generally recommended for PETG. The Buildtak clone that came with my (original, not v2) Ender 3 adheres extremely well (if anything, too well) with PETG so I've never worried about adhesion with it. But if it's not adhering to your blue tape or v2 coated-glass bed (or if you're concerned about ruining that bed from PETG adhering too well) you need to find something it will adhere to. I'd suggest getting a Buildtak-clone Ender 3 v1 bed surface (you can find these cheap) and clipping it to your bed (since you presumably don't want to glue it over the v2's much nicer bed).
I guess I should mention that distance to build surface could also be the issue. Make sure the bed is leveled correctly. I don't like the paper method because it's too imprecise; the best way I've found is to move the Z axis to 0.1 mm and adjust until 0.1 mm feeler gauges fit under it with some friction and 0.15 mm ones don't fit at all.

Thanks for the help. I'm going to get some metric feeler gauges. I have tried various bed levels but its always the same - just doesn't stick. I'll try with fans off - it does make me wonder if 230 is too low for this particular filament and combined with the fans its too cold when it hits the bed and thats why it doesn't stick. Need to upgrade bowden tube to go hotter from what I read. Maybe a buildtak is the answer. Thanks for the reply!

@Mark - No need to use metric feelers, SAE ones work just fine. a 0.1 mm feeler is almost exactly identical to a 0.004" SAE feeler, and a 0.15 mm feeler is almost exactly identical to a 0.006" feeler. Both are very readily available. But, metal feelers don't actually provide anything that paper feelers do and ordinary printer paper is 0.005" (0.125 mm) thick. It's easy to get the feel for paper feelers; you're looking for resistance that interferes with pushing the paper but doesn't interfere with pulling it. When it's just right, pushing the paper makes it bow upward before it slides through.

I find bed adhesion is fine with blue tape at 70 °C. PETG doesn't like to be squished onto the bed like PLA, so try using something like a business card to level the bed.
Try printing with a brim (I believe what you used in the picture is a skirt; you want the one that is attached to the part) and start with no cooling. Ramp up cooling to the minimum you need for good print quality.

The proper way to optimise bed temperature (which depends on material, sometimes brand, bed material) is to follow these instructions which basically consist in:

print a wedge multiple times changing only the bed temperature
pick the temperature where the adhesion is the best.

Typically PETG works with 50-70 °C bed temperature. 80 °C is likely too high (unless the surface of your bed is much colder than the temperature sensor) because PETG is floppy (soft) at that temperature, and the first layer should be rigid enough to stay flat after the upper layer will pull up (as explained here).


text:
Printer crashes at the beginning of a print
I am converting an old Makerbot Replicator 2 to Marlin Firmware and everything works. The printer heats up, auto bed levels, and starts the print. However, after a couple minutes (usually after the 1st or 2nd layer), the printer crashes and stops. It does not continue printing and I have to restart it again. It crashed for every single print, I have not had any successful prints yet.
Here is a video showing the issue:

The camera was started right when the print started. After about 1.5 minutes, the printer crashes, and the LCD screen freezes.
Here are photos of a couple of prints that crashed:

I have all of my code here: RosalieWessels / Marlin_MakerbotReplicator2
My models are sliced with Cura and printed in PLA.
I tried hotend temperatures of 200, 210, and 220 degrees C. My print speed is around 50 or 60 mm/s.
Here is a sample sliced file that was used:
https://filebin.net/df33a3jjwgemz0m8

I want cake too! https://youtu.be/MzcrX3wcA-Q?t=32

One thing you should fix is the attachment of the belts to the carriage; the belt (tensioned with a tie wrap is quite original) has a lot of play. This causes the layer shifts in your prints. But, I don't think this is related to the crashing.

Can you measure the voltage draw of heater and bed?

Hello Rosalie, I noticed your question has been up for a while now. Have any of the answers below been able to solve your question? If so, would you mind accepting the appropriate answer. If not, what is missing so that we may help you further? Also, if you have figured it out on your own, you can always answer and accept your own solution after 48 hours. Thank you!

The filebin link seems to be empty or dead.

Few things to try,
Check G-Code - Verify that the slicer is not the problem, slice using some other program / make a new default profile and re-slice.
3D File - Also In parallel with the above point, I would get a standard test cube STL to start with. This will be a simple quick print to get a solid reference.
Voltages - Get a Multi-meter on the Regulated Voltage rails, 5V Rail, 12V rail / 24V rail. See if at the moment of crash a voltage rail collapse, the most likely one would be the microcontroller rail, but you may be able to see the problem somewhere else.
Current - If possible, measure the current draw of the printer either from the mains or after the AC/DC regulator. Its possible something is going horribly wrong and current limiting.
Serial Port - Possibly connect the printer to a PC via its serial port and open a com port. See if the printer spits out an error code at the time of crash?
End Stops - Double check that none of the End Stops are accidently being triggered (Although this should not crash the system, it might be part of the problem)
Verify Sensor Readings - Check all end stops, check the bed temperature readings, check the nozzle temperature reading. Maybe a sensor has failed and is causing the controller to crash out.

of your suggestions, only the voltage and current could be relevant, because the rest would have resulted not in a crash like that, it's a print from SD-card afaict, making Serial port a non-issue, the file wouldn't result in a hangup, the G-code does not result in a self-reset/bluescreen, endstops are ignored during actual printing (printers use software endstops only then)

@Trish: While the serial port isn't being used for printing, it could spill useful debug output indicating the cause of the crash at the moment it happens.

+1 for serial port debugging, you could put more emphasis on that option. I am surprised that no one else mentioned this.

I see a couple likely culprits for a hardcrash like this

problems with the power supply. If the power supply does not provide enough voltage an/or current to the board, this can lead to a lockup of the board.
temperature issues of the board. If the board overheats, it could fail to execute properly, leading to abort. make sure that the board is not overheating.
faulty firmware. recompile your firmware and reflash it.
faulty board.

If you compiled your own firmware using visual studio code, use platformio's inspector found on the platformio homepage to make sure there are no memory overrun issues. You must read the whole prompt because sometimes it will not explicitly state that there is an issue


text:
Gaps between perimeter walls; potential under extrusion?
The cube is a 2 cm x 2 cm with infill at 30 % and layer height 0.2 mm, more details can be seen below.
I'm printing with PETG using an Ender 3 printer.
There seems to be a gap between the perimeter walls, I have already referred to other forums and specifically: " How to fix wall separation in 3D prints (gaps in between wall perimeters)? ", but I still can't find a solution for it.
Most would suggest to tighten up the pulleys, I've tried that, but that didn't work. Others also suggested tweaking to a higher temperature, again I've tried from a range of 230-250 °C, but this also failed.
Infill and initial/top layers seems to be strong and all lines are bonded except for the perimeter walls.
More details regarding the problem:

Here are my print settings:

As an aside, travel speed of 150 will ruin PETG prints if there's any travel over already printed material, including combing. You should set it below 60.

Welcome to 3DPrinting.SE! Hope we can fix it here for you! Regarding: Infill and initial/top layers seems to be strong and all lines are bonded except for the perimeter walls. Sorry, but no way does that look normal in your photos! I don't think a slight over-extrusion will help you here, judging the top infill of the cube you are severely under extruding.

@R..GitHubSTOPHELPINGICE I always read that high travel speed is useful with PETG to reduce stringing, together with high retraction speed. Why would it ruin prints?

@FarO: Explanation here: https://3dprinting.stackexchange.com/a/13808/11157. In general, though (with other materials; for PETG it's just counterproductive), high travel speed is at best a workaround for stringing you haven't solved by fixing the root cause. If you don't have errors leaving pressure at the nozzle, it should not be hard to move across the entire bed of typical-sized printers at 30-40 mm/s without any oozing.

PETG filament is not entirely rigid and compresses slightly in the Ender 3's extruder gear and Bowden extruder setup. Tightening it will only make this effect greater. Being compressed at the point where mm of extruder advance is applied means less than the desired advance of at-nominal-diameter filament will take place. I find I need a flow of 104% to compensate for this.
When adjusting flow in Cura, make sure you get the main flow setting not the first-layer one (which is an additional factor on top of the main one and can be left at 100%), and that all the derived flow settings for each type of extrustion (walls, top/bottom, infill, etc.) all come out matching the value you set. When I first tried fixing this with flow, they didn't propagate right and I ended up testing changes that weren't actually doing anything.
With that said, you may have something else going on too. The underextrusion looks pretty severe, including in the top layers which you said looked okay. You should not see deep grooves between the lines like that. I suspect they're only bonded to the layer below, not to their neighbors. This could be a result of tightening the extruder pulley, or some other problem.

Very interesting the compressing/biting of the extruder gear! Knowing I'm printing a lot of 2.85 mm PETG, my gears are also very tight biting the filament, but, I've never had to adjust flow. I guess that's a benefit of using much thicker filament?

@0scar: I would guess so. FWIW initially I didn't even notice the underextrusion with PETG but it was a big issue for TPU where the factor was 13%. I then thought to check it for PETG to see if it might be related to my layer adhesion issues, and indeed I found I needed an extra 4% for PETG to extrude the nominal amount of material. This made sense in terms of their relative compressability.

I agree with @R.. GitHub STOP HELPING ICE, looks like under extrusion you could try a flow rate test print like this link to try and dial in the value.
But probably worth just trying a flow of 105% and see if it solves the problem. Another thing worth verifying is that your printer is feeding accurately. You can mark out 100mm from the feed hole, then manually command the printer to extrude 100mm, then measure the distance from the 100mm mark. This will tell you if you have a feed problem.

If the problem is as I described, OP should see a feed problem reflecting the 4-5% difference. Don't try to compensate for it with Esteps mess, though; this leads to all sorts of problems. Just adjust flow or compute a corresponding adjustment to filament diameter - conceptually, the issue really is filament diameter, i.e. that the filament is slightly narrower than its nominal diameter where it's squeezed between the extruder gear and pulley.

@R..GitHubSTOPHELPINGICE Four or five percent aren't going to help the OP!

@0scar: I wonder if OP tightened the pulley so much that it's compressed a lot more. OP's pics look like what I had with TPU and no flow adjustment, where the magic number ended up being 13% (because TPU compresses a lot more in the gear).

Otherwise I can't think what the issue could be, if OP's not hearing clicking/grinding. My normal go-to cause would be oozing material where it doesn't belong, but that's not going to be happening with 7 top layers - there's just nowhere wrong for it to go.

Yes, I have already tried tuning up the flow rate up to 110%, the problem still persists, I have yet to try above that. I have also done some research and many people said that heating the PETG too high could possibly shrink it? Is this one of the factors that could possibly made the gap between the walls? As I have yet to try on decreasing the temperature below 230, below of which it is rated at.


text:
How important is it to move the printer's controller board outside of an enclosure?
I am building an enclosure for an Ender 3 Pro printer, and am planning on the power supply and LCD unit being outside the enclosure.  How important is it to move the printer controller (where the SD card is inserted) outside the enclosure?
Would leaving it in place affect its longevity?
Answers to the first round of comments/questions:

I expect to be primarily printing in the 200C-270C range.
I'm not worried about losing heat from opening the doors - I'll be putting the SD card in prior to initiating printing.
I'm thinking the stepper motors are somewhat of a moot point, there's no way I could move them outside of the enclosure.
My printer is all stock.

What will the temp inside the enclosure be? Is that safe for your board? Will opening the enclosure to load the SD card release your warm air?

It's not just a question of lifetime of the board, but whether the high temps might cause failed prints due to stepper drivers shutting down from overheating or other similar issues.

Also depends on the drivers used - how much heat the drivers will add. Still using the stock board?

It depends on what kinds of prints you make, and especially what kind of materials you want to use.
Certain materials (ABS especially, but also PETG to some degree) will print much better if the entire build area, which usually includes the printer chassis and controls, is enclosed to protect from drafts and allow a much higher ambient temperature.
If you print often with these materials, and the control board is included in that enclosed area, you will significantly reduce the life of the electronic components, especially the capacitors on the board1.
On the other hand, if you print mainly with PLA, which is not as susceptible to issues requiring an enclosure, and prints better with an ambient temperature closer to room temperature, you can put the electronic controls wherever you want.

1 See especially this excerpt from the section on "Premature Failure":

Electrolytic capacitors that operate at a lower temperature can have a considerably longer lifespan.

This guy placed the whole Ender in a 100C environment but he emphasises how important it is to leave the electronics cool:

authors: عقیل محمودی زیاری