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Thermal Runaway issues on Ender 3 Pro even after replacing thermistor and heater cartridge
I have an Ender 3 Pro with the BTT SKR E3 V2.0 mini with Marlin firmware 2.0.8.2.x.
I am trying to print PETG, which requires decently high temperatures.
I initially replaced the stock board after a thermal runaway event that seemed to have damaged it. After installing the new board and getting all the settings dialed in (typically 260 °C hotend and 90 °C bed), it worked great for about 2 weeks until I got the thermal runaway event error again.
Here is what I have tried so far

replaced the thermistor with this
replaced the heating cartridge with this
replaced the hotend with this an all-metal one
measured voltage coming from the power supply and coming out of the board going to heater cartridge (both ~24 V)

I PID tuned the printer using M303 E0 S260 C10 and stored new PID values in EEPROM + firmware. A note, running this multiple times seemed to constantly increase the P and D values. I stuck with the initial values given (kP 13.97 kI 0.84 kD 57.96). I still continued to get thermal runaway events.
I then tested the heater cartridge and thermistor with my multimeter. The heater was 13.5 ohms which seems about right. I was unable to measure the thermistor value. Searching online shows I likely need a better multimeter to do so. It's possible it is bad, but I find that hard to believe considering this issue was happening prior to my replacing it.
Example log of the failure happening. All I did was heat the printer up, leave it on for a bit, set it to cool down briefly, then tell it to heat up again. The printer was heated for ~5-8 minutes before this log starts.
Could this be the board again, or is there something else I'm missing?

I'm fairly certain I have solved this issue, and it ended up having nothing to do with the printer and everything to do with what it was plugged into!
I had it on a smart outlet with some automations set up to kill the power if there was ever a fire. Unfortunately, the outlet I was using was only rated for 8A, while the Ender 3 Pro can draw up to 15 amps. When it was unable to draw more than 8A to heat the hotend, this likely caused the printer to think there was a problem, triggering the thermal runaway failsafe.
After moving it to an outlet with a higher amperage rating, I have had no more issues.

Recv:  T:224.24 /260.00 B:88.95 /90.00 @:127 B@:127

You are trying to achieve too much!
The maximum rated temperature for an Ender3 is 260 °C, yes, but to achieve this you need to insulate the heater block with a silicon sock from losing heat to the surroundings and with some tinfoil from an airstream over it from the cooling fan. And even then, you are trying to work at the absolute maximum the printer can theoretically reach - which means it is above the temperature you can operate it while printing.
Likewise, you try to have the bed at 90 °C and that is too high to consistently reach with the heater installed.
To print at those elevated temperatures you need different gear:

You absolutely need a heated chamber.
You need a specialized hotend that does not suffer heatcreep and is rated to at least 275 °C
The rest of the printer needs to be able to work at those elevated temperatures.

I have a silicone sock on the hotend. Also, If you read through the link for the hotend and heat cartridge I linked, they are both rated for well over 300° C. In addition, I have the printer in an lack enclosure, so while it's not actively heated, I would think it should be sufficient. Also, this issue is definitely with the hotend; you can see it in from the linked log.

I run a small print farm made up of Ender 3's with SKR Mini 2.0 boards. We print ASA, ABS, and Nylon with Nozzle temps of 245-260 °C and bed temps of 105 °C. This is all done without a heated enclosure. There is no reason for your Ender 3 to not be able to do this as well.
My first check would be the attachment of the thermistor to the heat block. Any chance this got dislodged and isn't taking accurate measurements? Does it have a good thermal connection to the heat block? I haven't seen this type of thermistor before. How does it connect to the hotend?


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What are the risks of leaving to print overnight?
I'm new to 3D printing and I was wondering about the risks of leaving my printer to print overnight? I'm aware that if something goes wrong I'll wake up to spaghetti for breakfast but what are the other things like having the nozzle and bed heated that long? And, when it's done it just sits there on so what could that do to the screen? What if the printer runs into some physical problem and damages itself and/or the print? I'm not looking for answers to these questions specifically just feedback on what I should do when printing overnight.

Presuming that you're talking about an 8 hour period, your printer should be designed to run for 8 hours continuous anyway, so nothing will happen regarding the bed or screen that wouldn't happen with a normal print.
If the first few layers stick to the bed, it's likely that you're print will at least be partially completed. So even over night it won't be a full 8 hours of printing while failed. Maybe half that period.
If the problem is bed adhesion, or anything that doesn't effect the filament being supplied to the nozzle, then your only problem will be wasted filament and disposing of the spaghetti. No harm will come to your printer.
If the problem is a break in the filament or filament runout, or a blocked nozzle then you could have damage to the head of the nozzle from printing dry. If you're printing with PLA this isn't really something that you need to worry about too much as you can run a printer dry for several hours without any problems.
If you're printing with ABS or something that needs a hotter head then you could cause damage to it if it's allowed to run dry for an entire night. But again this isn't really something that you need to worry about unless it's running dry for 4 or 6 hours.
Simply checking in on it once in the night should be enough to prevent any problems.

I've run printers with jobs over 2 days, no problem. Note that my Ultimaker 3 display does show some burn-in phenomena.

Also, ensure that your printer has "thermal runaway protection" in the firmware. Different manufacturers probably call it different things, but the idea is that it will shut down if the temperature of the hotend is outside an expected range as determined by the power being put into it.

Oh you can very much destroy parts of your printer with spaghetti. I once had parts of the spaghetti adhere to the hot end case so eventually it started forming a blob that started moving into the case eventually blowing the part cooler apart and the BLtouch was also ripped off the case. Its bad luck, but it can happen.

I've done 4 day prints with no issues.
I just have my printer in a place where there is nothing that can catch fire in the unlikely event that it decides to start burning.
For the rest it's just like any other electrical appliance. Common sense like not having it where things can obstruct moving parts etc,.

Assuming the printer is operating correctly, there are no lifetime/wear concerns from running it that long. Many-hours and even -days prints are normal usage, and print-farms run as businesses run these things basically 24/7 for months on end, modulo routine maintenance. Having the heaters on for 8 hours is really no big deal.
Of course, that's assuming the printer is operating correctly. If not, there are various things that can go wrong.
The worst possible is thermal runaway: the printer losing track of the bed or hotend temperature and running the heating element always-on until it melts the metal. This is a severe fire hazard. Printers with properly built firmware have thermal runaway protection to perform an emergency-stop and turn off heaters if they can't detect a reasonable temperature measurement response to operating the heater, but some popular machines have this feature intentionally turned off by the manufacturer. If you will be operating your printer unattended, absolutely make sure you test that thermal runaway protection is present and working (there should be good ways to simulate it and see that the safety is triggered).
Even with thermal runaway protection working, there is a very slight chance the power mosfet controlling a heater fails in a way that leaves it always-on, which the firmware cannot protect you against. For this reason you also want to have the printer away from flammable materials and may even want an active fire suppression system (there are "balls" you can hang above your printer that activate and release fire suppressant if it's on fire). This is a very low probability event - I've never heard of it happening - but I'm including it for completeness.
Now, the less severe stuff. As long as the first few layers go down well, it's unlikely your print will detach from the bed mid-print, but it can end up having (usually small) parts that warp upward and collide with the nozzle. This can cause lots of different types of problems:

Dislodging the print from the bed

Producing skipped stepper motor steps, which later can cause the print hed to collide against either end of its motion range due its logical position mismatching its new physical position.

Breaking parts of the toolhead, like fan ducts, fans, bed probes, silicone socks, etc.

Causing extruded material to be forced upward into the area around the hotend (e.g. between the sock and the heater block), producing a giant blob of plastic intertwined with toolhead parts and difficult or impossible to remove without damaging stuff.

Most of these things do not impose any major safety risk like fire, but they can do varying degrees of damage to the printer, requiring repair or at least maintenance. For example endstop collisions themselves usually don't damage anything but they might knock your frame out of square/alignment, requiring tinkering before the next print.

The fire-extinguishing balls you describe are almost always designed to deal with kitchen grease fires.  Often, they've got the wrong chemicals for extinguishing a burning printer, and even when they do, they're designed to deal with fires on a flat surface, not fires on a three-dimensional structure.

@Mark: I recall seeing some that were marketed specifically for 3D printers, but it's been a couple years since I looked at them and don't remember the details.

There are software solutions like "Spaghetti Detective" (recently renamed to "Obico")  which can watch your print via a camera, and potentially stop the job if it looks bad.
Most of the time my print failures come early, in the form of poor bed adhesion - watch the job start for a while before leaving it.
I can also remote-check my cameras and stop the job if required, but that requires me to look.
The second most common failure is lifting from the base at any time in the print, so you have to keep an eye on it.
Filament feed issues are probably third on the common list of causes for problems, including running out.
I also have occasional issues where my Pi running Octoprint just looses connection to the printer, and it freezes in place with the bed/nozzle heaters on.  This is just a waste of power, so a future plan is to wire the printer through a relay allowing me to power it on/off from octoprint's web page.
My longest print was ~30 hours - you have to learn to not touch it unless there's a good reason.
Finally, try and maintain the environmental conditions to be fairly constant.  I have an enclosure even when printing plain PLA, becuase my printer's location is in a garage, and opening the main door allows the air temp to drop quickly.  This would upset a running print until I surrounded it.
You can also make sure there's a smoke or heat detector in the room where the printer is, for added peace of mind.

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

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What do I do when my magnetic bed looks like this after a failed print
I'm having a lot of issues leveling my printer and one failed print came out like this. Is there something wrong with the surface that I need a new bed? This happens to me quite often and I literally can't get it off.

What type of filament are you using?

PLA, don't know the specifics but its silk gold

Interesting, I had heard that some filaments adhere really well to PEI sheets, but not PLA. Maybe the nozzle is too close to the bed and therefore sticking too well.

Are you asking what is causing the filament to stick? or are you asking if the adhesion is not working properly and therefore need to get a new magnetic bed?

yes I'm wondering if I need to get a new bed if it gets out of hand

I have edited your question a little bit for clarification. If it is not to your liking, feel free to roll back the edit.

@desperrrr: Even if you did, it would just be a new bed surface you'd need, not an entire new bed. This is a good spare/consumable item to have on hand in advance in case you mess yours up worse than you did.

@agarza: That's not PEI. It's textured "buildtak clone".

Have you seen Options for removing failed prints? This question is pretty similar with regards to removing the print residu. If the sheet is too much damaged, you should replace it.

Print the print once more. the first few layers will adhere to the excess material and you can then peel it all off.

Welcome to 3D Printing SE and thank you for your contribution. This sounds more like a comment than an answer. Also, when you get a chance, please take the [tour] to understand how the site works and how it is different than others.

This is the answer though.

If it's flat so you cannot scrape it off you can just print over it. No need for a new bed.
Check your levelling first because if it's sinking into the bed then the nozzle is far too low and you can end up with a scenario where it rips the bed material when you remove a print.

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


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Software to Pose and Export FBX Character
I am a beginner and looking for software to easily pose a 3D character, which I currently have in an FBX file, and export the pose to an OBJ file.
For example, I could move the character's arm upward, then export that as an OBJ and print it.
Every software I know of either can not pose FBX characters (such as Fusion360) or can not export poses (such as Blender). How can I do this easily?

If you pose it in Blender you can export it and print it with the pose. It's very simple, you just export as a STL file and then print.


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Nozzle scraping bed on Ender 3 with CR Touch
I just got into the world of 3D printing and I'm extremely new to it and everything related and I'm not 100 % sure what I am actually doing (like all the code stuff too). I did one successful print on my Ender 3 (Benchy) before installing a CR Touch and unfortunately haven't been able to print since then due to many problems (about 2 weeks ago).
A bulk of the problems were caused by bad Creality firmware (SD card not recognized, no settings saving, mobo freezing during print). I downloaded TH3D's Unified 2 firmware and compiled it for my board/CPU (4.2.2 board, GD32F303 RET6) which appears to have helped. I also changed default_envs = line in the platform.ini file to GD32F303 RET6_creality_maple but I wasn't sure what to do after that so I just hit build? (in VScode). I built the platform.ini file before I built the configuration.h file, not sure if relevant either.
The problem now is that whenever I try to print something, the nozzle slams down into the bed and cuts deep grooves all over it. It does this when doing the filament purge line off to the side and when trying to print the actual object. I believe I have leveled the bed correctly, I bought yellow bed springs, and I manually leveled before I set up the CR Touch (by manually leveled, I had to actually move the nozzle to the 4 corners through the Move Axis option in the menu as I tried running CHEP's bed leveling G-code (the M25 version for 32bit board) but my printer would just say "Printer Paused: Parking" and then freeze)
I tried adding the X/Y probe offset in the Marlin firmware but even though I managed to flash the edited firmware, the offsets wouldn't stick (I uncommented the right options I believe for it as well). I managed to push the X/Y probe offsets through with Pronterface. I put them as X -45 and Y -5 for mine which I measured manually but am not sure if it's correct). I set the Z offset as -4.1 (baby-stepped until I could barely move a piece of paper) and I stored settings, so whenever I turn off and on the printer, I check the setting and it's still saved to -4.1. After I set up the Z-offset, I go to Motion > Level Bed and the printer does its 9-point probe, but I don't see an option to store settings after the bed level as I do in other people's menu. If it helps as well, I have also tried scaling back the Z-offset (so from -4.1 to -3.5 to -3 to -2.5) but it continues to kamikaze into the bed).
I put a G29 code after my G28 code in Cura, so the printer does a 9-point probe before each print and then proceeds to slam into the bed. I'll post my M503 result and slicer G-code below for anyone interested.
Sorry for the long post, but I hope I included enough information, I just want to be able to print :(
M503 results
> M503
SENDING:M503
- echo:; Linear Units:
- echo:  G21 ; (mm)
- echo:; Temperature Units:
- echo:  M149 C ; Units in Celsius
- echo:; Steps per unit:
- echo:  M92 X80.00 Y80.00 Z400.00 E95.00
- echo:; Max feedrates (units/s):
- echo:  M203 X400.00 Y400.00 Z15.00 E200.00
- echo:; Max Acceleration (units/s2):
- echo:  M201 X2500.00 Y2500.00 Z500.00 E5000.00
- echo:; Acceleration (units/s2) (P<print-accel> R<retract-accel> T<travel-accel>):
- echo:  M204 P1500.00 R500.00 T1500.00
- echo:; Advanced (B<min_segment_time_us> S<min_feedrate> T<min_travel_feedrate> X<max_x_jerk> Y<max_y_jerk> Z<max_z_jerk> E<max_e_jerk>):
- echo:  M205 B20000.00 S0.00 T0.00 X8.00 Y8.00 Z0.30 E5.00
- **echo:; Auto Bed Leveling:
- echo:  M420 S0 Z0.00 ; Leveling OFF**
- echo:  G29 W I0 J0 Z-7.40950
- echo:  G29 W I1 J0 Z-7.29150
- echo:  G29 W I2 J0 Z-7.17500
- echo:  G29 W I0 J1 Z-7.15250
- echo:  G29 W I1 J1 Z-7.10900
- echo:  G29 W I2 J1 Z-7.06200
- echo:  G29 W I0 J2 Z-7.09100
- echo:  G29 W I1 J2 Z-6.95900
- echo:  G29 W I2 J2 Z-7.09000
- echo:; Material heatup parameters:
- echo:  M145 S0 H200.00 B60.00 F0
- echo:  M145 S1 H240.00 B100.00 F0
- echo:; Hotend PID:
- echo:  M301 P28.72 I2.62 D78.81
- echo:; Z-Probe Offset:
- echo:  M851 X-45.00 Y-5.00 Z-4.10 ; (mm)
- echo:; Filament load/unload:
- echo:  M603 L100.00 U100.00 ; (mm)

(I highlighted the line that seems off)
Cura G-code
> ; - Ender 3 Custom Start G-code
- G92 E0 ; Reset Extruder
- G28 ; Home all axes
- G29 ; ABL
- G1 Z2.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
- G1 X0.1 Y20 Z0.3 F5000.0 ; Move to start position
- G1 X0.1 Y200.0 Z0.3 F1500.0 E15 ; Draw the first line
- G1 X0.4 Y200.0 Z0.3 F5000.0 ; Move to side a little
- G1 X0.4 Y20 Z0.3 F1500.0 E30 ; Draw the second line
- G92 E0 ; Reset Extruder
- G1 Z2.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed
- G1 X5 Y20 Z0.3 F5000.0 ; Move over to prevent blob squish

sounds like your flashing didn't work properly, is there a reason you can't return it? Why are you not using the Creality firmware anyway?

The general consensus appears to be that Creality firmware is a hot mess. I can definitely testify to that. Allegedly the GD32F303 RET6 in my board isn't the usual standard one used for other Ender 3's due to the chip shortage / sanctions, and Creality hasn't updated the firmware for it.

Hot mess? Consensus from whom? It was working until you modified it according to your question.

Sorry, hot mess as in not working. Consensus just from looking around on different forums, bad creality firmware seems to be a common issue. It was working without the CR touch, but once installed it no longer works. I know it's not necessary at all to have one but I do want to find out what has gone wrong so I can learn more about printing.

I suggest you revert to the state where it was working as your first troubleshooting strategy and then use that as a state of reference.
Then make your changes one by one rather than try and fix a modification that doesn't work with another modification you're unsure of.
It's better to learn things systematically from a set point than to mix and match randomly. The danger is that you can eventually make your point of reference unachievable which is only fine if you have an alternative working solution. And you're not really learning anything that way.

Yeah I think I'll take the Cr touch off, flash new firmware and see if I can go from there. It's just been so frustrating that finding out the cause of the problem would be a huge win :(.


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Saggy vase walls. What are the tricks to successful vase mode printing?
I've tried printing in vase mode (or "spiralise outer contour" in Cura) and while the floor looks fine, the vertical sides look "saggy"
I'm using a 0.4 mm nozzle, with eSUN PLA+ at 218 °C and a bed temp of 60 °C.  This combination works fine for normal printing.   Layer height is 0.28 mm (Low Quality mode in Cura) with a line width of 0.4 mm
  Image is backlit by a monitor to show the laciness in the walls.

The original model was a 1x1x6 Gridfinity bin that uses less plastic than the original.
https://thangs.com/designer/LittleHobbyShop/3d-model/%23gridfinity%20Vase%20Mode%20Single%20Box-65828

Is this insufficient cooling, or too fast a print speed letting the filament sag under gravity before it cools?  Or is a 0.4 mm nozzle too small?
This reminds me of brickwork where the mortar is too wet.  The bits that work right look fine, but all four sides have bad parts.
What's the trick to vase mode printing?

You likely hav a mix of insufficient cooling and excessive layer height for the overhang angles in that model.
Cooling: The amount of heat you have to displace per unit of time is proportional to the amount of material you extrude per unit of time, which is the product of layer height, line width, and print speed. Going slower is one way to fix this, but not necessarily the best.
Overhangs: The model seems to have walls that tilt outward at 45°. This means, if the layer height were half the line with, only half of the extrusion line in the new layer would be over top of material from the layer below; the rest would be overhanging. But you're using 0.28 layer height. This means only 0.12 mm of the new line, less than 1/3 its width, even touches the line below. This is going to give you at best a very weak print, and likely troubles like what you're seeing.
I would go with thinner layers, and the same or wider line width, possibly at lower speed. Wider line width (note that you don't need a wider nozzle to do wider line widths) will improve the amount of overlap between layers, but it does increase the amount of material you need to cool. My preferred options for that print would be around 0.16-0.20 mm layer height, 0.5-0.6 mm line width, and whatever speed your cooling can handle.

The trick was to change a lot of settings and save as a separate set.
What works for "normal" prints does not work well for vase-mode work.

I had to:

Decrease layer height from 0.28 mm to 0.20 mm
Increase line width from 0.2 mm to 0.6 mm
Drop speed from 125 mm/s to 80 mm/s (though this could be tweaked upward I suspect)

Vase mode also cannot deal well with printing multiple parts at the same time, and if you use "one-at-a-time" mode in your slicer then the max height caps out at 25 mm for me, which is not a lot of use.


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PLA Globbing up on the Extruder Nozzle
My Ender 3 was printing great. However, I'm now getting all sorts of globbing up on the Extruder nozzle. This is causing the prints to fail, and if I come back after a print I'm often getting 1/3 of the print printed with gaps, etc before it totally fails. Any idea what is going on? Its the same roll of PLA that was printing fine at this temperature, etc; but we are getting down to the last 15% of the roll if that matters.

------------------- EDIT With More Information ---------------
Switched out the PLA and my printer is printing great again! Per the suggestion from someone, I'm currently baking the old PLA and will report back on the results!

Does it happen with another roll? If not, wet filament is a likely culprit. Being wet makes it print like your hotend is 20-30 degrees cooler, which would give poor flow and poor adhesion, leading to stray material all over the place happy to get stuck to the nozzle the next time the nozzle passes over it.

Just ordered another roll to see. Currently, its the only roll I have.

I would think the filament has absorbed too much moisture. You can bake it and then try again.
I bake 2 hours at 50 degrees which works ok for me. But the first time I did this some of the roll tried to fuse together and the innermost 1/4 was wasted. So I've found that it's best to loosen the filament on the roll before baking if it's not that much. If it's a full roll I actually unwind it onto an empty spool and roll it loosely.

Nice answer. I've found that some manufacturers wind their rolls with too much tension, which drives the filament to deform and try to fuse when dried... which is rather infuriating. Better ones don't seem to have this problem.

Best of luck with the experiment.

BTW, I know its been awhile later; but looping back I took the roll of filament and put it in my wife's dehydrator for 2-3 hours. It worked great after that.

@Doug nice outcome, thanks for letting us know


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Volcano hot end adapter orientation?
Now that V6 nozzles are getting more advanced, as in Nickel coated brass/copper nozzles (e.g. Bondtech CHT® nozzles) the availability for Volcano hot ends seem to lag behind...
A Volcano heat break adapter/nozzle extender has been spotted on the online market places to be used together with the shorter E3D V6 nozzles.

There seems to be confusion about the mounting of the adapter.
Either from the top of the heater block:

or, from the bottom:

What is the correct positioning of the adapter considering a hex key insert is in the path of the filament, e.g. effects on retraction performance?

I'm not sure what the intended mounting is, but I would put the hex socket downward towards the nozzle. Especially with a CHT, the opening to the nozzle (3 openings rather) is significantly wider than the normal filament path (usually actually 1.85-2.00 mm), and having the adapter widen just before it should help the filament reach the entire opening smoothly once it's molten and expanded in the space.
Conversely, mounting it with the hex socket pointed upwards creates a point in the melt zone where the path widens then narrows again. Due to the way viscous fluids work, material that gets into this space is very unlikely to merge back with the main flow; it's going to stay there and bake. This could lead to jams or at least increased friction from the molten filament having to pass by carbonized gunk. Even if not, it could leave mismatched color/material filament inside the hotend after a purge, only to have it randomly come out later and ruin your print (or at least make it look ugly).


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Sensor can not read temperature
I have MKS TinyBee board recently purchased. The temperature sensor reading gives either 'Err' or '0'.
I have tried all possible sensors in the Marlin table configuration, but still none of them worked. As well as 3 different sensors.
Is the board faulty or I'm missing a setting?

Did you try plugging the thermistor into the other thermistor ports on the board to see if it will work then?

I tried both ports, still the same

Did you find a way around this problem?

How about something simple... have you check continuity on the wire between the logic board and the sensor?

I get this issue, more or less the same.
In my case, it wont read temperature UNLESS both X and Y steppers are active. If any of those is open, it displays err/0.

Welcome to 3D Printing! If you have a NEW question, please ask it by clicking the Ask Question button. If you have sufficient reputation, you may upvote the question. Alternatively, "star" it as a favorite and you will be notified of any new answers.


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Solution for rewinding badly wound filament
It came up in an answer on another question that some filament comes wound with too much tension, making it deform and fuse when attempting to dry it. Rewinding is a solution, but it's a lot of manual work and difficult to do well. Are there working printable systems for respooling filament - particularly, with a mechanism to guide the filament back and forth across the spindle as it rotates so that it ends up distributed properly. I would search for it by name but I don't actually know what that mechanism is called.

It's called a spool winder (or line winder), works much the same as those used for fishing spools and wire. I haven't made one but seen a few printable ones online.
Thingiverse has a bunch of them (I haven't personally tried any)
This one has a moving guide for the filament which is what I assume you're after.
Spool winder with filament guide.

I dislike the two half gear solution, when a single, special Rack would cut a part ;)

@Trish just showing the OP some 3d print solutions I came across, I couldn't personally imagine 3d printing any of them. Seems overkill for the task

@Kilisi: I wouldn't print something so elaborate, just the filament guide with the right gear ratio for about 30-33 rotations per crossing in one direction. Then I'd mount it on plywood or some stacked bricks and turn it with a drill.

@R..GitHubSTOPHELPINGICE If you go for a power driven assembly, You possibly might want to mount at least some of the transmission gears on bearings to prevent them from getting overheated - or at least put their axles into a bearing solution and tightly affix them to those. Just so you don't overheat and crook the gear's hub

None of the things on thingiverse seem to have any reciprocating guide mechanism.

In my manual attempts to respool PLA filament I soon discovered that the natural curl of the filament worked against me. The filament from the outer layers of the original spool has a larger radius curl than the filament that was originally wound close to the core.  It goes on the new spool in the opposite orientation so the natural curl is not tight enough at the beginning and is too tight toward the end. All in all, with poor layering, breaks and tangles it was frustrating, unmanageable and proved to be a losing proposition.

@allardjd I didn't even try doing it that way for that same reason. we just take the whole thing off and respool. It's a bit of work, but filament is hard to get here. Shorter lengths we don't even respool at all justtake it off and run it through from the coil.

@Kilisi PLA becomes bendable and deformable in the airsteam of a hair drier. That might assist in winning against the curl induced by being hot-spooled the first time, but you need to make sure that the airstream is not too hot to melt the PLA

@Trish I don't have a need to automate it. I have 6 kids all locked down with no school since the year started.


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Printer stops printing at the same spot for every model
The 3D printer I'm using (Creality Ender 3 v2) stops printing at approximately the same height and no matter which model I try to print. When it stops, it does not go to park position or auto home, it just stops and sits on top of the print (getting stuck to it). It just started happening out of the blue, I have printed multiple things before this.

I am using the Creality Ender 3 v2, printing PLA at a temperature of 200 °C with the print bed at 70 °C. The Z-axis of the printer woks just fine manually. I changed the nozzle and I've made sure it is not clogged. The firmware does not need to be updated, and the bed is level.
I do not know what else the reason could be. Would love to hear your thoughts and opinions on why this is happening. Here's an image of what the print looks like:

And this is the g-code info from the little I understand about it

Hi CK, welcome to 3DPrinting.SE! Is this a brand new printer and has this always happened, or did this develop lately and now present in every model? Maybe linking to the G-code file (to e.g. Pastebin.com) could help us help you. Could be a faulty modifier in your start G-code. Which slicer do you use?

@oscar, Hi! This is a pretty new printer. Someone else set it up before me and I've just been printing on it since. We've printed about 3-4 models with no glaring issues, until the printer randomly stopped. I have been using the creality slicer. How can I get the G-code file to you? I have never shared it before

When you slice an object, you can save the file, please post this .gcode file on Pastebin.com for instance.

This could be a truncated gcode file, as a result of a corrupted SD card or trying to save the gcode on a full disk (at least in certain configurations, some slicers fail to report an error on writing to a full disk).

@oscar So, I opened the gcode in a text editor. Copied the text, pasted it on pastebin.com and tried to share it but it says that the code is too big. Sorry if these questions are stupid. I have never done this before. Can I put the code over 2 links on pastebin?

@R.. GitHub I reformatted the SD card and it seems to be working now. Thanx!

@R..GitHubSTOPHELPINGICE Please add an answer on the SD card issue, it seems to have fixed the issue. CKPrintissues, please accept that answer when posted. My own experience with SD cards is that is I save to SD card directly from Cura, the print fails, but if saved to HD first and copied to SD it works...

This behavior can be explained by a truncated gcode file - the printer gets to the end of all that's there of the file, and considers it done. A truncated file can be a symptom of corrupt storage media (corrupt SD card), or trying to save a file to a disk that's full with software that ignores the "disk full" error. At least in certain configurations, some slicers fail to report an error on writing to a full disk; I've had this happen when using Cura from the command line rather than the GUI.
Backing up any important data from the SD card then reformatting it is a good first step to try, and seems to have solved the problem for OP.


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Commercial use? 3D scans of museum artifacts
I run a non-profit designed to expose high school students to 3D printing and entrepreneurship. The concept is based on pop-up shop-style sales of 3D printed trinkets, toys, artifacts, etc.
Can I legally sell models we print from the many open source and publicly available museum collections that are available on the internet? Example - a 3D scan of Rodin's "The Thinker" or the British Museum's publically available .stl of the Rosetta stone.
It is my understanding that these artifacts are in the public domain as they are much older than 1930 though the .stl scans may not be?
Keep in mind I am a fully licensed 501c3 non-profit organization.
Wondering if there are any good places to find fully licensed models that we could sell without having to worry about copyright infringement.

This would probably be a better fit on Law.SE. You could ask about this on the 3D Meta.SE and have one of the moderators migrate the question for you.

The artifacts are old, but the STL files are not. It would depend on the license of the STL file.

I believe that this is still a question about legality and not about having a printing problem, hence my suggestion about asking if this question is valid here on 3D.SE or should be moved to Law.SE.

We've had these questions before, could be they got moved to the Law.SE. This answer may be interesting. So, while the object may not be copyrighted any more (70 years after the death of the artist), the file you want to print may. If you make your own scan, no problem.

FYI: https://www.csmc.uni-hamburg.de/publications/aom/001-en.html

Not all museum pieces are out of copyright!
Let's start with a general primer: an Artwork is out of copyright if it was made by someone that died more than about 70 years ago. For items created by companies a different rule applies.
When the copyright on an artwork lapses, anyone can reproduce it.
However, not all items in museums are out of copyright: Auguste Rodin died in 1917 and thus is free game, but Eva Hesse only died in 1970, so her works will only be out of copyright in 2040 or later!
STLs are all under copyright!
However, the STLs are not the artwork, they are a separate artwork that was made by someone that most likely is very much still alive - or at least are still in the protection period.
To use the STL you thus need to acquire a license from the author of the STL. Most freely available STLs are with a license that is "Non commercial" and bans commercial use, so you need to inquire about a commercial license.

It may be easier to get permission on print artifacts if you have no intention of selling or distributing them; only for museum display.  Otherwise, how does one get access to the STL files in the first place.  Open source can have the stipulation that you can only distribute for free.

Just read the license that comes with the STL. Most I have seen prohibit commercial use without permission.

good places to find fully licensed models that we could sell without having to worry about copyright infringement.

Draw them yourself and there's no issues. Or buy the commercial licenses.


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Prints end after 3 or 4 layers after upgrading stock FW to Marlin 2.0.9.3
Finally upgraded my old stock Marlin Firmware to Marlin 2.0.9.3 (current latest release). I'm using Cura 5.0 as my slicer. Printer is a Folgertech Prusa i3, acrylic. It was working fine but I wanted access to some EEPROM settings that stock didn't have.
Everything seems fine until my prints get to about layer 3 or 4, and then suddenly the print stops, the Z-axis lifts up about 5 mm, and all motors turn off. Cura doesn't show that the print failed or anything and continues to advance the progress bar, but all temperature readings stop updating so I assume the printer has terminated the connection. Aborting the print in Cura does not fix the connection, and I can't jog motors until I unplug the USB and plug it back in. The only change I made is updating firmware, so it must be something there. Any guesses what's happening?

Layer 3 / 4 might be a misdetected thermal runaway, caused by the part cooling fan cooling down the extruder too much and it not being able to restore temperature in time (bad PID?) to prevent triggering that feature.
Try a print without the fan. If that fixes it, do a PID tune or adjust the runaway parameters


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Can you fillet the base of an object without needing supports? Is there a recommended radius?
I am currently adding a fillet to the base of an object (the plane that's touching the bed) and I was curious if the radius of the filet contributed to any mis-prints. I've had luck so far but was wondering if the intensity of the radius had mattered.
I am using the Ender3 Pro.

I may do some test prints and see for myself and provide an answer to share experience .

You can print a fillet without support as support material causes other issues like problems with removing supports and ugly scarring on you print. However, a fillet will cause an overhang when you slice the object

and may result into poor results as well, see e.g. this:

If your design allows it you should better use a chamfer than a fillet for the base of the print object.
A chamfer prints better than a fillet because a fillet creates an overhang (see indicated area on the left part of the image below.

Image from 3DVerkstan
A chamfer, which normally is a 45° straight cut-off, doesn't create an overhang and, as such, prints better. If you still want a fillet, you could start with a chamfer of which you fillet the top, see the right part of the image above.
A chamfer with the height of the first and second layer is generally a good idea to reduce the slightly over “squished” first layer issues that create a lip around the base of the part.

The sag is not just "due to gravity". It would happen equally upside down or in zero gravity, because it's due to not having any surface to press the extruded material against. You only get the desired rectangular cross section of extrusion (e.g. 0.4 mm wide by 0.2 mm thick) when there's a surface to constrain where the material goes. Otherwise you get a roughly circular cross section whose Z dimension is greater than the layer height.

wondering if the intensity of the radius had mattered.

Yes it does if it's an overhang.


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Is it possible to send/receive serial messages from/to Ender 3 mainboards (not USB!)?
I want to connect an Arduino or similar MCU board to an Ender 3 mainboard and make them communicate. I don't want to use USB. Are there any pins on the controller boards to achieve this?
I found in the Marlin G-code reference the M118 (serial print) command, this is ideal for my need, but I don't know to catch its serial messages on the mainboard.

You can solder cables to the RX, TX and GND pins on the mainboard.
There are tutorials on Youtube that describe this.


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What could be the cause of these resin prints looking wonky?
I don't know how to describe it, but when I print on my Phrozen Sonic Mini with this resin, this happens (it's Siraya tech, but it happens with regular resin too). The bottom half, the stuff furthest from the build plate gets wonky looking. The first picture, the print supposed to have a flat bottom, but it bulges out, and it has to be round, but it's not perfectly round. I printed it at a 45° angle, and it used a ton of supports, and 3.5  seconds exposure per layer.

This might be a problem with the structure and orientation of the print - if you print large flat areas in one go, the still malleable resin can get sucked at and deform, the next layer then reinforcing the deformed state and thus creating the odd bulging pattern.
You might want to tilt the printed parts so that the flat areas are printed at some angle and thus reducing the area on which forces are applied on layer change.


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Bulging on distinctive lengths along the X-Axis (on all layers)
I have massive print-quality issues on my Anycubic Vyper.
As you can see on the first, third and fourth image, there is some sort of bulging or shifting happening. The issue seems to be related to the x-Axis.
I took the printer apart and inspected the whole axis. No issues were found. The carriage moves uniformly, until it enters the area where the bulging happens. Then it suddenly has a lot less resistance and it feels as if it "slides" into a small detent. I can't feel any issues on the extrusion though.
I can't feel these "detents" when the belts are properly tightened and I move the carriage by hand. There is no sudden massive resistance or anything.
I have tried all sort of different levels of tightness of the eccentric nut. Ranging from stock (problem was there out of the box) to loose to really tight. The problem stays.
I have also re-oriented the bowden tube, it didn't change anything.
The first major bulge is slightly to the right of the center. Left of it no problems were experienced.
What's the issue and how can I fix it?

Have you held a (straight metal) ruler alongside the aluminum extrusion profile. If you slice the "wall" at a different location on the build plate, where is the bulge then located?

Are the bulges evenly spaced? If so, what is the spacing between their peaks?

Looks like the spacing could be exactly the circumference of the roller wheel. I wonder whether the roller wheel shafts are perpendicular to the X-Axis.

Considering the use of a bounty, you are in dire need of an answer, could you please comment on the comments? Or, possibly add more information since there is almost a week past since the bounty was issued.

(1) The bulging only appears at these two X-axis locations, not periodically along the whole axis. The Extrusion itself doesn't seem to have any irregularities I could measure with a ruler or see with my naked eye looking down the length. BUT the problem appears very precisely at the same location each time.
The Y-position (i.e. the position of the bed) does not matter.
I have resorted to avoid printing in that location to avoid artifacts in the part, which obviously isn't the best solution...

(2) What I will try to do when I have the time is to swap out the carriage wheels and bolts and see if this changes anything.
Thanks for everyone who pitched in, but it seems that this kind of issue is not very common...

Maybe try greasing the wheels. I've had a similar effect on a printer that I hadn't used for years. After reassembling it, the x carriage moved freely except at a few points, which were always at the same position. I had to apply more force to get past these points. I don't know whether that's your problem, but it sounds like. I greased the wheel's axles with a drop of oil at each wheel, and now it's running fine again.

The wheels have closed cage bearings, why oil them? Please explain.

I can only tell you that applying some oil to my wheels' bearings solved this issue for me.


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Flashforge adventurer 3 will not home or calibrate
I had a piece of filament break off in the tube and could not unload it so I removed the extruder and pulled out the piece. Reloaded filament and started to recalibrate. The head went to left and tried to keep going. It made a horrible thumping and would not stop until I turned the unit off. I then tried to home it, same result. Tried to reset to factory settings then home it and same result. Any ideas?

This can happen when the end stop of the X-axis (i.e. the minimum end stop on the left) has moved/bent/broken/un-connected.
Please look into this answer of question Flashforge Adventurer 3 - how to replace X-axis endstop. The X end stop is a module inside the print head, please look if the connector is dislodged or something.


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Marlin 2.0.x bugfix: how do you define a specific driver to be used when driving a specific stepper?
I'm using a TriGorilla 2560 and Marlin bugfix 2.0.x, and two stepper motors that I'm using as two Z-axes.
For some reason, both Z ports, and the E1 port are being driven by the same stepper driver:

The problem is that only one port is actually working well, meanwhile, the other ports (one Z port and E1 port) make the stepper jag as in this YouTube video.
Also, there is a driver that looks like it is not being used by anything:

So I wanted to try to assign that driver, to the E1 port (and a Z port), and see how it goes, if it does fix the issue or not, but the problem is that I have no idea on how to do that on Marlin.
Under the pins section either of TriGorilla and RAMPS, all I can find are the definitions of the ports, so I can swap port usage, but not assign a specific driver to a specific port.
If it helps, here's my Marlin zip.

I guess you are asking to swap drivers, this should be done on microcontroller pin level in the pins_[board_type].h file from Marlin. This has been described in e.g. this answer.
Or, do you mean:
#define Y_DRIVER_TYPE  A4988
#define Z_DRIVER_TYPE  A4988
//#define X2_DRIVER_TYPE A4988
//#define Y2_DRIVER_TYPE A4988
//#define Z2_DRIVER_TYPE A4988
//#define Z3_DRIVER_TYPE A4988
//#define Z4_DRIVER_TYPE A4988
//#define I_DRIVER_TYPE  A4988
//#define J_DRIVER_TYPE  A4988
//#define K_DRIVER_TYPE  A4988
#define E0_DRIVER_TYPE A4988
//#define E1_DRIVER_TYPE A4988
//#define E2_DRIVER_TYPE A4988
//#define E3_DRIVER_TYPE A4988
//#define E4_DRIVER_TYPE A4988
//#define E5_DRIVER_TYPE A4988
//#define E6_DRIVER_TYPE A4988
//#define E7_DRIVER_TYPE A4988

Of the configuration.h file?
The following options are available:
 * Options: A4988, A5984, DRV8825, LV8729, L6470, L6474, POWERSTEP01,
 *          TB6560, TB6600, TMC2100,
 *          TMC2130, TMC2130_STANDALONE, TMC2160, TMC2160_STANDALONE,
 *          TMC2208, TMC2208_STANDALONE, TMC2209, TMC2209_STANDALONE,
 *          TMC26X,  TMC26X_STANDALONE,  TMC2660, TMC2660_STANDALONE,
 *          TMC5130, TMC5130_STANDALONE, TMC5160, TMC5160_STANDALONE
 * :['A4988', 'A5984', 'DRV8825', 'LV8729', 'L6470', 'L6474', 'POWERSTEP01', 'TB6560', 'TB6600', 'TMC2100', 'TMC2130', 'TMC2130_STANDALONE', 'TMC2160', 'TMC2160_STANDALONE', 'TMC2208', 'TMC2208_STANDALONE', 'TMC2209', 'TMC2209_STANDALONE', 'TMC26X', 'TMC26X_STANDALONE', 'TMC2660', 'TMC2660_STANDALONE', 'TMC5130', 'TMC5130_STANDALONE', 'TMC5160', 'TMC5160_STANDALONE']


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When I print with a raft on my 3D printer, the raft will not peel off. What settings can I change to fix this?
I recently bought a Creality Ender 3 V2. I have heard that it is best to use a raft when printing. I have tried to use a raft a few different times using PLA, with different settings each time. When I try to peel the raft off of the print, it will snap around the bottom of the print. Are there any recommended slicer settings or printer tips to help this?

Hello @lil mikey. Your question is lacking detail and as such is hard to answer without knowing a couple of things about your printer setup. Please [edit] and fill in the [placeholders] in the template I added and then remove the leading <!-- and trailing --> afterwards. This will turn it visible and help us help you find the actual problem.

I have heard that it is best to use a raft

Actually, it is not best to use a raft, a raft is an aid that can best be used in special cases, e.g. for filaments that shrink reasonably (PLA is not such a filament).
A raft always caused a rough bottom of your print and is frequently difficult to remove. A raft is an aid for adhesion if your print object geometry or choice of filament requires you to use it, but as far as printing PLA, a raft is generally not needed. You need to spend some time to level the bed properly and dial in the best nozzle to bed distance (the thickness of a sheet of plain printing paper like A4 or US Letter will work fine).
There are usually options available in slicer software to control the distance between the raft and the first layer of the print object. It is also reported that inserting a wait time to solidify/cool the raft is beneficial for creating less strong bonds between the raft and the print object.

Have a look at the distance of your nozzle / leveling of your bed. I experienced difficulties removing my prints when the nozzle is to close to the bed. Furthermore try different bed temperatures when removing the print.

I haven't run into this kind of issue, but I've found some tips that might help.

HAVE SOME PATIENCE
You have waited several hours for the print, but you have to wait a little more until the model is completely cool. After some cooling, the model may come off by itself. As the plastic cools, it hardens, losing the tackiness needed for the layers to adhere.

CLEAN THE PLATFORM
This may not help with current printing, but if your platform is clogged with old adhesive, then it's probably time to clean it out. Future prints may not adhere as firmly. If the print is still stuck, run it under a stream of hot (not boiling) water and carefully use a spatula to remove any adhesive on the surface.
After printing, make sure the platform is clean and inspect the surface of the steel. If there are indentations, turn the glass over and use the smooth side. If both sides show signs of pitting, replace the glass.

PUT IT INTO THE OVEN
There are times when hot water doesn't help if you have a glass or other heat-resistant surface with no plastic or electronics and you can take it off the printer, and put it in the oven. Set the temperature to 100º and then use a spatula to see if you can remove the model. If it does not work, increase the temperature to 120º, leave for five minutes and try again. Raise the temperature until you remove the model.

DO NOT USE CHEAP PLASTIC
In many cases, cheap plastic is a false economy.

MAKE SOME HOLES
By creating several holes in the surface of the print base, you can avoid sticking caused by too much surface contact.

Hope these tips help you :)

Hi and welcome. Could you expand upon tip 5? What size holes? What spacing between the holes? What type of base are you referring to? Does this only apply to the Ender 3? Can this apply to other printers? Would that include a glass plate (seems unlikely, although glass is mentioned in point 3)? Do you have a photo? Also, in point 3, why have you inlcuded the link? It might be considered spam... are you highlighting the magnetic sticker mentioned in the link? In point 3, the temperature has not units, preumably you mean °C? Please [edit] and update your answer to address these points. Thanks.

Rafts fuse with models because the filament gets overheated. To avoid this, keep the temperature in the room between between 23 and 28 °C. Malfunctioning extruder fans, a heater & thermocouple, extruder printed circuit board (PCB), extruder cable, and motherboard can be also to blame.

Ambient temperature shouldn’t drastically affect how the layers bond, that would be more of a hotend temp thing and layer height. The plastic comes out of the hotend so much hotter than the ambient temperature, the bonding happens instantly. It stops being sticky quickly. After that it is a little soft until it cools past the glass temperature (60 C for PLA) and gets hard. The next layer sticks because there is enough heat from the fresh plastic to melt the previous layer a little.


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Every time I print with my Ender 3 V2, I get a bubbly ring around the bottom. How can I fix this?
I have a Creality Ender 3 V2. I have done quite a few prints with it using only PLA. When the prints are done, there is always a bubbly looking ring around the bottom of them. I have tried using rafts, and changing slicer settings to fix this and nothing has worked. Are there any ways I can try to fix this?

Hello @lil mikey. Your question is lacking detail and as such is hard to answer without knowing a couple of things about your printer setup. Please [edit] and fill in the [placeholders] in the template I added and then remove the leading <!-- and trailing --> afterwards. This will turn it visible and help us help you find the actual problem. Also, if you could add a picture of what is happening that would help out a lot as well.

Something is wrong with your bed height, Z axis mechanics, or "automatic bed leveling" if you're using that. During this section of the print, the nozzle is not accurately at the requested distance from the bed, and material is spewing out to the sides where the printer tries to print the next layer too close to the previous one.
Try using the printer controls to manually move the head in small increments around 0.1 or 0.2 mm, and measure that the distance between the bed surface and gantry changes by the expected amount each time you move. I expect you'll find that it doesn't.
We'll probably need further information to track down exactly why it's not happening.


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When printing multiple objects at once, or traveling over gaps in prints, I get a lot of stringing. How can I help this?
I have a Creality Ender 3 V2. I do a fairly good amount of printing with it, using only PLA.I have notice when I am printing between gaps or doing multiple objects at once, I get a lot of stringing. Some of the stringing is extremely thin, and others are thick like it was still printing through the gap. Are there any ways that I can fix this?

You need to calibrate your printer better

Do you have any suggestions on how to calibrate?

run a regular room fan by/on your printer and see if the better airflow helps. I've found an old box fan on low about 5' from my cr10 reduces stringing and lets me print large batches a lot faster.

Stringing can arise in at least four ways:

Retracting the filament by an insufficient length to prevent material from oozing out.

Not retracting the filament at all before some or all travel moves, because of bad options in the slicer.

Having filament that's so moisture-contaminated that boiling of water it's absorbed makes the filament bubble out of the nozzle even when it is properly retracted.

Moving the nozzle over already-printed material in ways that tends to "pull it up" and get it stuck to the nozzle, where it later gets deposited as semi-random strings. This mostly happens as a result of travel without retraction (see above) but the mechanism is different; it's not newly oozed material.

To solve it, ensure that all slicer options that cause retraction to be skipped are disabled. Particularly, under Cura or Cura-derived slicers, "limit support retractions" should be off, and "minimum extrusion distance window" should be set to 0 to ensure multiple retractions in rapid succession aren't skipped. And of course "enable retraction" should be on. Watch during a print to make sure the extruder is turning backwards before every travel move from one part to another.
If you still have stringing, tune the retraction distance with a retraction tower. If it doesn't seem to go away regardless of distance, your filament is probably excessively wet, and you should dry it. If you have a good drying setup, this is probably the first thing you should try, since it doesn't require any manual work just time and it's likely to be the core problem.

One more: travel moves that are too slow, so even with appropriate retraction settings the move takes long enough for some material to ooze, or what would have been minor stringing is now excessive stringing.


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Waterproof/resistent cutouts
I've searched a lot but found nothing.
I am fairly new to 3D printing but I know how to print waterproof cases (choosing the right filament and settings).
What I am wondering is how about I/O (Input/Output) e.g. displays, LEDs, buttons, and connectors (ports).
How can I use these parts and how to seal them, etc.?
What other ways do users usually choose for I/O?

why do you want to seal them? You can't print underwater

Can you tell us more about your application? Waterproof, like weather resistant, or waterproof, it’s going to be literally underwater?

Does this fit your application https://www.instructables.com/3D-Printing-Make-Water-Tight-and-Air-Tight-Contain/

@ChinchillaWafers Thx for asking! I mean water resistent. Imagine e.g.  an Outdoor Soil Moisture Sensor with some buttons.


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Aside from aesthetics, are there any benefits to metal infused 3d printing filament?
I recently ripped a piece off of a nitro RC car I have. Seeing as I cannot find a direct replacement at the moment, I modeled it and it seems easy to 3d print.
My main concern is how heat resistant the replacement will be - this is a combined structural/exhaust heat deflector piece.
I've previously known about 30-40% steel infused PLA, but looking at the reviews/overviews everyone states there is no structural advantage to steel/metal infused PLA.
That being said, are there any benefits at all, aside from styling? Temperature resistance, conductivity, stiffness, toughness?

I don't have data, but it seems unlikely there would be major structural advantages, and likely disadvantages. The only likely advantage I can see is heat transfer rate, and I'm not sure it'd be enough to make a difference. If you have particular heat deflection needs you should probably determine the temperatures (and other harsh conditions) involved and ask a new question about what kind of materials would be suitable and whether you're looking to print something yourself or have it professionally done.

As far as I know, the only mechanical gain from metal-bearing filament is that it is the basis for printing metal parts with a filament printer.
This works similarly to Metal Injection Molding: the part is printed with filament containing as large a percentage as practical of the chosen metal (usually stainless steel, bronze, or copper), with a suitable shrink factor applied to the dimensions; the plastic is then baked out in a vacuum oven, followed by a temperature increase to the sintering temperature of the incorporated metal to fuse the metal particles into a solid part.
This can produce parts with similar levels of accuracy to as-cast investment casting, but in shapes that would not be possible (for instance, hollow spaces that don't connect to the surface of the part) and in materials (stainless steel) that are difficult to cast, never mind investment cast.
Notable here is that in this case, the metal inclusion does nothing for mechanical properties of the part as printed, but rather is the final part; the plastic only serves as a carrier to allow the metal to be delivered by a common 3D printer.

The only advantage is the look (debatable, the copper infused filament I tried just looks like vaguely copper coloured plastic) and weight. It weighs more so if your model has a need for weight it's one way of achieving it, although there are other ways.
Personally I think it's worse than normal filament because it's actually not as strong. If you have 30 percent metal powder, then that means you have 30 percent LESS plastic to fuse together. So while it's fine for non complex parts, it struggles to print many others. So you need to design your model with the filament in mind. This is applicable to wood infused filament as well.
So structurally it's quite a big disadvantage, not an advantage.
Electrically it's not conductive, or at least not enough to be useful, I tried electroplating a model and after 2 hours there's wasn't a trace of it plating.
For an exhaust I wouldn't recommend any PLA. They deform under any sort of heat.


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Stepper motor D shaft to Lego axle adapter
I am working on a prototype and I have a need for a motor shaft to Lego axle adapter for use with a stepper motor.
My overall project entails controlling a stepper motor using C# via USB connection to make very small rotations which will adjust the height of a specimen stage (constructed from Legos) for a stereo microscope.
I need adapters similar to 6mm D shaft to Lego axis adapter Free 3D print model but for 4 mm dia motor D shaft and 5 mm dia motor D shaft
The purpose of the adapter is to allow very small and slow rotations.

I do not want to own the model designs, ideally they can be given away for free (similar to the link above).

I need several of the adapter pieces; 3 of each (4 mm and 5 mm) printed and what would be a fair price for this?

I have no idea what type of material should be used to print these, I think Acrylonitrile Butadiene Styrene (ABS) would do.

This seems like a nice exercise to practise beginner CAD skills in.
b) 50 / hour of design time, 5 / hour of print time is what I usually use.
c) ABS, ASA, HIPS or, if possible, Nylon
d) Artillery Hornet, though purchasing suggestions are out of scope for this SE.

Hi Gary, welcome to 3DPrinting.SE! Please note that printer recommendation is out of scope, I've removed the request from the question. Feel free to drop by in our public chat channel.

OpenSCAD would be well suited for creating something made up of relatively simple shapes, where different dimensions are needed for some parts of the shapes - like the diameters and offsets of your stepper motor shafts.
A solution in OpenSCAD could look something like this:
outer_diameter = 8.5;   //Outer diameter of the adapter
stepper_length = 12;    //Length of the stepper shaft
stepper_diameter = 4;   //Diameter of the stepper shaft
stepper_d_offset = 1.6; //Offset from the center of the shaft to the plane of the D

//4mm shaft: d = 4, offset = 1.6
//5mm shaft: d = 5, offset = 2
//6mm shaft: d = 6, offset = 2.5

thickness_mid = 2;      //Thickness of the massive section between stepper and lego shafts

lego_length = 10;           //Length of the lego shaft
lego_diameter = 4.9;        //Outer diameter of the lego shaft
lego_internal_width = 1.9;    //Width of the slots for the shaft
lego_corner_radius = 0.5;

cutout_size = lego_diameter;
cutout_translate = cutout_size / 2 + lego_internal_width / 2;
$fn = 128;               //Accuracy / resolution of circles
eps = 0.01;

module fillet_square(width, radius) {
    translate([radius - width / 2, radius - width / 2, 0])
        minkowski() {
            square(width - 2 * radius);
            circle(radius);
        }
}
color(0,0.5)
union(){
    linear_extrude(height = stepper_length + eps) {
        difference() {
            circle(d = outer_diameter);
            difference() {
                circle(d = stepper_diameter);
                translate([0, stepper_d_offset + stepper_diameter / 2, 0]) {
                    square(size = stepper_diameter, center = true);
                }
            }
        }
    }
    translate([0, 0, stepper_length]) {
        linear_extrude(height = thickness_mid) {
            circle(d = outer_diameter);
        }
    }
    translate([0, 0, stepper_length + thickness_mid - eps]) {
        linear_extrude(height = lego_length + eps) {
            difference() {
                circle(d = outer_diameter);
                difference() {
                    circle(d = lego_diameter);
                    translate([cutout_translate, cutout_translate, 0]) {
                        fillet_square(cutout_size, lego_corner_radius);
                    }
                    translate([cutout_translate, -cutout_translate, 0]) {
                        fillet_square(cutout_size, lego_corner_radius);
                    }
                    translate([-cutout_translate, cutout_translate, 0]) {
                        fillet_square(cutout_size, lego_corner_radius);
                    }
                    translate([-cutout_translate, -cutout_translate, 0]) {
                        fillet_square(cutout_size, lego_corner_radius);
                    }
                }
            }
        }
    }
}

You can then export your .stl file (or any other format) for 3D-printing from OpenSCAD.

Great answer, I'd consider a larger outer_diameter for increasing the load bearing capacity (torque). Maybe mentioning that you shouldn't print this upright might be useful.

Thanks for the solution.  Installed OpenSCAD and pasted in your code the part rendered without issue!


text:
Filament not being extruded
I'm pretty new to 3D printing, got my printer about 5 days ago and spent most of my time with it.
First off, it is an Ender 3 Pro with everything stock, haven't made any upgrades except I run it with OctoPrint from a Raspberry Pi Zero but I have determined that's not the source of the problem as it's well within 80 % idle on its CPU.
The issue I'm experiencing is that the extruder starts slipping at some point along the print. It's not the clicky type of slipping that appears to be the common issue but rather it's just spinning and grinding on the filament which is remaining stationary. When this happens the printer continues on about its business as it's unaware that filament is not coming out. I move the Z-axis up, squeeze the extruder lever and try to push on the filament which is not budging, which made me think I had a clogged nozzle. I was surprised as it's a brand new printer but the internet says that nozzles clog up so I disassembled and cleaned it just to find that it happens again on my very next print. I noticed that when I pull or push on the filament by hand while squeezing the extruder lever - relieving pressure from the gear, it is quite hard to do so, even partly impossible as my fingers start to slip, I have to squeeze extremely hard or use pliers. I pulled the filament out using quite a bit of force, then snapped off the piece that was already in the tubing and inserted fresh filament which slid very easily through the white tubing to the hot end and when reaching it by pushing very gently I start to see filament coming out as opposed to pushing really hard and barely anything coming out previously. If I do that and return the Z-axis to its position then resume the print it continues until that happens again.
My bed is leveled as best as I can, I downloaded the bed leveling G-codes that help a lot to achieve good adhesion, my prints look pretty much perfect, smooth lines very pleasing to the look and touch, until what I mentioned above happens.
I don't understand what could be the reason that my filament would just bind up like that and snipping it off and inserting a new piece there's no sign of the issue whatsoever.
Notes for what it's worth:

I'm using cheap black PLA 1.75 mm
Hotend temperature 200 °C
Bed temperature 60 °C
Printing speed 50 mm/s
The extruder pulley (white wheel with the bearing) bolt is not tightened to the end as recommended on the internet
The spring bolt on the extruder is not tightened also, as I see there are marks on the filament that went past the extruder wheel, anyway I tried tightening it for the sake of it and it didn't help
My extruder arm is not cracked
The gear (brass wheel) doesn't seem to be damaged

Have you unscrewed the nozzle and tried pushing filament manually through the Bowden to see if there is a lot of friction in the system itself?

@0scar yes I tried, it didn't seem to have any issues going through, although there are some scratches on the outside of the tube where it meets the (i don't know what it's called) on the top but I assume that it's fine on the inside.

This is probably the filament. I've had the exact same issue on my Ender 3 Pro and solved it by baking the filament.
I suggest you try with another filament just to make sure. Or bake a length of the filament for a couple of hours at 50 degrees and try again.
The other possibility is that the filament is not consistent in diameter.

Well it's an Acccreate 1.75 PLA filament and reviews online seem to be only positive. I'll try getting anothrr brand but what would be a recommended one? Is sunhokey any better?

I've found it's not so much the brand as whether the filament has absorbed enough moisture to create the problem. Mine came seafreight which took months and were mostly rubbish by the time they arrived. The same filament brand that came airfreight printed fine.

I experienced similar problems when I changed to other filament. The solution was to open my enclosure as the inside temperature was too hot and the filament got too soft for extraction.
Moreover have a look at the gear wheels position and maybe adjust the height a bit. At one time my wheel screws got loosened and the wheel was sitting too low resulting in irregular skipping.

Ender 3 Pro doesn't have an enclosure

also on my 3 pro the gear height can not be adjusted

I had a similar issue with my Ender 3, and it was a combination of things. First, the hot end (inside) was clogged. I took the entire thing apart, heated it up, and cleaned it out. There is also a method called a cold pull, I did that a few times.
I then also replaced the Bowden tube because it had gunk in it and cause the filament to not flow as it needed.
After doing those two things, the printer began extruding.
One thing I noticed is that those little brass wheels get worn down by the filament really quickly if the stuff isn't moving through the Bowden tube. The PLA just grinds the gear down. You should probably replace that wheel/roller or just get the all-metal extruder like one from Amazon. I think this is worth the $10.
Also, you may suffer from under extrusion after doing this and you should probably calibrate your extruder.
It's not hard.
Doing these things got my Ender back up and running.

I think I figured mine was also a combination of a few things but not necessarily the ones you have mentioned. I put a desk fan right next to the printer and after doing a few 8h+ prints I think it's safe to assume that the 40x10 fan is just not up to the task at 27+ C ambient. We'll see how it goes when it gets colder after a few months without the fan.


text:
Moving bed Y-axis belt keeps skipping after replacement
I replaced my belt that had snapped and tightened it with the tension adjuster. Now, either the tension is too tight to allow the Y-axis belt motors to move the bed, or otherwise, the bed skips at some point during the print at least once, offsetting the entire print and ruining it.
Perhaps I could increase the power to the motor, but how would I do that, and also is that smart judging by the factory settings power limit? I don't want to overpower the motor, the belt is pretty much identical to the one before it so I would imagine it should be the same performance.

Klipper + FluiddPI
Raspberry Pi 3+
Anycubic Mega X

Here is a link to some videos of the belt being moved manually. I can see it skipping on the belt here at various tensions. does this show anything particularly telling? I am almost certain the two belts are the same, but maybe I'm wrong..
Belt tight (too tight to allow the Y-axis belt motors to move the bed):

Belt loose (the bed skips at some point during the print):

If the old belt was so tight it snapped, I would be worried the motor bearings are completely shot and the motor shaft binding, or that the mounting brackets are bent. A belt has to be extremely overtightened before it will snap, so much that it would do other damage.

when i tighten too much it it doesnt move, when i loosen it it still skips but less often, until  i loosen to a point where its just far too loose to do anything.
I mightve broken it when trying to move te bed and adding too much pressure while the motors were engaged, im not sure because i noticed it broke so after the fact. .
How would I determine any of the potentialities you listed above?

Remove the belt and rotate the shaft by hand, not powering the machine, preferably dislodge the cable, see if it rotates normally (compare with another stepper). A replacement stepper (you need type A of the Anycubic replacement steppers) costs about 15 Euro, I'd order a spare and see what that does, not expensive and always handy.

just did that, that's what in the video actually, i was moving by hand. didn't see any abnormalities but it did look like some weird disturbance was happening in the cord, not sure if its the stepper motor or belt design. The belt as far as I can tell is identical to the original...


text:
Why is it more common to move the extruder on the Z-axis than the print bed, in consumer FDM printers?
Why is it more common for consumer level FDM printers to move the extruder on the Z-axis (For example, the Ender 3) while the bed remains at a fixed height, than to have a bed that moves up and down on the Z-axis?

if the nozzle is crooked it's no big deal. if the bed is crooked, it's a very big deal.

The reason is economics, building cheap printers for the masses requires the use of as less material as possible; this keeps the price down.
A bed that moves up and down requires a sturdy construction and usually more and more expensive materials.
If you look at the Prusa i3 style printer, the bed moves in Y direction while the X-Z is a single plane perpendicular to the Y-axis. This allowed printer designs to have a single upright frame made from acrylic (not the best solution, but cheap) or steel plate (expensive due to the cutout and waste material) or aluminum profiles (value for money solution). If you need the bed to go up and down, you need to constrain the X-Y plane high above the build plate (e.g. Ultimaker printers, Hypercube, etc.); this requires a stiff frame and hence more material.

Do note that e.g. the Voron 2.4 although a boxed up printer, has a fixed bed and a moving X-Y plane. This requires even more materials and is even more expensive.

Building the printer upside down avoids a big part of this constraint. See for example the Positron V3.

@R..GitHubSTOPHELPINGICE As seller of such a concept I would be concerned on supporting my community with prints not sticking to the build plate... ;-)  (Thanks for the reference though!) Furthermore this concept uses linear rails which are very expensive compared to aluminum profiles, plate steel or acrylic, especially the quality ones.

FWIW I think the back-and-forth motion of a bed slinger is probably more of a problem for adhesion than gravity.


text:
Creality Ender 6 does not boot beyond the boot screen
My Creality Ender 6 has stopped moving beyond the boot screen.
It kind of happened suddenly. Another thing is that I have a red light on the motherboard at the D2 location that is turned on continuously after I turn on the printer. The screen is stuck on boot.
What happened before the problem:
The distance between the nozzle and the bed was low, so there was a lot of accumulation of polymer. I had to clean much of it manually after I saw it had built up significantly. It had accumulated so much that it was even touching the internal fan, and got accumulated on some of the wirings on the printhead as well. I broke a portion of the fan's fin in cleaning out the then solidified polymer. After I turned the printer off and turned it back on once the cleaning was done, it got stuck on the boot screen and has not moved beyond that point despite my trying different things.
Can anyone advise what could be the potential sources of the problem and how these could be resolved?

If you could [edit] in more details of what happened prior to the printer no longer booting beyond the boot screen, this would help in diagnosing a problem.

Have you tried to unplug (while not powered!) all connections except for the display and power lines and start/boot the printer?

@agarza, the distance between the nozzle and the bed was low, so there was a lot of accumulation of polymer. I had to clean much of it manually after I saw it had built up significantly. It had accumulated so much that it was even touching the internal fan, and got accumulated on some of the wirings on the printhead as well. I broke a portion of the fan's fin in cleaning out the then solidified polymer. After I turned the printer off and turned it back on once the cleaning was done, it got stuck on the boot screen and has not moved beyond that point despite my trying different things.

@Oscar, I have.


text:
Meaning of light prompts on Ender 6 motherboard
What are the meanings of the red, green, and blue light prompts on the Ender 6 motherboard? My Ender 6 is stuck at the boot screen. I followed the instructions provided in the "Creality After-Sale" videos on YouTube and took apart the base of the printer to look if any wiring was loose.
I found that the red light was continuously on at the D2 position on the motherboard. Creality's video showed the light on this location of the motherboard to be blue. I also checked on the internet and it appears some users also have a green light. Users also report the light blinks but in my case, it remains red throughout.
I am wondering if this indicates what is wrong with my printer and why it is stuck on the boot screen.

A good clear photo of the LEDs might help (although I've included a screenshot from the manual, in my non-answer below). I believe that there is also an LED at D4 - are there any others? Also, please [edit] your question and provide a link to the Creality video to which you refer which shows the blue light. Are you sure that the blue and green lights are for (a) the same printer/motherboard, and (b) the same LED location (and not a different LED, such as D4)?

Did you ever get a solution to this problem? If so, please post an answer, as it could be useful to others.

@Greenonline, I did. The motherboard was fried. Changing it resolved the problem.

Ah, good. If you could post a simple answer and mark it as the accepted answer that would be great (just to remove the question from the unanswered queue). Thanks. Did you ever find out the meanings of the LED colours?

I found out that the motherboard had gotten damaged and the green light indication had to do with showcasing this. The problem was resolved when I bought a new motherboard online and replaced the damaged motherboard with the new one. The printer works fine now.

This is a bit of a non-answer, and I've posted it only because:

it was too long for a comment, and;
to provide some info in order to save people having to pointlessly search for data that isn't actually available in the manual.

Apparently you aren't the only person with similar issues relating to understanding the meaning of the LEDs - Creality appear to be not very good at providing info about these LEDs... see this page on Reddit, Ender 6 motherboard lights.
The user guide (on manualshelf.com) doesn't mention the LEDs at all. I flicked through all of it and the most useful page was page 29 which showed the motherboard but (again) there was no mention of the LEDs:

For reference, the LEDs at located thusly:

D2 is on the left hand side of the board to the left of the heatsink.
D4 is on the right hand side, just behind the USB socket

FWIW, D2 seems to be red when powered on, as mentioned in this post and this post on My Creality Ender-6 is stuck at the boot screen with the white status bar.

You may need to issue a service request... if you do so, and get a response, please post an answer as it would probably be of benefit to others.


text:
Ender 3 Thermal Runaway Error when booting up
I am trying to fix my Ender 3 printer at work. Someone else had it before me and added a direct drive extruder, auto bed leveling, and changed the firmware. He claimed it worked fine, however when I started a print the nozzle was clogged beyond belief so it would not print.
I changed nozzles and had to clean up the heating block a little bit. Once I reassembled the printer and booted it up it shows the error message of Thermal Runaway for extruder 1 and tells me to reset it. I tried powering it off and back on to "reset" it but that did nothing. Within about 10 seconds of turning the printer on the error message shows up and it starts beeping obnoxiously.
Is this caused by something wrong with the thermistor? Everything I have read so far says to check for a faulty thermistor and see if the room temperature reading is 0 °C. However, I cannot do that because it gives the error instantly and will not leave that screen.

Why not return it?

I can't return it. The person who was formerly in charge of it got pulled off the project because he was not getting enough done, so now I inherited it and have to get it running properly again. We have owned the printer for quite a while. It worked great when it showed up in it's un-modified form. Now that he added all of these extra things we cannot figure out how to get it to work, and getting rid of the thermal runaway code seems to be the first step in getting it working again'

Why not return it to stock condition? Perhaps just flashing the firmware might solve the problem

Will try that and report back. My boss is worried that he has it so messed up we can't return it. Not sure we have to parts to revert it back to bowden extruder though. Does direct drive change the firmware required? or can direct drive run on the original firmware? It is just the stock extruder mounted over the hotend.

For the price of an Ender 3 I'd be tempted to write it off and keep it for parts and buy a new one. Troubleshooting may cost more than the replacement.

No offense, but for a corporate environment you might better invest in a higher quality printer. If you have to fiddle with the printer for a few days, you'd loose so much in labour costs that it is easily justified to buy a more expensive printer.

Kilisi and oscar, I asked about that, they said since it is not for production and just for prototyping they don't want to spend more money right now on a 3D printer. We have other printers, this one is just the one that is currently broke.

I've found a single reference of the same issue you are experiencing. That Ender 3 also showed the thermal runaway error on startup.
This was caused by a hotend thermistor that was shorted out, replacing the thermistor solved the issue.
Quoting the reference, context:

I installed a new Micro-Swiss hot end.Did a few prints with it, works great!When I wanted to do another one, the printer made a loud beeping noise, and gave a Thermal Runaway at E1 error at startup.

Solution:

For people stumbling across this in the future, my issue was resolved by a shorted thermistor. After changing it to another one, the printer worked fine and gives a temp readout.

Thanks, got a new thermistor on the way, will report back wit how it turns out.

Same issue, It seems over tightening the thermistor can cause it to short. Re adjusting the thermistor seems to fix the issue issue in my case. A new one is probably worth picking up though. this doesn't inspire confidence


text:
Connecting controller fan on RAMPS 1.4 for Marlin
I have radial fan with 2 pins connector and always kept it connected to GND/5V pins (marked J5 at the left bottom on pinout image for my controller board).
I've stumbled upon the USE_CONTROLLER_FAN feature of Marlin which allows setting some pin to be used for PWM-controlling a control board fan. I think SERVO0_PIN should do fine (D11 at the bottom center on the pinout image), but I'm not sure how to connect it.

Should I split connector and use GND + D11 pins?
Or should I use some proper PWM fan for that (which are always 4pin and then how would one connect THAT to those pins?)
Is it safe to run a fan directly from board pins or should I resort to using either unused MOSFET outputs (e.g. FAN MOSFET pin marked as D9 on the left)?
Should I use dedicated MOSFET board to drive that fan using that SERVO0_PIN?

Servo pins are PWM pins, so yes D11 can be used, but not directly connected to the fan as the pins only allow a very low current. You'll need a MOSFET to drive the fan. You don't need 4-pin fans, 2-pin fans will suffice.


text:
Printing half size after board replacement
I recently burnt out one of the MOSFETS on my RAMPS 1.4 board on my Sintron Kossel clone so have upgraded it to a RAMPS 1.6.
Now my printer seems to only print 50 % of the intended size.
After the machine homes it only comes down about 50 % of the distance and so starts printing in mid air.
I thought it might have been the driver steps? The DRV 8825 drivers are 32 steps instead of 16. I changed this value in the firmware but it didn't make any difference.
Any suggestions?

What did you actually change than? You should adjust the steps per mm. If you go from 16 microsteps to 32 microsteps you need to send more steps (twice) to achieve the same distance to travel.

Data from Firmware is not written into EEPROM on its own after updating your firmware. You need to send a M502 to "seed" the firmware numbers as that is restoring the "default" settings in it. If you are unsure what is currently the EEPROM setting, use M503 first.

If you changed you stepper drivers here's a list to check:

Microstepping Jumpers
In Marlin Configuration.h:

X_DRIVER_TYPE, Y_DRIVER_TYPE, Z_DRIVER_TYPE and
E0_DRIVER_TYPE
DEFAULT_AXIS_STEPS_PER_UNIT
INVERT_X_DIR, INVERT_Y_DIR, INVERT_Z_DIR and INVERT_E0_DIR

In Marlin Configuration_adv.h:

MINIMUM_STEPPER_POST_DIR_DELAY, MINIMUM_STEPPER_PRE_DIR_DELAY, MINIMUM_STEPPER_PULSE, MAXIMUM_STEPPER_RATE
Other driver-specific constants

EEPROM settings stored on the control board (use M503 to read current settings).

many thanks for the advice. will check those things out.cheers scott


text:
Is there a way to make my 3D prints airtight?
I printed a G1/8 thread in PLA where I can connect a compressor to have a small pressure container. Even though all measurements are correct and it screws in fine, it still leaks air.
Is there a way to make 3D prints airtight?

Did you try Teflon tape around the threads?

In theory, yes you can without any additional materials. But it requires a very high level of perfection for your 3D printer's output.
"Gaps between layers" are not the issue. There is no "gap" between the extrusion at layer N and an identical-path extrusion at layer N+1 if layer N+1 is extruded correctly and remelts the surface of layer N sufficiently to bond everywhere. There are grooves between layers from the extrusions not having perfectly rectangular cross-section and rather slighty rounded edges, but these are not "gaps".
Where gaps do come in to play is from inconsistent extrusion. If at any point the printer fails to resume extrusion where it's supposed to, or extrudes slightly less material than it's supposed to, there's a possibility that the complete remelt/bonding described above does not happen. It's also possible that grooves turn into gaps under high pressure, by providing a surface where the pressure can act like a wedge to separate weakly-bonded layers.
Also involved here are issues with the filament quality. If the filament contains air pockets or has absorbed moisture, there will be tiny bubbles bursting in the extrusions, making a potential path for air to pass through.
I have not succeeded in producing an air-tight container, especially not at high pressure, but I have made test containers for a vacuum that take several minutes to return to ambient atmospheric pressure after the pump is removed. This was using PLA with a non-high-temperature-capable hotend. I'm planning on revisiting this at some point with the temperature cranked way up (now with all-metal) with PLA and other materials to see if there's any practical viability to the theoretical possibility of getting it right.
Short of that, iblue's answer to use an airtight coating is a great option if you can deal with the dimensional changes or compensate for them in designing your parts.

Have you tried it? I pressurized my print and put it into water. It bubbles all over the surface. If there are no gaps between the layers, where does the air come from? Also, the dimensional changes seem to be small. I have not measured it, but the threads work as before.

@iblue: My answer states what I have and haven't tried as well as several plausible explanations for where gaps exist.

Curious if adding more wall lines improves this.

@JoelCoehoorn: I used a large number of walls such that the part was entirely walls (no infill area) and Cura 5 which uses variable wall line widths to avoid leaving any gaps.

I have to interject a word of caution here. 3D printed materials don't have a lot of tensile strength and layer to layer adhesion is the Achilles heel. If pressurizing a 3D printed vessel it would be prudent to hydro test to at least 125% of the intended working pressure.

Yes.
The issue is, that there are small gaps between the layers. But you can coat the print in an airtight material. While epoxy and similar materials work very well, they are somewhat too viscous and take a long time to cure.
My special recipe for coating PLA prints with a fast-curing airtight thin layer is:

Dissolve 1 g Paraloid B-72 in 20 ml acetone.
Dip or otherwise evenly coat the print and dry at room temperature for 10-20 minutes.

Most PLA has additives that acetone attacks. How do you deal with that when performing a long dip? Do you get special additive-free PLA?

I use AmazonBasics PLA and dip for about 10 seconds. That's sufficient, because the fluid is very low viscosity. I did not notice any issues.


text:
Are thick layer lines easier to sand and fill than thin layer lines for low detail objects
When printing an object on an FDM printer, is it easier to sand and fill thick layer lines than thin layer lines for low detail objects such as small plates for cosplay armor (Under 6 inches in size per print), in order to get a good finish?
PLA, Ender 5.

No. The outside of the layer has a round cross section, so the higher the layer, the larger the semi circle cross section and the deeper the valley is between layers.
Fine layers take forever to print large objects though, so for making costume parts I would go max layer height. To get a good painted finish you don’t need to sand to the bottom of the valleys though. Sand the high spots so about 50% of the layer edge is flat, then use automotive “high build primer”. Paint it on thick and don’t worry about runs. The high build makes the paint fill in the valleys. Sand it again, down to when it’s smooth, or when you’ve exposed the plastic of the high parts of the layers. Can do it again if it’s still bumpy. Then regular primer (recommend same brand/line as the high build for chemical compatibility), light sand, and paint. If you sand with fine grit between layers of paint you can get a very impressive finish.
The key ingredient for nice paint is the high build primer, it is a great companion for FDM printers. They generally have it at the auto parts store, rather than the hardware store.

also, automotive putty is your friend. I had good results with acrylic putty for woodworks - it is thick and can fill deep creases and rough edges and undersides, while can be easily watered down, and sands really well when dried out.

Already got me a tin.


text:
Anet ET4 - Thermal Runaway immediately after Boot
Most of the time I print PLA with my Anet ET4 (with Marlin firmware). Yesterday I again wanted to print with ABS and preheated nozzle (245 °C) and bed (80 °C). Everything worked fine for a few minutes, but suddenly I got an error:

Thermal Runaway: Bed
Printer Halted
Please Reset

I reset the printer and after booting (Anet logo was shown), this thermal runaway error immediately popped up again. I then removed the NTC thermistors of the bed and also of the print head with no improvements.
I read that in this case, I should check the cables and the thermistors - but they are all good, the same problem despite replacing the cable.
I also do not understand why this error occurs immediately after booting.
Maybe could it be that a MOSFET on the board is defective?
I hope someone can help me with this problem.

How did you test the bed thermistor? From this description I would guess that the bed thermistor reports an invalid temperature.

It has been tested with a multi meter (normal resistance measurement).
I even do not get into the home menu because the error message appears immediately after switching on. Tried also other 100kOhm NTC thermistors and also a print bed of a Anet A8 with no improvements.
With my little knowledge in 3D printing I can't imagine why the mainboard of the printer could be broken!? And before I buy a new mainboard I will check all other error sources to be on the save side.
I appreciate any advice.

The issue might be between the connector for the bed sensor and the pins of the processor. You could check the PCB for bad solder joints. There are probably some resistors between the connector and the processor.  The voltage measured at the processor pin should be above 0V and below 5V. Probably rather close to 0V so more like 1V or less.
Electronics can break, this is not 3d printing specific. But your printer is neither open source software nor open hardware. That makes i hard to give specific advice.

OK, I will try it.
Should this error also occur if no sensors (thermistors) are connected? Because if I disconnect the printbed and also the hotend, I still get this thermal runaway bed error immediately after turning on the printer. Is this normal for a working motherboard too?

yes with the thermistor not connected the error must occur! One of the failure modes of the thermistor is that the cable breaks and that looks for the electronics exactly the same as no thermistor connected.