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How can microswitch-based automatic bed leveling probes be possibly reliable and accurate?
I just discovered automatic bed leveling (ABL) probes that only use a microswitch.
For example, the FreeABL as shown below:

Source: Thingiverse.com
Or, the magnet mounted KlackEnder as shown below:

Source: Thingiverse.com
Both use the simple concept of probing the bed using a microswitch instead of an optical or retractable touching probe, such as the popular BLTouch. However, since no measurement other than touch can be made, how reliable and accurate are such methods? Did someone ever run a Probe Repeatability Test (M48) for such microswitch based automatic bed leveling probes, or have experience regarding its reliability?
For reference, a 10-probe M48-test using my CRTouch results in a deviation of 0.000750.

My printer used these for Z homing before I added a BLTouch. Anecdotally, the first layer thickness reproducibility was not great, although I never did any numerical tests. Ironically, the little lever arm actually increases the inaccuracy. It magnifies the motion of the actual clicky button, so it magnifies its trigger point tolerance as well. Again, no data, so just a comment and no answer, sorry.

I have come across this on the internet, just search and you will find. The microswitches are indee not very reproducible.

@Fritz: You're supposed to remove the metal lever arm when using them, for exactly the reason you mentioned.

@R..GitHubSTOPHELPINGICE Yeah, that's what I thought, but then (A) why are they there in the first place and (B) why are there so many printers out there with the lever arm in place? Granted, my printer was a cheap chinse i3 clone... (also, it's in the photo in the question above :D)

@Fritz: For homing an axis where you don't care about perfect repeatability, the lever arm doesn't hurt anything and I suspect it saves wear on the actual microswitch button.

@R..GitHubSTOPHELPINGICE Well, you are right, if you have automatic bed leveling that compensates for homing inconsistencies. But I've seen printers without ABL that use such a lever microswitch for homing, and the problems that causes, namely inconsistent first layers. And in the photo above, the switch with lever is used for automatic bed leveling, which is an even larger concern.

@Fritz: I was talking about X/Y homing where you don't care about reproducibility unless you're trying to resume a failed print. For Z, having the lever there is indeed dumb unless you're re-probing anyway (then why not just use probe-as-Z-endstop?) and just want to get the Z homing 'close' (maybe to use with a quickdraw that needs Z close to pick up a probe from a dock?)

I use them both for my Ender 3 home-against-bed and for my delta-calibration probe, and they work reasonably well. Of course, as noted in a comment by Fritz, you should remove the metal lever arm, as that amplifies any error, as well as introducing its own non-reproducibility through arm stiffness that may vary with temperature.
I forget the actual spread of values I get probing my delta, but my Klipper probe configuration has samples_tolerance set to 0.015 mm, meaning that, when it probes each point 5 times, it will start over if it gets measurements that differ by more than that amount, and normally it does not restart. However, with it previously set lower (probably 0.005 mm but I don't remember for sure), I did on occasion hit instances of it repeatedly failing. So, in my usage, it was repeatable with an error margin of something greater than 5 microns but less than 15. I don't think that's too bad.
The particular switch/PCB I use was a cheap generic "Ender 3 endstop switch replacement" off Amazon.


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Is it required to use a data-only USB cable to keep the LCD screen off, when a 3D printer has no other power provided?
I've noticed before that when I use a standard USB-cable to connect my Creality Ender 3 V2 printer using its USB port to a Raspberry Pi 4 and powered off the printer, that the LCD screen of the printer stays turned on. Even when the power cable is removed from the power supply of the printer, conclusion: the LCD screen draws power from the Pi over USB.
Although that seems like a horrible design for the v4.2.2 Creality board in my opinion I bought a simple PortaPow Power Blocker USB connector as shown below:

I could imagine there are other solutions to this but my question is: Is cutting the power over USB indeed the right approach? Is it common to do that for this type of printer and is it indeed the result of bad design by Creality?

If your question is whether a data-only USB cable is required in order to keep the LCD screen off until 12 V power is applied, then the answer is yes. However, then realize that you won't be able to flash new firmware onto your 3D printer board nor upload new 3D prints until 12 V power is applied again. Every time you want to upload a new 3D print to your printer, you'll have to turn on the heavy power supply attached to the wall. In the long run, this may use more energy, if for example, you forget to turn off your printer.
Ultimately, I think that I agree with you though, that this is a questionable design choice. On the other hand, 3D printers emit a ton of microplastic, and you probably shouldn't be using them in an environment where the light from an LCD screen would bother you. (Not in a bedroom, for example.)
On most 3D printer boards, everything 5 V and below is powered by the USB cable, or the 12 V power supply. If one is active, they will be powered. If you had relays attached to 5 V pins, for example, they would be "on" when the USB cable is attached, just like the LCD screen, and just like all the "thinking" parts of the 3D printer board. The "muscle" like the motors and heaters rely on 12 V and obviously aren't powered by USB. Everything 5 V and below is flexible in that way, it can be powered by USB or 12 V, but 12 V can only be powered by 12 V. (This is only within the context of 3D printer boards... there are other things called boost converters that can convert 5 V to 12 V, but there is not enough power from USB to do that to power a 3D printer.)
Some boards like the SKR mini v1.1 have a movable jumper that you can use to choose whether things like the LCD screen are powered by the 5 V USB input or the buck converter attached to the 12 V power supply. (However, this is a really cheap board.) With this board, you wouldn't need a data-only USB cable. I don't recommend this board, however.
It might also be possible to turn off the power provided to all USB ports using software on the Raspberry Pi.
You don't need a special adapter like that, either. You can use a small and removable piece of masking/duct tape, and some tweezers, to turn any USB cable into a data-only USB cable.

I don't understand the inability to flash firmware actually. Nor is it about the light of the screen. The brightness can be reduced to 0, effectively turning the screen off. My main issue is that the screen stays on when the printer is off, that just seems wrong. Potentially drawing too much power from the Pi too.

If the printer’s main switch is set to is off, and the usb cable is data only (not providing power), there will be no power to flash firmware or upload 3d prints to the board.

The LCD draws a negligible amount of power

“Flashing firmware” means updating the microcontroller code on your 3D printer to let it to new things (like maybe add an activatable heated chamber or an exhaust fan)

I understand what flashing is but I don't see how flashing is relevant to this question at all . By 'potentially drawing too much power' I meant we don't know what else draws power on the main board, the USB cable is connected to the board, which powers the LCD. I think the use case of USB cable should always be data only in the sense of 3D printers.

… It’s relevant because if you use a data only usb cable, you won’t be able to flash without turning on the heavy power supply. Also, The LCD screen, like the USB protocol, uses a negligible amount of power (about 0.002kwh or 0.0002 dollars per month)

Please read my answer about the 12V powering the LCD when it is on. It’s not always powered by USB

source: Stack Exchange

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

sort: votes


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What defines the 'straightness' of linear rods and how to measure it?
A few closely related questions about the straightness of linear rods. The 'straightness' of linear rods is vital for a 3D printer to function correctly and prevent things like Z-Banding or Z-Wobble. So, how do we measure the 'straightness' of linear rods? What measurement method or metric can be used?
I can imagine using some reference material (a piece of wood or a table), but then again, how would we know the reference material is perfectly straight? Lastly, how straight does it even have to be? What's a standard or acceptable range they should be in, and is there a standard that defines, classifies, and indicates this?

It is hard to het a very straight object to verify your rods against. A regular household measure is to use a metal ruler on its side; not everybody has access to a perfectly flat slab of granite/steel as I had at my previous employer (e.g. used for mounting optics).

A common metric for straightness of shafts in industrial equipment is Total Indicated Runout (TIR). The shaft is placed in V-blocks or ball bearing rollers at its bearing journals. Runout is checked at various positions along its length with a dial indicator as the shaft is rotated.
This method could be easily applied to guide rods supported at the same axial locations where they are held in the printer.

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


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Is it safe to use 230 V AC, 10 A relay shield to turn my Prusa MK3S+ on/off using OctoPrint?
Prusa says the MK3S+ draws up to 120 W. So let's say 150 W of inrush current.
$$150 W \div 230 V ≈ 0.65 A$$
An order of magnitude less than a typical Raspberry Pi optically isolated relay shield can do.
Is there anything I should be aware of when choosing the board? Anything I'm missing here?

I doubt the printer will do that in idle when you turn on the printer, the power will be much less (no heating of the bed or the hot end).

@0scar I also doubt it'll be a problem, but I'd much rather know it won't. I hope someone here already knows and can share.

Yes it is safe to use such relay modules. Note that the printer will use less power than the specified power, when in idle it nearly doesn't use any power at all, the inrush current will be ver low when switching the relay. Furthermore, the relay is capable of handling the current according to its specification. Do note that you are using mains power, which can be dangerous, please make precautions working on mains (pull the plug from the socket) and shield the wires and use proper crimping tools, no solder.
I have done this with 2 printers, one where I cut the 230 V, but the latest one uses a computer 12 V PSU which has a separate wire (I think this is 5 V) which you can short to start the PSU; this is much safer. I used and use OctoPrint with custom shell scripts to turn on the printer and the hot end cooler fan as described in this answer.


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What's the accuracy and reliability difference between BLTouch, CRTouch and 3D touch?
What are the differences between the bed leveling probes BLTouch, CRTouch and 3DTouch in terms of reliability and accuracy?
Is there some kind of benchmark available? Also, how often should the plastic 'probes' in the BL and 3D touch be replaced? As that problem is solved in CRTouch.

The difference is that the BLTouch works, my other 4 clones don't... (from real experience, all 4 3D Touch sensors failed pretty soon after put to use, I really hope the quality of the clones is better these days).

This answer goes into the reliability aspects of the often-discussed "Touch sensors" within the 3D printing community based on experience with the BLTouch and the 3D Touch..
Throughout my journey in 3D printing, I've had the opportunity to experiment with various iterations of clones (from metal pins to plastic pins), referred to as the "3D Touch", attempting to emulate the renowned BLTouch sensor. One undeniable allure of these clones is their significantly lower price point, which tricked me into buying them being a budget-conscious 3D print enthusiast. However, it's essential to describe my experiences with these clones, which spanned up until 2019.
At first glance, these clones seemed promising, operating as expected and demonstrating competence in their initial usage. However, this initial phase was short-lived, as many of them eventually caved in to issues that severely impacted their reliability. These problems typically manifested in one of two ways: they either ceased to function altogether or exhibited erratic behavior by unpredictably deploying and retracting the probing pin during critical operations such as G28 and G29 G-code executions. The latter issue, characterized by premature pin deployment when the print bed was not adequately lowered (CoreXY), often resulted in disrupted Auto Bed Leveling (ABL, What is ABL or UBL? Is this the same?) sessions, leading to subpar print outcomes (actually no print at all...) and frustration.
In contrast, after making the switch to a genuine BLTouch sensor, the transformation in reliability was remarkable. It has faithfully served its purpose on my CoreXY printer for a continuous span of approximately five years, without a hint of trouble. The consistent and error-free performance of the authentic BLTouch has not only elevated the quality of my 3D prints but has also instilled confidence in the reliability of my 3D printing endeavors.
In essence, while cost-effective alternatives may initially appear enticing, investing in a genuine BLTouch sensor can undoubtedly pay itself in terms of frustration, reliability and long-term satisfaction. In hindsight, buying a genuine BLTouch would have actually saved me; "Penny wise, pound foolish" comes directly to mind.

I found Teaching Tech's comparison of probes quite thorough and informative: Six popular ABL probes compared: Accuracy, price, wiring and more! - YouTube
My take away was that all the ones he tested were more accurate than a hobbyist 3D printer needs, so it really comes down to convenience: which is the easier / cheaper option for your situation. He has this great infographic in his video's conclusion:

He also published a Google Doc with his results: TT testing - Google Sheets


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PrusaSlicer: How do I preserve the location of (interlocking) parts in a muliti-part model exported from OnShape / Blender?
How do you import a multi-part object into PrusaSlicer without losing the position of the parts? For example, I want to print a two-material interlocking structure like this:

I've tried exporting this from my CAD software (OnShape) as a mesh (STL or OBJ) but when I import it into PrusaSlicer (v2.7.0) the result is either a single object with no internal walls:

or (3MF) two objects placed on the build plate individually, so they no longer interlock:

If I use a STEP file it at least preserves the position of the parts within a single object, and there are some internal walls, but no internal top and bottom layers which I want for structural reasons (in this case the dovetail will simply crush in the XY plane if the part is tensioned in the Z axis):

What's a good way to import multiple parts and have them "print in place", like they were in the original design?

I've found a way to do this, which I'll document here in case it helps someone else in the future.

Export your parts as a single STEP file
Import that STEP file into PrusaSlicer
Set Print Settings > Multiple Extruders > Advanced > Interface shells

(You need to be in Expert mode to see this option)

The STEP file adds the internal walls, and this interface shells option adds the internal top and bottom layers I was missing:

Despite how featureless the STL mesh looks when imported, all the data is there and you can split it to parts using the right click menu. I feel silly for now having spotted this before .

The result is exactly as I had hoped:

My take away is that PrusaSlicer does not always prompt you to split your important mesh into multiple parts; so its always worth attempting to split to parts using the menu after import.


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Bottom messing up

We are having an issue where the bottom of every print is not sticking to the bed but the brim is great but when it starts the print it start in the corner and the filament does not lay flat.

Hi welcome to 3DPrinting.SE! Could you add a photo while printing half-way the first layer? (So that we can see the brim and part of the layer) What print speeds, temperatures for hotend and bed and what print speeds are you using?

What's your actual question? How this problem is classified? What the cause of it is? How it can be fixed? Try to formulate an actual question in the title.

I assume that's a photo of the bottom of a print?
To my eyes that looks like the filament is being squished into the bed way too much, which may result in it being dragged along with the nozzle, which causes it to curl up behind the nozzle a detach.
Try increasing your Z-offset, so the nozzle is slightly higher than it is now.
... it also looks like the filament is not sticking to itself at all. What type of filament is that, what print settings did you use, and what sort of bed surface do you use (PEI? Is it heated?)? Make sure the bed is clean - I recommend using soap and water to clean it like you would your hands, and then isopropyl alcohol to remove any oils your fingers (or moisturiser in the soap) may have left.
The usual steps for poor bed adhesion are:

Clean the bed properly
Slow down the print
Increase the temperature of the bed (~60 °C for PLA is usual)

If none of that worked, you can try putting down a layer of gluestick (like you used as a child, i.e. PVA glue). It is water soluble, so you can just wash it off the part and bed when you are done.
You can also buy specialist glues like 3Dlac if nothing else seems to work.


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Is there an easy way to slice any file containing planar or non-planar patterns for a 5-axis printer?
I am reading into 5-axis printers as shown below in a modified Prusa i3 by Jenny List:

The process of printing non-planar patterns on a 5-axis printer is intriguing to watch, as shown below by Garth Benson:

Source: YouTube.com
The slicing tools available for 5-axis printers are pretty limited, to my understanding. Is there an easy way to slice any file containing planar or non-planar patterns for a 5-axis printer such as the Open5x?

How are your Python skills?

Good enough. Math however . That's why I added 'easy' on purpose.


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How to reduce vibration on a camera arm connected to the printer bed?
I printed a Raspberry Pi camera arm for my Ender 3 V2 as a second camera that's not connected statically to the printer frame but to the printer bed instead. I now have two cameras, both from different angles, each with advantages.
However, the moving bed results in severe vibration. I need anti-vibration or stabilization methods for my very light Raspberry Pi camera. I was thinking about doing something with some rubber bands somehow or making a mold to make a silicon block(s) that I will use to replace some part(s) in the middle of the arm, disconnecting the plastic so it can potentially absorb some vibration.
Below is an example of the vibration viewed from my Raspberry Pi camera. The image is cropped, speed up and compressed to fit in an animated GIF under 2 MB for this site. The original is in higher resolution but the vibration is visible.

Can you post image of the arm, and how it is mounted to the bed?

I used to have a camera on the moving bed, never had the issue, so this comes down to design probably. Please share your mount.

I linked the design on Thingiverse in the question.

Looking at the project you linked, there is a couple of things you should consider to reduce vibration:

More points of contact. One point gives your arm a lot of freedom left-right, and not insignificant amount of up-down flex. For a 3D construction, ideally you would have N+1 = 4 mounting points.

Camera mount not on rotating axis. This, again, is a point of freedom that can vibrate very well. Glue it up or redesign,

Make it as light as possible. This arm looks way heavier than it needs to, especially at the end. It can very well narrow down towards the end significantly without significant stiffness reduction.

Use wider lenses and shorter arm. Shorter arm will vibrate less.

Make sure your cable is not an issue - it should move easily with the camera. Secure it along the arm so it cannot pull on the camera at all. Make sure it is short enough not to hook on anything. Make sure it's long enough not to pull on anything in any position. If these are contradictory, redesign for them to not be.

Every object or structure has one or more criticals, i.e. frequencies at which it will resonate if excited by a source of kinetic energy vibrating near one of the criticals. A relatively small vibration close to a critical frequency can excite a very large vibration in an object whose physical properties cause it to resonate at that frequency. Resonance occurs when the vibration cycles are in phase and reinforce themselves.
3D printers, with pulsed motors and moving parts operating across a wide spectrum of speeds, will certainly produce a broad range of vibration frequencies. Some of those might excite an object or structure physically connected to them.
Common engineering practice for suppressing vibration at or near criticals consists of making changes to one or more of these - excitation frequency, mass or stiffness. Nothing else will be effective.
It's probably impractical to try to change or dampen the myriad vibrations that a 3D printer produces. You'll most likely have more success trying to change the mass or stiffness of whatever is experiencing unacceptable levels of vibration.  It should be noted that in some cases reducing mass or stiffness can be as effective as increasing them. The objective is to move the object's critical frequencies away from the frequency of whatever is exciting it. This is often a trial and error process.

Meaning that Input Shaping could potentially reduce this too?

I'm not sure exactly what you mean by Input Shaping but it sounds like trying to manage the vibrations of the printing process. I doubt that will do much good because the process can include a relatively broad spectrum of frequencies.

I mounted my Pi camera for Octoprint to the table, rather than the frame of the printer; works fine for me.
If you have a long lever arm it will vibrate. So try for more points of contact with the frame.  Three would be ideal, nit one is definitely insufficient.
Another option is to mount the camera directly to the printer head - that seems to be common for super-short focus endoscope-style cameras.

Thank you, but it doesn't answer the question. I have one camera in a static position on the printer already, without vibration. This means that in that picture, the bed moves, but the printer doesn't. This second camera is on purpose bed connected for a different view and focus, static position to the print, instead of the printer. In that picture, the frame is moving instead, not the bed. I'm planning on a third (endoscope) cam focussed closely on the nozzle, which is another purpose again.

That description strongly implies that there is vibration between the frame and the bed.  The camera(s) may be solidly fixed to one or another of them but will still "see" the other part of the printer moving with respect to it. The camera mounting may not be the culprit if frame and bed are vibrating with respect to one another.


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Is an unlevel bed the reason I have trouble getting prints off a SpiderSheet?
I've had a lot of trouble getting prints off of my build plate. So much so that I ripped off the SpiderSheet, cleaned the glass thoroughly, and applied a new one.

I ended up stopping the 1st print I did because it looked like the nozzle was digging into the bed. I had to go to 220 °C with this PLA because otherwise, it's all fluff. Is my issue perhaps an unlevel bed?

I run a Creality Ender-2 with an older firmware.

What's your question? I suggest to change the title into an actual question.

If you have glass, why do you put a sheet on it? Glass is a perfect build surface. I have to agree with @BobOrtiz, what is your question? Do you want to ask why your prints stick so well, or why the nozzle digs in the new build surface. Please update your question so that it can be answered.

Well, if the nozzle digs into the bed, then that means the nozzle is too close to the bed. That has nothing to do with the Spider Sheet or whatever other surface you are using. Two reasons come to mind:

Your bed is uneven/warped. While glass plates are normally pretty flat, you can bend them by clamping them down to a warped heated aluminum base.

Your X/Y axes (the guide rods) might be bent a little. If the bed or head is higher/lower in some positions than others, then the nozzle will touch the bed in some positions. Even if your bed were perfectly flat.

Possible solutions:

Re-level your bed (hopefully you have already done this before asking this question).
Add mesh bed leveling to your printer (don't know if your printer supports it though).

Another solution would be to increase the distance and flow rate on the first layer, and see if it's evenly squished. And if it's not, see if it is something op is willing to live with.


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Why does Cura remove a part of a model when slicing?
Some parts of this model when slicing in Cura are just being deleted.
Here is the part of the model before slicing; notice how there is a wall between the threads and the inside

And after slicing, that wall is just gone, and this wouldn't be practical to print.

And turning on supports doesn't fix the problem in the slightest.

What the nozzle size 0.4mm? And what's the model height approximately, did you scale it?

Nozzle is 0.4mm, scale is X: ~75, Y: ~75, Z: 45.5, I have not scaled the model at all.

What version of Cura do you use? Latest 5.5? My guess is that there is simply to little space in the model to be sliced in that resolution. I would probably change the design a bit, or scale the whole model up, or maybe it's fixable with using a higher Wall Line Count and Wall Thickness. I'm not sure.

I'm on 5.3.1, I'll try updating to 5.6 and changing the settings you suggested

Scaling it up seems to fix the issue, but I have to scale it up to almost 150% for it to work again, but I don't want to print this at this size, so changing the model seems to be the only option.

Print with a 0.2mm nozzle at higher resolution?

Sadly I don't have a smaller nozzle, I ended up using PrusaSlicer instead which got it right.

As mentioned in the comments. Probably the model contains too little space for the slicer to be able to slice for that nozzle size and resolution.
You have a few options:

Scale up the model
Use a smaller nozzle and a higher resolution
Change the model to include thicker walls

Maybe you can increase wall thickness in slicer settings and achieve the same, although I am not sure of it.
As mentioned by you, apparently PrusaSlicer did work. It's interesting to figure out what the actual difference is. Isn't it just the wrong visualization in Cura? Did you try to print that Cura-sliced model or preview it top-down layer for layer?

All of these solutions would for sure work; but none of them are applicable to this model. I got this model from online and changing it would be a hassle, I don't have a smaller nozzle, and I would have to scale it up a ton for it to work. Cura's preview was very confident about printing it the way it showed, so I don't think it was a rendering bug. PrusaSlicer seems to be more lenient with very thin walls, so it sliced correctly.

Note: If the walls are really less than 0.4 mm thick, then that thread will be very fragile, even if you get it to print correctly.


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What are the potential benefits of using ferrite rings on the stepper motor wires regarding performance or accuracy?
I understand that ferrite rings effectively reduce electromagnetic interference (EMI). However, I'm not sure how much stepper motors are exposed to EMI and, therefore, if adding ferrite rings to the stepper motor wires has any effect. I'm curious how the potential reduction in EMI might impact the accuracy, performance, and stability of stepper motors in a 3D printer.


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How to design a cable pull relief?
A thick power cable will go into my 3D-printed device, and I am looking for options to design a "pull relief" against the full pull power of a human.
Ideally, it should be designed mostly on a flat surface and heat-resistant.
For example, forming a U-loop from the cable and applying a zip tie provides perfect pull relief that I am unable to break with my hands.
However, I am struggling to translate that knowledge into some 3D-print-friendly design.
I've been thinking about creating a clamp of sorts consisting of two plastic elements, where the second one is pushed into the cable using a screw from the outside - am I going in a good direction?
Can you suggest a working design for such pull relief without the zip tie?
Some ideas for inspiration:

Power Cord/Cable Strain Relief
Strain relief clip 3D for print
Hillman 58236 0.375 Diameter Round Strain Relief Bushing

Welcome. It would be helpful to provide a sketch, drawing or model for what you're trying to achieve and ask a specific question about what you're trying to learn. I suggest reflecting that question in the title by editing your post.

This sounds more like a UI question than a "how can I get this to print successfully". Perhaps more detail as to how it relates to the 3D printing aspect could help.

This is what I can think of. The Z channel is where you lay your cable inside. Maybe this is something similar to your "U-loop"? This works by transforming the pulling force into the friction between the cable and the internal walls of the channel: The harder you pull, the bigger the friction it generates, thus keeping it in place. This can be totally 3d-printed flatly and the strength of this would depend on your 3d-printing material, thickness, which I think is enough for your goal.
Now, you need to think about the cons of this design:

Space consuming
Overbending your cable, damaging it
You need to know your cable size before implementing this design, as it requires a tight fit. This means you have to change the design if you want to use a thicker or thinner wire in the future in development

Hope it helps, feel free to point out other flaws of this design.

A common approach to "design a thing that must accomodate a thing" is to first model the thing you need accomodated, add technical margins, then boolean subtract it from a solid block. Then carve the rest of the block to a neater shape, removing unnecessary material, making screw holes and so on.
So, first make the U loop on the cable, with the zip ties, as you found working. Use vernier calipers to measure the real-world model then re-create it in CAD. Make it thicker by some 10-20% than your measurements. Then create a separate object - something very roughly the shape of the strain relief, without any cable channels, then use Boolean operation to subtract the cable from it. Add any stubs to keep the cable from escaping, mounts to keep the cable relief attached to whatever you need to attach it to, extra supports for strength where you suspect it could break, then print it. Try to fit the cable, chance it will work the first time over are slim, but you'll find where adjustments need to be made, and repeat the process until you have a working product.


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Nozzle hitting bed corner before it stars printing
I just got this Artillery Hornet printer. I am new to the 3D printing but the printer is not new.
The glass bed was leveled from the Marlin firmware menu (Motion > Bed leveling > Level corners) and I manually adjusted the distance of all corners to be exactly 0.1 mm from the nozzle.
The printer works fine but I am not satisfied with the glass bed which does have adhesion problems with PLA, it is difficult to print the first layer with a reasonably low temperature for the bed and filament.
What I wanted to do was to install a new PEI bed, but faced the following problem: before the printer started printing from G-code, the head would go to the bottom right corner and hit the glass bed with the nozzle once. Then it continues on the appropriate level. Since the nozzle is made of brass and the bed is glass it won't do any noticeable damage to the bed surface.
However, I am not entirely sure if it is safe for the nozzle or PEI that I am about to install. Is it normal that the printer would do something like this or does it need to be adjusted/fixed somehow?
Is this common or is this on purpose?
My understanding is that before printing, the head is parked at the home position. Therefore, the Z-axis limit sensor needs to be reached. This is the moment when it happens. This printer is not equipped with Automatic Bed Leveling (ABL).

I'm not familiar with your printer but I've had that happen as part of a filament heating routine where the nozzle touches the bed while the extruder heats up. The intention was to stop the filament from leaking out. In my case, it was part of the start G-code set up in my slicer.
You don't mention the slicer you are using so here is where you find it in the two I use:
Prusa Slicer: Printer settings tab > Left panel Custom G-code
Cura: Settings menu > Printer > Manage printers > Machine settings > Start G-code.


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How do I add a custom motor driver to Marlin?
I've been digging through the Marlin code from GitHub, and I'm hoping that someone could direct me where to add a custom motor driver. I figure someone here already is familiar with the code and it would save me a lot of time digging.
I know someone will ask why I'm asking how I can add my own drivers...

To find out if what I'm trying to do has already been done by someone else, or if there is something close I could tweak (code reuse).

I am attempting to make an absolutely minimal controller board that drives really small steppers. I can easily drive the steppers directly with four TTL outputs (with some output protection of course). I have already experimentally shown it works and is solid.

More important than the above, I'd like to give it a try just for the learning experience. As they say, "the journey is the destination".

Welcome Tom. I don't understand the sentence 'I know someone will ask why I'm asking why I'd add my own drivers.'. Can you clarify it by editing your post?

@BobOrtiz - Hmmm, it's interesting when you think about it. It would be better put "I know someone will ask why I'm asking how I can add my own drivers...". As it currently stands, the meaning is: "I know that someone will ask me why I am asking why...", which isn't correct - even though the actual meaning is clear. The OP is really asking "how can they add a driver" not "why should they bother". Good catch :-)

I updated the question with the @Greenonline's version. My experience with posting online questions is that there's usually a flurry of, "why do you want to do that?" responses. I was trying to head those off.

Also, this is a serious question, and so far I've only received verbiage and spelling edits.  Am I asking in the right forum? Is there somewhere better to ask this question?

I've tried to answer your main question although your second sub question suggest that you want to write a driver from scratch, and the title suggests that you only wonder 'how to add' an already existing custom driver.

Perhaps you could include stepper.h? That supports driving a stepper motor with an H-bridge such as a L298N. You could then use its step() function from within the Marlin code to interface with the library.

It is actually difficult to answer this question as the code is written to handle likely over a hundred different types of hardware, and multiple types of stepper hardware.
Starting from where the pins are actually defined up to the code that drives them, here's a quick breakdown.
The header files in src/pins/pins_*.h define the actual pins that are talking to the hardware. E.g. these files contain lots of #define preprocessor directive such as this #define that defines what pin on a certain processor controls the direction of the Z stepper motor;
#define Z_DIR_PIN 10

The header file indirection.h defines "higher level" #define's. Building on the above example, this macro is defined in indirection.h used to actually set the stepper motor direction.
#define Z_DIR_WRITE(STATE) WRITE(Z_DIR_PIN,INVERT_DIR(Z, STATE))

Finally, stepper.cpp will use the above macros to actually write to the hardware. As noted above the bulk of this code is #if/#else/#define preprocessor directives to support all of the many hardware/processor configurations. Stepper.h does have some even higher level macros, e.g.,
      #define Z_APPLY_DIR(FWD,Q) do{ \
        Z_DIR_WRITE(FWD); Z2_DIR_WRITE(INVERT_DIR(Z2_VS_Z, FWD)); \
        Z3_DIR_WRITE(INVERT_DIR(Z3_VS_Z, FWD)); Z4_DIR_WRITE(INVERT_DIR(Z4_VS_Z, FWD)); \
      }while(0)

I suspect that the code is heavily optimized (some written in assembly) ending up with very high-level concepts such as Bezier curve following tied directly with writing to the actual stepper.
Maybe I have stepped into a big problem with this code. It's difficult for someone who hasn't worked with it a lot to make simple changes. Maybe there is a need for a "simple stepper" driver that does not have a gazillion hardware dependencies that can be used for people like myself who just wish to do a quick experiment.

Note that the above answer does not mention how timing is accomplished.

Maybe your looking at different code? #define Z_APPLY_DIR . . .  is  definitely in my stepper.cpp, not in stepper.h.

Hi Tom, your last comment looks like to are trying to reply to someone. The way comments work is that you (usually) need to address someone using the @ symbol. Also the reply comment must be under the same post where the comment (that you are replying to) was made. As a new user, you might like to read How do comments work?. Also, FYI, note that comments are ephemeral in nature and tend to get deleted after a time. So, any additional info (that needs to be kept) should be edited into the question and not placed in comments.

I suggest reading the existing Marlin documentation that's available regarding stepper drivers or trinamic drivers.
It's probably also advisable to familiarize yourself with the modular files src/module/stepper.h, src/module/stepper.cpp files, or from the Voxel8 repository for example the stepper_indirection.h file, as they handle the stepper motor interface.
Understanding the existing code or even modifying an existing driver could help to achieve your objectives.
Also depending on your experience and requirements you might find some inspiration in several YouTube videos such as DIY Stepper Motor Driver From Scratch or
EasyDriver A3967 Stepper Motor Driver Tutorial with Arduino Code.

I've already been through the above. The documentation (mostly how to set #define's, not what I'm looking for), stepper.cpp appears to be dealing with mostly high level stuff, i.e., I see lots of code for bezier splines, etc. Maybe my problem is digging though reams of #if's and #defines just to find the code that actually talks to the hardware is such a pain.

With regard to the videos; I've been writing code like this for decades, I don't need the "how a stepper motor works" answers. I already use an Arduino for proof-of-concept (as noted in my question). My question relates specifically how and where to add drivers to Marlin.

Although the question fits on this site too, I think you might have more luck asking this on GitHub with the context you've just described, as in, what you've already achieved and tried.


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Overlapping filament after increasing speeds Prusa Slicer
I'm trying to tweak my speeds to see what I can get out of my printer.
I have an Ender 3 v2 with dual Z steppers, E3D Hemera XS and Klipper with a 0.4 nozzle printing PETG Filament.
After changing the speeds I started getting this at the end of the lines:

It is where the nozzle turns back for the next line. I'm trying to find out if there is a setting to fix this but I'm struggling with what to search for.
What would this be called and is there a settings that can change this?
Speeds:
Perimeters = 60 mm/s
Small perimeters = 15 mm/s
External perimeters = 50%
Infill = 80 mm/s
Solid infill = 40 mm/s
Top solid infill = 15 mm/s
Layer height = 0.2mm

Hi, welcome to 3DPrinting.SE! What speeds are you printing? PETG is known for not being able to be printed really fast. Please update your question and post the speeds you use.

Thanks for the edit Oscar. Speeds added.

This looks like your Pressure Advance might not be tuned correctly. At higher speeds, PA is practically a necessity. I found that Ellis' PA Pattern is quite good for this purpose (it's also integrated into OrcaSlicer, if you use that).

I haven't got pressure advance configured yet. I'll take a look at the docs and Ellis' PA Pattern. Thanks.


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Experiencing Under-Extrusion and Print Instability on CReality CR6 SE with Various PLA Filaments
I am facing persistent issues with under-extrusion and print instability on my Creality CR6 SE 3D printer. Despite using different PLA filaments from various manufacturers such as Eryone, Jayo, Prusament, Redline, and Amazon Basic, I consistently encounter problems with thin lines and unreliable prints.
Notably, the same filaments perform well on my Prusa Mini, ruling out filament quality as the sole culprit.

Here are the key details:

Running the latest Community Firmware.
PLA filaments are stored adequately, ranging from a few weeks to several years old.
Hotend temperature settings range from 205-215 °C with a 60 °C heated bed.
Standard settings slightly modified for wider inner perimeters (0.6 mm) and higher temperature for stability.
Occasional difficulties during filament changes, even with the extruder released and the nozzle adequately heated.

I have performed some troubleshooting steps, including changing filaments, adjusting Z offset, and ensuring proper storage conditions. However, the issue persists. I also cleaned the extruder. Could it helb to replace the PTFE tube with a Capricorn tube?
Are there additional steps I should consider or specific settings that could be impacting my print quality? Any insights or guidance would be greatly appreciated.
I have checked other questions on this site, but with no helpfull result for me.

Try following a guide on debugging under-extrusion all the way through.
The most obvious point you did not list in your question are: checking the mechanics of the extruder and cleaning the nozzle:

Making sure the extruder gear theeth are clean and sharp
Ensure proper spring tension is pressing the filament to the extruder gear
Check if the motor has enough force/current to push the filament through your fingers if you press them together
Calibrate the E-Steps
Check that volumetric E is not enabled in your slicer settings.
Make sure you can manually push filament through the heated nozzle without too much force
Perform a cold pull or several
etc.


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Can you use Power-loss Recovery when printing from OctoPrint?
As per the Marlin documentation for G-code M413 - Power-loss Recovery:

When Power-loss Recovery is enabled, and Marlin runs a print job from the SD Card or Flash Drive, it periodically saves the print job state to the SD Card / Flash Drive. If the machine crashes or a power outage occurs, Marlin presents the option to resume the interrupted print job.

If the printer is controlled by a host over USB instead (such as OctoPrint), can you still use Power-loss Recovery?

There is an OctoPrint plugin that attempts to achieve exactly that. The plugin is called OctoPrint-PowerFailure and it's page describes:

OctoPrint-PowerFailure attempts to recover a print after a power failure or printer disconnect. It is intended as a last resort and does not replace the use of proper power backup and appropriate communication setups. Recovered parts are certain to show small defects, but this may be acceptable in some cases.


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What could be the underlying reasons for the spaces or voids between the layers?
I've been attempting to 3D print a hollow cube, but I'm encountering issues with noticeable gaps between the walls. Despite adjusting the Extrusion multiplier and width settings, the results remain unchanged. Can someone provide guidance on how to address this issue or suggest alternative parameters to tweak for a more solid print?

Filament Used: eSun ePLA-HS High-Speed Filament 1.75 mm
Bed Temp: 60 °C
Nozzle Temp: 220 °C

While the question is tagged with a slicer tag, this clearly should need at least a tag of the printer, this is most probably not a slicer issue but a hardware issue.

I was not able to tag the printer but the printer  I'm using is Creat-bot F430

What could be the underlying reasons for the spaces or voids between the layers?

Underextrusion is what is called the phenomenon you see.
For a calibrated printer, which is pretty much how you get them delivered, there should not be any fiddling with the extrusion multiplier parameter necessary to get reasonable prints.
When underextrusion appears in your prints, this usually suggests that something is wrong in the extruder to spool to nozzle path.
Many of the underextrusion can be related to e.g. (this is an example list and may not be complete, but, given the question it is hard to pinpoint to a specific issue):

Too much friction on the spool,

Entangled, or tight winded filament
Too much friction in unrolling/turning the spool

Obstructions in the nozzle

Carbonized debris in the nozzle
Problems with the PTFE tube in the heat break

Problems with the extruder

Slipping/skipping filament; not enoungh force to move the filament
Grinding filament; too much force to move the filament

etc.

You need to do some troubleshooting, inspecting and cleaning of the complete extrusion path and address any problem you encounter.

Thank you for the information . I've taken apart the extruder and examined the heat-break and it look like  the PTFE tube is worn out.

@S_D Thanks for the feedback and good to see the problem you faced falls in the category Problems with the PTFE tube in the heat break


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TPE print fail - filament fails to extrude after normal start
It is my first time printing flexible filaments.
I have been trying to print a flexible case for my mini-PC using the TPE 83A by eSun on my KP3S pro.
Whenever I try to print it starts well, then after printing a few strokes, the print systematically fails.
It is not an adhesion/levelling problem as I installed a BLTouch probe and made a 12x12 points grid of my 200x200 printing bed, which works perfectly with PLA.
It seems that after printing a few lines, the nozzle just stopped extruding filament anymore (see photos); although the extrusion gear still seems to be turning.
FYI my nozzle is a hardened steel nozzle, that I recently acquired to replace the original brass nozzle (because I wanted to print abrasive filament). Could it be the problem? I read that a hardened steel nozzle may not conduct heat as well. I did try a wide range of temperatures and saw the same results; also given the small size of the MK8 nozzle used by the KP3S, I would wager that heat losses due to poor heat conductivity of the nozzle may not be as important no? (I guess that the delta in temperature between the contact point with the heating  also depends on the length of the nozzle)
Other information:

I print in an enclosure
I try to keep my filament dry by using a heating box + desiccant
Also the filament doesn't seem to warp, the filament that is on the bed seems to be well adhered. The problem seems to come from the "extrusion system", whereby the filament just stops extruding.
I used the recommended printing profile for flexible filament (e.g. reducing speed to 35 mm/s for top speed and to 20 mm/s for the first layers, retraction distance at 1 mm)

Any idea of what might be happening? I gleaned a lot of info from Proper settings for printing rubber and rubber-like materials? on printing flexible filaments. I will perform a bunch of tweaks based on that question to hopefully troubleshoot my way to a proper print through trial and error; however, it would be nice if someone has a better idea that could direct me as to what could be the problem given the symptoms observed.

After several months of trial and error with this filament, I finally managed to understand the issue.
It was a mechanical issue due to the filament sensor of the KP3S Pro.
The out of the box setup of the KP3S pro is with the filament roll being set on rollers and passed into a filament sensor to anticipate situations where filament is running out.

However, this sensor applies pressure on the filament, and it creates a mechanical strain that prevents more elastic materials from being pushed through the extruder.
In order to lessen the mechanical strain on the filament I mounted it over the machine with a spool holder, and stopped using the filament sensor when printing my eSun eLastic TPE 83-A. I found this video, Kingroon KP3S Pro Top Mount Spool Holder in Detail
, which uses a KP3S spool mount model which can easily be adapted to the KP3S pro.
Thus the filament feeds directly in the drive, and I have no problem printing this flexible filament.

I may (or may not) explore a bit more in the future to see if I can tinker with the pressure of the filament sensor so that I can take advantage of it also with flexible/elastic filaments. But for now I will be printing flexible filament without using the filament sensor.
I won't go in detail about the parameters I used yet for this filament, because I am still exploring the best parameters for this filament. But this issue really was the core of my problem and I could already obtain very satisfactory results with my KP3S Pro printing this eSun TPE-83A.

Depending on your extruder geometry, you might have to slow down even more. I can't print TPU at 35 mm/s on my extruder, at least.
The problem with flexible materials is that they really don't like to be pushed into a narrow hole. Instead, the filament between the extruder gear and the heatbreak will buckle and bend to the side, forming a loop inside your extruder housing. If that happens, there is no more pressure and the extrusion stops. See Proper settings for printing rubber and rubber-like materials? for a very detailed analysis and tips.
If you use PrusaSlicer or a derivative, a good option to limit the extruder speed for a specific filament is Max Volumetric Speed. That way you can limit the speed for all types of extrusion with a single number, instead of many speed options in the print profile. I'm not sure, but I don't think that Cura has a comparable setting.

Thank you for the reply. I am using Cura, I will see about MVS. I will try to further tweak the speed, however, the initial layer speed is 20 mm/s (35 mm/s is top speed, will clarify the post).
Thank you for the buckling tip, I had noted it as one of the possibility.
However I noted during my tests that when I run multiple extrusion tests with the TPE back to back I have no problem. Is it common that extrusion tests would work but extrusion would fail? Also my extruder [ https://wiki.e3d-online.com/Titan_Assembly ] is designed with a drive to avoid buckling.

Well, squeezing the molten filament to the bed does create some back-pressure on the extruder. So it is absolutely possible that printing extrusions fail but extruding in thin air works. I guess you will just have to experiment what works, rather than theorizing.


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Is there a possibility to reliably print PLA with an Ender 3 that has an all-metal hot end?
I want to use my Ender 3 as a multi-filament-printing printer
As many users already have asked, printing PLA with an all-metal hot end is not really recommended.
But, if I am attempting to use my stock Ender 3 printer (no hardware and software modifications) as a safe indoor 3D printer that can both print PLA and PETG, without risking any fumes coming out of the PTFE tubes.
How may I reliably print PLA with an all-metal heat break, without any further hardware modifications?
Are there any reliable slicer settings (such as print speed, retraction, etc.) that should be systematically tried?

All printers are at least a bit smelly/fumey.  If you want to avoid that, an enclosure that is vented through a filter, or vented outside is a solution.

Can you expand a bit on what you mean by "printing PLA with an all-metal hot end is not really recommended."? Prusa printers are known to be reliable, and have all metal hotends. I've been printing PLA on my Prusa MINI+ for years very reliably (and more recently a Prusa XL, again with all-metal hotend).

You can look up the material properties of Polytetrafluoroethylene (PTFE) and see that its glass transition temperature (when it softens) is around 115 °C, and it melts at 327 °C. The PTFE in a not-all-metal hotend will be in the heatbreak which is significantly colder than the hotend, and should not reach 115 °C.
The plastic casing which holds the heatbreak is typically injection molded ABS which softens at 105 °C. So your hotend would begin to shift in a softened carriage before the PTFE began to soften.
The fumes you are worried about are caused by off gassing, which may be a better term to search for if you want something with hard numbers you can reason with.
That said, if you can reason about the maximum temperature your PTFE will experience in the heatbreak (which should be significantly colder than the temperature of the nozzle), you can use this safety chart to reason about how dangerous (or not) it is to be near (see Capricorn's Safety Precautions).

As regards the safety of an indoor printer, PLA does not emit a lot of Volatile Organic Compounds (VOCs) and is generally deemed "safe". (ABS is known to emit a lot, and is known to cause headaches). PETG seems to emit more than PLA, but still low at 550 parts per billion (ppb).
That said, all plastics emit some amount of VOCs when heated, so it is always best to print in a well-ventilated area. Personally, I print in my bedroom and spare room and just leave the doors to the rest of the house open, and those little vent slots you get at the top of windows have been enough to keep the air in the house fresh.
(If I print ASA or ABS I absolutely close the doors during printing, then air the room with an open window for 10-20 min when it is done: you don't want the ambient temperature too low when printing - causes excessive warping and other issues).


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Problem leveling printer bed after reassembling after move
I'm not new to 3D printing, but am not extremely conversant in doing mechanical adjustments on the printer.
I took the printer down (minimal de-construction), loaded it into a padded box and drove it to my new home when I moved last year to avoid the handling that it would receive from movers.
Since then, I cannot get the bed to level properly regardless of what I do with the leveling screws.  No matter what I do, the left rear corner is way too high for the nozzle and starts to scrape if I try to move it into place. I've tried every adjustment that I can find/think of other than taking the printer apart and re-building it (which I do not want to do if I can avoid it). I'm using the (often recommended) yellow springs that I bought off of Amazon and have a glass print bed.
Any suggestions how I can level the bed without taking the printer apart?

Hi John, welcome to 3DPrinting.SE! Pictures are generally very welcome, is it possible to add some to provide context. E.g. you day you have a glass bed, that should be very flat. Place a ruler on its side over the bed to check the level of the glass. If that is straight, you need to look further into the Y-axis construction or the portal itself.

I will take pics this weekend and will update the post.  Thank you!

Where do you live? I want to move there! Very long weekends over there!

What does "minimal deconstruction" mean? Photos of the screws and what's happening when you turn them could be a great help as well.

It may be that the surface the printer is sitting on is not planar. That can deform the frame slightly or cause a soft foot condition. Either of those can result in Y guide rods being non-linear.  The cure, if that's the case, is either adjustable feet or shimming the high foot/feet.

Step 1: remove the glass and clean up its underside as well as the aluminium base. Some sort of debris stuck under the glass is often the cause.
Step 2: Tighten the eccentric nuts on the bed rollers (then tighten the screws holding them). At least some of the rollers are mounted on special nuts that can be turned to move the roller away/into the rail, make sure all the rollers can be turned with some resistance, loose=no grip, no turn=too much friction.
Step 3. Besides surface, as Allardjd instructs, check for crud stuck to underside of the printer legs. A twist in the frame can introduce this sort of problem.
If all else fails, invest in an auto bed leveling probe, it solves this sort of problems automatically and it's a huge quality-of-life improvement.


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How to print more accurately 3D cube test?
I have print problems with my Creality Ender 3 S1 and I have calibrated all axes:

Belts both X and Y axex
Extremes of the X-axis horizontal structure have the same distance to the bottom of the printer
Wheels both the X-axis and Y-axis (wheels under the bed) are correct

However, after I printed the cube the results weren't good enough. Print details:

I have provided the 3mf file
PLA
Ender 3 S1
0,24 mm (first layer 0,20 mm)
Speed: perimeters 60 mm/s (external perimeters 50 %)
Speed: solid infill 30 mm/s; top solid infill 15 mm/s

Usually the first layer is bigger than the rest. How fast are you printing? It looks as if it is printed really fast.

@0scar I updated the post with data about print speed, however I answer your question below:

Speed: perimeters 60mm/s (external perimeters 50%)
Speed: solid infill 30mm/s; top solid infill 15mm/s


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Poor layer adhesion on only one layer of PETG print
One layer of PETG is not printing correctly
I’ve successfully been able to print in PETG, and it looks perfect except for a random layer in the middle of the print. It adheres to the bed fine, and the rest of the layers are fine, but one in the middle appears detached and weak. You can see the line in the plastic that goes all the way around. Any idea why?
This is the second time printing. I thought maybe there was a power issue or something while printing that caused it, but now I have the same effect again.
I have an Ender 3 Pro with a spider hotend and use Overture PETG. Nozzle at 255 °C and bed at 85 °C (initial layer is 260 °C and 90 °C), no fan, 90 mm/s speed.

Have you checked the gcode to make sure there aren't actually missing extrusions in that layer? Some versions of Cura have a bug where they'll omit large parts of a particular layer. If that's not the problem, look for anything different in that layer of the gcode preview that might be related (odd travels, etc.)

Nothing strange in the GCode


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How can I reduce stringing on very small parts?
I'm trying to print a 30% version of this High Bypass Engine Nacelle, but I'm having some quality issues with the high pressure turbine compression stages.
I've uploaded several photos to Imgur here, ill include some below:

What's odd is that the stators, which are very similar in size and overhangs, seem to print much better. Here's a photo of that:

I have printed several retraction tower tests and selected the best values, but it doesn't seem to improve all that much. Whenever I print larger components, they seem to print just fine with very little or no stringing on the surface.
Filaments tested

HATCHBOX 1.75mm Silk Bronze PLA
AMOLEN Silk PLA Filament, Silver Grey
AMOLEN Silk PLA Filament, Black

Settings

Ender 3 S1 Pro (running klipper)
Nozzle: 0.4 mm
Sliced with Cura
Layer height: 0.2 mm, 0.16 mm
Print speed: 50 mm/s, 80 mm/s, 100 mm/s
Walls: 4
Wall ordering: Inside to Outside (my default), and Outside to Inside
Top: 3
Bottom: 3
Infill (doesn't matter, the walls/top/bottom make it 100%)
Retraction:

Speed: 25 mm/s, 30 mm/s, 35 mm/s
Distance: 0.5 mm, 0.8 mm, 1 mm
Retract on layer change: Yes
Retraction minimum travel: 1.5 mm, 1 mm

Coasting: Disabled
Temperature:

Extruder: 190 °C, 200 °C, 210 °C, 215 °C
Bed: 60 °C

Wipe:

Outer wall: 0.5 mm
Infill: 0.1 mm

Print thin walls: enabled
Combing: Not in skin

I'm not sure what other settings to share that would help troubleshoot this. If there's more detail that would help, lmk and ill add it.

IMHO you are pushing to the limits with an affordable economical printer, too small/detailed parts and a too wide nozzle. You could lower the speed, layer height and increase part cooling maybe.

@oscar - Idk, I've been able to print very tiny screws with very fine threads (I think it was M4, printed at 0.12mm layer height). I don't see how this can be more complicated than that. Especially considering I can print the stators.
A friend pointed out that it may be due to the volumetric flow rate, it doesn't have room to go very quick, so the filament dwells in the hot end too long and overheats.
Im going to try a print at a lower temperature, again. lol.


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Extruder motor doesn't pull filament during job only
I have a weird problem over here, I'm restoring an FLSUN Kossel Mini (with a RAMPS 1.4 board) and it printed fine for the last two days.
Now when I initiate a print job, the extruder motor doesn't push filament into the nozzle ( it retracts filament like it's supposed to, it just doesn't push.) and this only happens during a print job.

I cleaned the nozzle
Increased/decreased printing temp.
Swapped motor drivers.
Adjusted Z offset.
Reset the motherboard.
Changed acc and jerk values.

None of these did the trick for me, and when I manually control the extruder motor (from the LCD or Repetier) it pushes the filament without any problems.

Is it turning at all? Are there signs of filament grind? Does it fail from the start or at some point during the print?  Is coldside hot?..

Yes it turns fine, and the whole extruder assymbly is clean from any grind or debris.

The extruder doesn't pull filament from the start of the job, but weirdly enough it retracts the fillament when z hopping.

Are you sure you are sending good gcode? And have you tried to remove hotend altogether, to make sure it has no part in the issue?

Yes I did, first I used the didcated extruder buttons on repetier then tried with G1 commands, and both seemed to move the stepper motor fine.

Another thing I noticed was fillament wasn't extruded on the first 3 layers, when the print job reaches layer 4 the extruder motor returns to pumb fillament.

I eleminated the clogging/jaming possibility by romoving the filament wire and starting a print job.

This is when I found about the 3 layers problem.

Can the extruder stepper be damaged in this case?

Extruder motor works or it does not. It's not layer dependent. It seems your works. Check hour hcode


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All else being equal, is there a reason to go with 5, 12 or 24 V fan?
I'm looking for fans for my upcoming printer. In each common voltage, 5, 12 and 24 V, I see fans with the same advertised rpm, cfm, static pressure and noise.
So, if all else is really equal, are there any important reasons to go with one of these voltages over the others?
My PSU will obviously be a 24 V, like most of the recent designs, so there's no obviously problematic step-up converters. Step-downs for fans are included in most of the mainboards and toolhead boards, so I don't think that's an issue either, but maybe there's something I don't know?

Where will the fan be, is it a parts cooling fan for your hot end or for an enclosure?
Will this be your main parts cooling fan or an auxiliary one?
First, check your main board, it may be a 24 V board, but does it have spare headers for 24 V, 12 V, or 5 V. Check that the Amps match too. You can have a higher amp rating on your main board than your fan without doing any damage, but not vice versa (The device supplying the power must be greater than or equal to the device receiving it).
Next, check that your main board has the spare capacity to control the fan and that the fan has a matching mechanism to be controlled. Some fans have a dedicated control wire, some are controlled by the main board varying the power level that is supplied to them.
If you don't have a matching control method then your fan will be always on\off and always at 100 % speed. Which may not be desirable for you.
Once you have checked these things, narrow down the fans available to you based on these criteria, rather than voltage.
Generally speaking (and I mean very generally) the higher the voltage the less "effort" the fan needs to go to to move the same volume of air. So if a 5 V fan and a 24 V fan claim to have the exact same specifications it would usually mean that the 5 V fan is pushing itself hard or the 24 V fan is underperforming.
Parts cooling fans and fans on the hot end are usually fast-moving and small, so they are normally lower voltage fans as they need to go lick a rocket but only to move a very small amount of air a short distance.
Fans in this case are usually slower moving but much larger, they need to move large volumes of air, so they need a higher voltage because they have to put in more effort (Greater effort = greater voltage requirement).
So, if you are offered a choice by your main board, go this way.
If you're not offered a choice, and you only have 24 V headers, then this is the way that your manufacturer intended you to go, and go for that instead.
I know that this isn't much help, but without knowing more details, such as the model and manufacturer, it's difficult to give more exact advice.


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Extruder feeding excessive material
I've been trying to print concrete using a 7mm nozzle. The issue I'm facing is my extruder is pushing too much material in the print head and material can't be extruded at the same rate from the nozzle while printing. As a result, more material gets accumulated in the print head and the tube gets disconnected from the print head like this in the picture. I have calibrated the E-steps, and also reduced the flow rate. Can anyone suggest me what settings I need to adjust to fix this issue? Thanks.

What printer is it? And what filament you are using?  What temperatures?

Uncommon setup. Interesting. @Mołot the 'filament' is concrete (beton). The nozzle is not -0.7mm but 7mm.

@Souvik can you share more information about what printer this is, what slicer and slicer settings you are using, how does the model look? What is your question? 'Why are my lines not straight?', 'Why is the extruder feeding excessive material?'. Please reflect that in the title. Keep in mind that concrete printing is unfamiliar to most users, the material (properties) are entirely different. I don't know much about it either but my initial guess would be that the composition of your concrete is too fluid? Can you share information about what mixture and composition of concrete you are use?

@BobOrtiz I'm using a Stoneflower multimaterial 3D printer and using Cura 5.2.1 for slicing the hollow square model. I'm using a 7mm nozzle. In cura, I used filament diameter (7 and 2.5mm) and calculated the E-steps value according to these numbers. If I use 2.5mm dia then the E-steps is 67.67, and if I use 7mm then it 530.53 steps/mm. I also changed the flow rate from 100 to 80 and 50%. Nothing worked. The extruder is pushing a lot of material and the material can't be extruded at the same rate. So, should I change the e-step value as I'm using a new motor now with higher torque than before.

@BobOrtiz For the concrete mix, yes it's a little bit more flowable compared to conventional concrete. It uses Cement, Silica Fume, Sand, Fly ash, Water, Superplasticizer, and Viscosity modifying agents. I have printed with this composition before. After changing the motor and printhead these issues arise. The previous motor had a torque of 48 Ncm and the new one has 55 Ncm. Could this be a potential issue?


text:
How do I reverse the state of an endstop in Klipper other than using an exclamation mark?
I have been messing with my Y-axis endstop since it keeps being triggered when not pressed but otherwise, it is working as intended. I have tried to use ! to reverse the state but it does not. I scoured all over the internet and documentation. All I've read just says "Use ! to reverse the state" but that has not helped. I have also tried changing if it's pull-up ^ or not to no avail.
Am I missing something obvious here or did I just bork it? I have included the printer.cfg for reference. The printer is an Ender 3 Max Neo so ignore the references to the V2 Neo.
# This file contains pin mappings for the stock 2022 Creality Ender 3
# V2 Neo. To use this config, during "make menuconfig" select the
# STM32F103 with a "28KiB bootloader" and serial (on USART1 PA10/PA9)
# communication.

# If you prefer a direct serial connection, in "make menuconfig"
# select "Enable extra low-level configuration options" and select
# serial (on USART3 PB11/PB10), which is broken out on the 10 pin IDC
# cable used for the LCD module as follows:
# 3: Tx, 4: Rx, 9: GND, 10: VCC

# Flash this firmware by copying "out/klipper.bin" to a SD card and
# turning on the printer with the card inserted. The firmware
# filename must end in ".bin" and must not match the last filename
# that was flashed.

# This also works for the GD32F303 based Creality 4.2.2 board.

# See docs/Config_Reference.md for a description of parameters.

[include mainsail.cfg]
[include Macros.cfg]

[stepper_x]
step_pin: PC2
dir_pin: PB9
enable_pin: !PC3
microsteps: 16
rotation_distance: 40
endstop_pin: ^PA5
position_endstop: 0
position_max: 310
homing_speed: 80
second_homing_speed: 20

[stepper_y]
step_pin: PB8
dir_pin: PB7
enable_pin: !PC3
microsteps: 16
rotation_distance: 40
endstop_pin: ^!PA6
position_endstop: 0
position_max: 315
homing_speed: 80
second_homing_speed: 20

[stepper_z]
step_pin: PB6
dir_pin: !PB5
enable_pin: !PC3
microsteps: 16
rotation_distance: 8
endstop_pin: probe:z_virtual_endstop
position_min: -5
position_max: 320
homing_speed: 4
second_homing_speed: 1
homing_retract_dist: 2.0

[extruder]
max_extrude_only_distance: 120.0
step_pin: PB4
dir_pin: PB3
enable_pin: !PC3
microsteps: 16
rotation_distance: 34.406
nozzle_diameter: 0.400
filament_diameter: 1.750
heater_pin: PA1
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PC5
min_temp: 0
max_temp: 250
control: watermark

[heater_bed]
heater_pin: PA2
sensor_type: EPCOS 100K B57560G104F
sensor_pin: PC4
control: watermark
min_temp: 0
max_temp: 130

[fan]
pin: PA0

[mcu]
serial: /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0
restart_method: command

[printer]
kinematics: cartesian
max_velocity: 300
max_accel: 5000
max_z_velocity: 5
square_corner_velocity: 5.0
max_z_accel: 100

[bltouch]
sensor_pin: PROBE_IN
control_pin: PROBE_OUT
x_offset: -37.75
y_offset: -14.0
z_offset: 0
speed: 20
samples: 1
sample_retract_dist: 8.0

[safe_z_home]
home_xy_position: 192.75,171.5
speed: 150
z_hop: 10
z_hop_speed: 10

[bed_mesh]
speed: 120
mesh_min: 10,10         # Need to handle head distance with cr-touch (bl_touch)
mesh_max: 300,300       # Max probe range
probe_count: 5,5
fade_start: 1
fade_end: 10
fade_target: 0
algorithm: bicubic

[bed_screws]
screw1:30,25
screw1_name:1
screw2:200,25
screw2_name:2
screw3:200,195
screw3_name:3
screw4:30,195
screw4_name:4

[screws_tilt_adjust]
screw1: 67, 42
screw1_name: front left screw
screw2: 237.60, 42
screw2_name: front right screw
screw3: 237.60, 212
screw3_name: rear right screw
screw4: 67.60, 212
screw4_name: rear left screw
horizontal_move_z: 10
speed: 200
screw_thread: CW-M4 # Use CW for Clockwise and CCW for Counter Clockwise

# [display]
# The Ender 3 v2 Neo's 4.3" LCD display is not supported by klipper

[filament_switch_sensor spool]
pause_on_runout: True
switch_pin: ^!PA6

[output_pin beeper]
pin: PB13
 ```

Welcome. What's your actual question? 'How to reverse the endstops state in Klipper?' please reflect that question in the title.

Why do you think you need to reverse the state? Your switch does not magically work different from every other mechanical NC endstop switch out there. If it's malfunctioning, something is likely wrong with the switch or the wiring, not the configuration.

@R..GitHubSTOPHELPINGICE I think I need to do that because no matter how I change the config for the endstop pin, I get the same TRIGGERED status when it is not pressed and OPEN when it is closed. I have tried both using ! and without it and its the same. Tried it with ^ and without too just in case and it was still the same.

Is that a NO or NC switch?

It's a NC switch. I checked with a multimeter when I noticed the issue since all I read was that it was normally because of a faulty endstop.


text:
How to connect Dremel 3D45 to a hidden WiFi network?
At office we have a hidden WiFi network. I'm not able to connect our Dremel 3D45 to this network, since when you tap on "WiFi" it scans for the available networks and it does not add the "Hidden network" item as usual.
I also tried to make the network visible for a while. Then I connected the 3D printer, but as soon as the network hides the SSID (even without bringing down the AP) the printer disconnects immediately.
Was anyone able to connect to a hidden network on Dremel 3D45?
Unfortunately, I cannot ask the IT to change this settings permanently.

Is this a work related use? Does the IT dept know you are wanting to connect this? The IT dept should be able to get this thing connected. "hidden" simply means it is not broadcasting the SSID. If you know the SSID and password, it should connect, hidden or otherwise.

@WPNSGuy have you ever tried to connect the Dremel 3D45 to a hidden network? I'm aware what is it, but I don't know how to do on this printer!

@WPNSGuy I mean, the question is not about networking in general, but is related to this model of 3D printer


text:
When is a leadscrew too bent and should be replaced?
I've bought an additional second hand printer and I noticed that the lead screw has been bent. I did not have any issues so far with prints that are only a few cm tall.
I filmed it from the top, next to a ruler, as shown below and put a grid over it for reference. I think it should be replaced. How bad is this? When should it actually be replaced?

It depends on all the rest of your Z axis motion system. It might be a huge deal or no problem at all. To answer,  we would need to see more.

It's an Ender 3 V2. What would you need to see?

Z whells on the Y gantry,  and the way teapezoidal nut is secured to it - can it wobble without entire gantry wobbling?

It's too bent when it starts to cause issues.
Really, it is that simple. If your prints looks good, you don't hear any screeching sounds, your motors are not losing steps, then you are good and just leave them be. Keep them clean, keep them lubed, and enjoy your hobby.
More specific to your situation, good set of lead screws, with guaranteed straightness and pitch consistency, can cost more than an used Ender 3. Decent "3D printing quality" set will cost less, but still a significant percentage of your machine worth. Enders are good bang for your buck, not because they have a lot of bang, but because how little is the buck. They are designed to be built with imprecise parts, and to still give acceptable quality. You can replace screws, replace V wheels with linear rails or rods and ball bearing, you can add input shaping by changing firmware to Klipper,  upgrade hotend, add enclosure, replace extruder with something lighter, and so on. But why?
By the time you will find and "fix" all the quirks of your Ender, you will spend enough to build Voron or RatRig, or to buy one of the Bambu Labs printers or Prusa kits. And that's what I'd do, but if you prefer to tinker, if that's your hobby, go for it. Just remember, it doesn't make economical sense.
To reiterate, if it works acceptably, don't fix it. Unless it's for fun.

The third paragraph is a huge exaggeration, and arguably the second is as well. The way the Z axis is designed using V rollers, the lead screw plays very little role in horizontal offset/Z wobble. It's designed not to care if it's bent, until it's so bad that it binds. Whatever problems your Ender 3 might have, you can get it up to excellent quality with under $200. Far less than the options you're claiming are more economical.

@R..GitHubSTOPHELPINGICE I wrote that they are designed to not care about imprecise parts. Didn't name bent screws specifically, but in first paragraph I described effects of screw binding in a way easy to understand.  So on that topic you just repeated what I wrote using different words. For the "economical" part you either didn't read what I wrote or misunderstood. I claimed that's more economical to buy a printer that already has all these upgrades than to put them on Ender. And I did say not to do it if someone is happy with the quality.  Your excellent quality claim is exaggeration.

It's really not. During this year's TFT, I had a lot less quality problems than a bunch of Bambu users on the Discord did, running an Ender whose total cost with upgrades was less than half the Bambus. And it was printing a lot faster than them.

An Ender is a machine that needs tinkering with now and then. The wheels need frequent tightening because of wear for exmaple. They are built as cheap as possible to get fairly high precision, but with in mind that it won't last forever without some maintenance now and then. Almost all Enders have a bulged build plate for example. Nothing a bltouch won't solve, nevertheless a piece of cheap junk that is worth its place in the market.

Cause and effect
Bent screws can cause an effect known as Z-wobble. But, to mitigate this, the non-driven side of the lead screw is left unconstrained. This is intentionally designed as such.
This means that as long as the linear guide (being V-slot with rollers, linear shafts or linear rails) are sufficiently guiding the carriage, a little bent screw would not cause too much problems in the print result.
Note that the animated gif shows the end displacement, this exaggerates the actual displacement experienced by the lead screw nut.

When is a leadscrew too bent and should be replaced?

If it causes quality issues in your prints.
E.g.:

Mitigation
Buying new, straight leadscrews. Usually, the more straight the more expensive, the lead screws from the far East range from acceptable to unusable. Ball screws are much more precise, but also cost more, especially the ground screws.
Some people straighten the lead screws, there are videos to be found how you do that.
But, note that there is an option not to replace the screws!
E.g., to completely remove any wobble of the lead screw, you can use something called an Oldham coupler to decouple the X-Y movement from the Z movement. For Creality Ender printers, there are specific couplers to order to install so that you will not need to buy new lead screws.
Custom printer designed Oldham couplers look similar to:

There are also printable versions that work very well, in fact I designed and used my own, inspired by this design:

I took a deep dive in Oldham couplers, never heard of them. Absolutely incredible material online: http://vlabs.iitkgp.ac.in/mr/exp6/index.html. Very interesting. I think I found one that takes out Z-wobbling in any direction including tilting, the WobbelX, do you have any experience with that particular one? https://www.youtube.com/watch?v=4kQZnSzZHD0 and https://www.reddit.com/r/ender3v2/comments/14h69g1/wobblex/.

@BobOrtiz Sorry, no I don't.


text:
Extruder feed tube
I have two 3D printers which both have filament feeder tubes that run from the extruder to the nozzle, as usual. But both feeder tubes are very opaque and it is very difficult if not impossible to see where a break is when the filament breaks inside the tube. My question is why aren't the feeder tubes made completely clear, so that one can get a good look at a break and its location. This would be helpful when hot swapping a new filament into the tube. And if there is no reason for the tubes to be opaque, could I change out the opaque tubes and replace them with common clear tubes of my own, or are these tubes special in some way?

Welcome. Please reflect your question in the title. I think you mean 'Why are Bowden tubes opaque and not clear?'. Bowden tubes are made of PTFE and have very low friction.

Ultimaker uses a different material, which is more clear. I've printed many kilometers and never had it broken in the Bowden tube. Maybe your filament is moist (brittle) or bad quality?

The problem is not that the Bowden tubes are opaque but that your filament is breaking.

Fully clear Bowden tubes are not availeable.
Bowden Tubes are made from PTFE or similar, very low-friction material. PTFE is a milky white in its natural state. You can not make it fully transparent and the Ultimaker Bowden tubes are about as transparent as you can get.
The choice of low-friction material is relevant. As long as you don't use transparent filament in them, one can see the filament through un-colored PTFE well enough to see the position.
Some fully opaque Bowden tubes have an even lower friction than normal PTFE, which can make printing more steady, or allow printing materials that normal PTFE might stick to.


text:
Is there an open, perhaps crowd-sourced dataset of visual (image or video) data of failed and succesful prints?
In addition to this question: Is there a open-source pretrained TensorFlow Lite model for failed print and spaghetti detection? And in preparation of training a lightweight (TensorFlow Lite) model myself, perhaps labeling things with Meta's Segment Anything (SAM). Is there an open, perhaps crowd-sourced dataset of visual (image or video) data of failed and succesful prints?
Similar to, for example Mozilla Common Voice for voice recognition datasets,  Common Crawl for natural language processing (NLP), and Open Images for computer vision (CV).
I would like to contribute to this dataset as well as use it for training an open source model that can run on efficient TPU's like Coral AI for Raspberry Pi, for the purpose of Spaghetti detection, empty bed detection and perhaps for other print defects.


text:
Is there a spaghetti detector available that doesn't limit the cameras framerate and resolution?
I am searching for a spaghetti detector that can pause my printer when spaghetti is detected, especially one that does not limit the framerate and resolution of my cameras, like Obico does. That is basically the reason I don't use Obico because it makes my cameras almost unusable for other purposes.
Also, I rather want a self hosted option without subscription per printer.


text:
Are there any Core Heating Technology (CHT) nozzles available for a stock Ender 3 V2 hotend?
I already switched my standard 0.4 mm nozzle to a standard 0.6 mm nozzle with a huge printing time reduction without losing much detail. I also would like to try using Core Heating Technology (CHT) 0.6 mm nozzle instead, to be able to increase printing speeds and reduce printing time even more.
CNC Kitchen tested the performance with the following results:

I found some E3DV6 CHT nozzles, do they fit on a stock Ender 3 V2 hotend or do I need a specific E3D hotend for that? Or since I don't want to upgrade my hotend, are there MK8 CHT nozzles, or are the sizes the same?

Does this answer your question? What is the functional difference between an e3D-Style nozzle, Makerbot MK8 and M6 Chinesium Nozzles?

@Trish Not really but it's certainly helpful. Thanks for sharing.

The answer from there is "You can always use an e3D v3 CHT to replace a Makerbot Mk6-8 or Creality Mk8,, it will fit in the stock ender3, just have longer threads. Adjust bed as needed."

Doesn't a longer thread affect the compatibility with BLtouch, since the height changes too and the probe length? That question you refered to is more about the 'functional differences of nozzle models' while this one is more about availability and compatibility, specifically for CHT. I think it's somewhat similar but asked and answered from a different perspective and perhaps with a different goal in mind.

The BL Touch  can be readjusted to match the needed height, and indeed should be done whenever you swap nozzles.

The longer thread doesn't impose on the BLTouch, the overall length will. I updated my answer.

To answer the main question, yes there are, the typical Chinese market places are flooded with these nozzles nowadays, these are less well manufactured than the original BondTech CHT MK8 (coated) nozzles you can find in decent 3D printer shops.
Simply search for "CHT MK8 nozzle" and you get a list to order from in various sizes, including the requested 0.6 mm.
Image of a typical cloned MK8 CHT nozzle:

Image of an original E3D v6 CHT nozzle:

Do note the quality differences, the original are superior machines apposed to the clones, look at the pattern of the inner 3 bore holes, the original is much closer together so that the filament flows directly into the 3 holes (almost 1 big hole in fact) whereas for the clones the 3 bore holes are apart causing the filament to hit a wall (center piece) and needs to be diverted to the outer 3 holes.

... E3DV6 CHT nozzles, do they fit on a stock Ender 3 V2 hotend or do I need a specific E3D hotend...

Looking at the dimensions below, you see that the threads are identical (both M6x1), but the overall length is 0.5 mm shorter for the E3D v6, so this should match. This reference tells us that the nozzles are interchangeable:

For the [Creality] MK8 nozzle, it [red. i.e. the E3D v6 nozzle] will be compatible with 3D printers that use [Creality] MK8 hotends. [Creality] MK8 nozzles are incompatible with the V6 ecosystem.

The E3D v6 will work on the MK8 because they are longer from the threads to the base of the hexagonal nut, therefore MK8 will not work in an E3D v6 hotend, they are too short. You cannot screw in the MK8 far enough into E3D v6 far enough, the base of the hexagonal nut will touch the heater block and leaves a space between the nozzle and the heat break. If these aren't sufficiently tightened together, the heat block may leak and the cavity is detrimental for retraction performance.

Information on the dimension of the different nozzles
Creality MK8 dimensions:

E3D v6 dimensions:

So it needs to be a specific MK8 version, not the ED3V6 version in order to fit a stock Ender 3 V2?

Yes and no. Do note that MK8 doesn't say much, there are also (older) nozzles known as MK8 that have a smaller hexagonal diameter. You can order the v6 nozzles to fit your hotend, the genuine CHT nozzles are pretty good. I've updated the answer for you. I hope you understand that you should consider to avoid asking multiple questions in one question. Where I thought that the question was more on availability, it seems more a question of can I use a different nozzle in my hotend? But, keep the questions coming!

CHT is patented. Import could be patent infringement

The difference is more than 0.5 mm. In addition to the thread being slightly longer (I think it's 1.0 not 0.5 mm, looking at those drawings), there's (looks like 1.5 mm) additional clearance between the end of the thread and the back of the nozzle head. This is why MK8 nozzles don't work on V6 hotends - the back of the nozzle head will bottom out against the block before the intended mating surface hits the heatbreak.

@R..GitHubSTOPHELPINGICE updating an old answer for that...

@Trish while the patent itself is a whole other subject: 'The US patent for CHT was seemingly rejected in the US, while E3D opposes the patent in Europe.' - all3dp.com/4/bondtech-cht-e3d-revo-heatcore-clash-on-cht-patent. Although I feel like the original maker should be supported for this, this part does contain a second part that needs to be inserted. Perhaps that's different in patent law too. I think at best it's patent pending currently.

@BobOrtiz Do note the quality differences, the original are superior aposed to the clones, look at the pattern of the inner 3 bore holes, the original is much closer together so that the filament flows directly into the 3 (almost 1 big) holes whereas for the clones the 3 bore holes are apart causing the filament to hit a wall (center piece) and needs to be diverted to the outer 3 holes. Buying original would be my advice, it is worth the expenses.

Creality style "MK8" hotends (including the Ender 3's) can use "MK8" or e3D V6 nozzles.
Bondtech sells genuine CHT in both Creality MK8 and e3D V6 forms. If you prefer matching what your machine has exactly, you can buy that, but it will only work on the Creality-style "MK8" hotends, not anything else. If you buy the e3D V6 version, it will work on your Ender's Creality MK8 hotend and any hotend that's compatible with e3D V6 nozzles.
I've always bought the e3D V6 version for my Ender and it's worked fine.

@Trish: OK I've edited to clarify. Does that help?

almost, missed a few E3Ds^^

@Trish: I left out E3D there because "V6" is often used generically in the industry as a nozzle standard by parties who don't want to deal with trademark issues for putting E3D's name in there, but if you'd rather put it in the answer I don't really care.

the rpoblem is, there's also other v6s out there, and while we know now that it is an e3d v6, it might become forgotten in a year and refer to... some other product


text:
How to check the 'health' of the main board without a thermal camera?
Given that the main board gets warm, potentially wearing out the electronics, how do I check the 'health' of a main board without having a thermal camera?
As I understand it could be most easily spotted using a thermal camera are there other ways of checking the 'health' or 'safety' of the main board?

do you mean detecting burnt out connectors etc?

@Trish yes, and methods of detecting other indicators of potential deterioration.

huh... aside from "Stuff doesn't work" that is, right? (because that is obvious^^)

Yes, more for preventative and maintenance. Such as for example inspecting the board of a second hand printer that works. But to measure, get an idea of the quality or safety and perhaps spot potential failure points or safety issues early.


text:
How to set or retain original object size in photogrammetry scans with apps such as Kiri Engine?
I noticed when scanning objects using photogrammetry or the AI-based Neural Radiance Field (NeRF) in apps such as Kiri Engine that the original size is not retained in the object.
How can I actually retain the original size, or set the proper sizes when or after scanning objects like that? So that, when 3D printed it is the same size as the original?

Reference objects
When scanning something, including a simple reference geometry, such as a cube, is best. This can then be used to scale the final model to the correct size and as a reference for if the item has the correct angles. Besides cubes, coins (esp. matte ones) make handy markers and scale references.
If your scan contains color values, a simple photo scale angle could suffice. That item would be taken directly from photography. There it is sometimes required to contain size information and a pointer to the angle the photo was made at. This is made by using a square or angle with scale markings and distortions of the item can be solved later till the angle appears properly and to the right scale.

Do you know if there is a way to do this automatically? Like select the object and tell the size. I can think of 3D scanning something first. Then make a photo of the object with a reference, use overlay to position but it likely won't be too accurate. What if you want milimeter precision? It's hard to do manually with a reference object.

@BobOrtiz I don'T think Kiri has it, but some scan engines with turntable from about 2020 used a reference item they scanned first before scanning an actual item on the turntable, using the known reference as scale

I have a RevoPoint Inspire with a turntable and 'magic pad' too, I suppose they use those markers as reference too. But so far I absolutely hate using it.


text:
Effect of top thickness on print with bumps on top
My son is printing a simple block with a small (2 mm high) bump on top - see image below of the cross section. The left shows the 3D model and the right shows where the plastic actually prints, using a grid infill at around 10 %, with a top height of 1.6 mm

As you can see, this is very weak, and the bump very easily snaps off, as it has very little plastic securing it to the layer below. When we increase the top/bottom thickness (in Creality Cloud) to 4 mm this issue goes away, and the bumps are well connected. But then the print takes a very long time.
Questions:

Is this the expected behavior of a slicer? Why does it not add material to firmly connect the bump to what is beneath it?

How exactly is the "top thickness" setting applied? E.g. if it's set to 2 mm, does that only apply to the layers comprising the topmost 2 mm of the model, or does it stipulate that there must be 2 mm of plastic at the 'top' of the model at all X, Y coordinates?

Is there a way to set the top thickness separately from the bottom thickness in Creality Cloud?

Welcome @tom, please consider splitting this question into multiple questions and reflecting the main question in the title of your post.

@BobOrtiz I think this is one well formed row of questions.

Modern versions of Cura have a feature called "skin edge support thickness" which will build extra perimeter-like layers under the edge of your "bump" down into the infill area, making it attach much better. I believe it defaults to on.
Your problem is probably that "Creality Cloud" is based on an ancient fork of Cura and does not do this, but you could check and see if they have anything similar available. The right solution, though, is to use real up-to-date slicing software like recent Cura (5.x at the time of this writing; I believe the feature was introduced near the end of the 4.x series), PrusaSlicer, or anything but the junk your printer vendor ships (or doesn't even ship but expects you to interface with via the cloud?)

Great - thanks, sounds like Cura is the answer! (to complicate matters, Linux support is not available on Chromebooks using Google Supervised Account (Family Link), so now I have to find a different place to install Cura, oh well. Thanks again!

Is it expected?
So you want to print a block with nubs.

Putting it into the slicer, and looking at the first layer of the top, you will see that there is a an empty hole that has the diameter of the nub's outer diameter minus the wall thickness, where only the infill is. A little bit further up, one layer over the top layer, it's easy to see that the whole nub is resting on just its wall, which is filled under it.

This means, the contact area between the nub and block is very limited: it's only the walls, and a little bit of squishy infill.
What are top layers?
The top layers are a number of layers that are directly under any surface that is defined as having a normal vector that is pointing "up". In our example, there are two: the circle from the nub, and the block without that circle.
Why does it work with super thick top layers?
Remember what I said earlier about contact area of the nub to the nub? If the nub is lower than the height of the number of top layers specified, the whole nub is solid, and any top layers that are still remaining get resolved to completing the top layer of the block. From the bottom there still is a bore, but the interface between the nub and the block is over the full area of the print. As adhesion goes with the contact area, that means the nub is more resiliant.
But as you print much more plastic, you also print much longer.

Is there another way?
In some slicers, you can modify the print behavior in specific parts of the print and define a different infill.
One such example is Ultimaker Cura, you could insert a (floating) cube at the interface between the block and nub, intersecting both for at least two layers, and declare that cube a print-setting modifier. Then you declare that cube to be printed with 100% infill, and you get the large interface area between the two parts and at the same time keep more of the model hollow than with many more top layers.

Thanks for the detailed answer and those wonderful images (Creality Cloud does have that much detail). We'll switch to Cura!

@tom oh, those snippets are from Cura 5.x - orange is infil, yellow is layers, green is inner walls, red is outer wall

looking forward to getting Cura 5.x then !


text:
How can I improve print speed with carbon fiber nylon and an 0.4 mm nozzle?
I have been trying to print fiber-filled nylons (Polymaker PA6GF and Taulman PA CF) on my Prusa i3 MK3S+ with a steel E3D 0.4 mm nozzle at a reasonable speed. I print at 290 °C for the Polymaker and 265 °C for the Taulman. This is at the upper end of the specified print temperature range. I can only print up to 25 mm/s before the extruder gears slip and never regain traction. They are tightened pretty much all the way (not that it makes much of a difference). Can the print speed be improved somehow without moving to a larger nozzle, or is this the limit? I was thinking a bimetal nozzle or maybe even a volcano-length nozzle with nuts might improve the viscosity. I would like to get up to maybe 50 mm/s.

I emailed polymaker and the rep said a volcano style hotend should help. I ordered a plated copper melt zone extender to try out as I don't have a standard volcano heater block.

I got a nickel plated copper meltzone extender which solved the problem. I was able to print a decent benchy with the fastest print speeds at 70 mm/s. The melt zone extender results in the same melt zone length as a volcano nozzle in a normal v6 heater block. A volcano nozzle with an adapter or just a couple m6 brass nuts should work the same. I got the Polymaker filament to work but not the Taulman. I would avoid it.