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How to determine width of the nozzle, that is already installed on the printer?
I have a 3D printer, which wasn't used for a longer time. There is a nozzle, but don't know what diameter is it. I used several widths - from 0.2 to 0.8, switched them depending on my needs, but don't remember which one was used lately.
The nozzle is a little bit worn down, so the diameter on the side is not visible.
How to get the nozzle diameter, without taking it off the printer?
This is more of a theoretical question, because I can simply swap the nozzle, but still - eager to know.

Have you seen this question, the answers may help you, the question is very similar.

Does this answer your question? How to measure the nozzle diameter?

I can't see how your question differs from How to measure the nozzle diameter?

The best method is to have a scale on your microscope that looks like a ruler drawn in the optical path.  However I usually visually compare an unknown nozzle with known nozzles under a microscope.  If you don't have a microscope, you can get USB otoscope cameras (15mm focal length for looking in ears) for under $20.
You can get a fairly good idea of the size by telling the printer to extrude in air then measure the extrusion diameter with calipers.  Of course, it's better if you can compare with a known nozzle.  If you push the filament through by hand, the extrusion will be too thick.  With the stepper motor extruding, I measure the extrusion diameters between 0.3 and 0.5 mm on a 0.4 mm nozzle.  Low cost calipers are less than $20.  The main different with the low cost calipers is the slides are not smooth, reducing the accuracy in the 0.01 mm place.

If your nozzle is worn enough that you can't read the size stamped on one of the hex flats, you need to replace it anyway.
That said, the best ways I know to measure the aperture are with either a pin gage (known diameter high precision wire, find the largest that will enter the nozzle aperture), or optically -- take off the nozzle or hot end and put it on a scanner bed; use the scanner to image the nozzle at highest available resolution, then count the pixels across the opening in the image and multiply by the pixel size (for instance, if 6400 ppi, you'd multiply your pixel count by 1/6400 in/px * 25.4 mm/in).
I've used the optical method to measure photographic pinholes (drilled in delicate, .001" thick brass shim stock) that were smaller than 0.5 mm, so I know it works in this size range.
Measuring the extruded filament may not give an accurate diameter, for two reasons -- the hot, freshly extruded material may either swell or stretch after extrusion (and may well do both in a short length of extrusion, giving varying diameter), and it's difficult to accurately measure small round samples (especially of plastic) with either micrometer or dial/digital caliper -- it's too easy to compress the sample and obtain an artificially undersize result.

I got interested in the question and did some research. I found PCB drill bits from 0.1-1 mm in 0.1 mm steps for around 7€ and believe they are an interesting option. They should help clean the nozzle (or quickly break in the process?) and I think one could experiment with revitalizing worn nozzles by drilling them up a bit (as they are carbide, they should work well with brass nozzle, hardened steel ones might be too much). Having them (and a Dremel-style tool and proper clamping) could open up a world of nozzle hacking, see e.g. CNC Kitchen on YouTube for what happens if you solder a copper wire into the nozzle.

I would find some wires (piano wire, CAT5 copper, paperclip, nozzle unclogger, etc. ) and choose one that should fit the nozzle (eg. a 0.5 mm copper wire will fit a 0.8 mm nozzle) and push them into the nozzle. Heat them up a bit to soften the filament in the nozzle and brush with a metal wire brush to easily clean it up.

This would seem to be a logical answer, and I was thinking along the same lines, using either wire or fishing line. However, as you mention, apparently a 0.8 mm wire wouldn't fit a 0.8 mm nozzle - so it would seem to be a bit of a hit and miss measurement, unfortunately. Unless you have a table showing which wire diameters fit which nozzle diameter. Also, the wire would probably need to be manufactured to a pretty high tolerance, for it to be accurate.

A .8 wire would fit a .8 nozzle just fine and will absolutely not fit in a .7 nozzle. The wire should be filed to a nice round edge and not a rough cut.

This answer seems to be about cleaning the nozzle, but the question is about measuring its aperture.

Unwound guitar strings are good for poking out the nozzle. Take a set of “10’s” the most common size for electric guitar, the high E string is .25mm, the B string is .33mm, and the G string is .43mm. Acoustic guitar strings are a little larger as a set.

Extrude some filament, let it hit the desk or whatever surface the printer is resting on; but not the bed as it may be too close. The initial filament will form a coil. After extrusion stops measure the straight part of the extruded filament as close to the coil as possible. This will give you the true current nozzle diameter. (Edit: I mean measure with a micrometer)
Just as ancillary info, the nozzle diameter increases as the filament is passed through it. This is called nozzle wear, and since the diameter is changing the quality of your prints is going to drift. If you have a brass nozzle then after every spool of filament, you should reverify your nozzle diameter. Steel or other hardened nozzles would be much more resilient.

This doesn't account for die swell.

@Davo, from what I understand Die swell in as it pertains to a 3d printing nozzle would not make a substantial difference during the extrusion and printing process.

Not every material suffers from die swell, it's material dependent. And it tends to be minimal if extrusion is slow.

Majority of nozzles have a .4 or a .3 on it, that indicates how big it is in millimeters. If yours doesn't, take one of these digital rulers (the ones that have the prongs that stick out on the side and slides, I don't know the name off of the top of my head), extrude some filament and measure the filament, make sure that you find a piece that was extruded after the bottom hit the ground and make sure that you find one that isn't bending that way its not stretched or compressed.  (Your measurements won't be exact due to things cooling off and shrinking)

The word you're looking for is calipers.

I might be wrong, but wouldn't the extruded filament be wider than the nozzle (after heating and deformation)?

I believe that it would actually do the opposite @Greenonline because heat makes things expand so when they cool off they would be shrinking.


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What is average price for 3D parabola?
So I wanted to print a 3D parabola, with a radius of 15 cm and a height of 4 cm.  I've told this company, they told me that they need 3.5 days and its price will be 147 USA dollars and 50 cents.
I just want to know what is the average price for this?

What material is this to be printed in? Are you supplying the model or is the company creating the model? There are other variables to consider to be able to supply a sufficient answer.

company created model itself

As a "Math boy" you would expect you do the math . If it is a plastic model, slice the model, note the filament length needed and deduce how many is on a spool at what price and add some extra for your time, energy and depreciation charge of the printer. I am guessing the object to be printed is in metal considering the price. This question is unanswerable without more details, please supply details by [edit]. Thanks.

0scar, you have listed T&M costs only. Of course the designer's work adds to this. And note company overheads (like premises, management, communications, ...), and packaging, shipping, payment handling, and the taxes. Thus it would be cheaper when ordered on bulk ;)

Normally one thinks of a parabola as 2D. Are you thinking of the shape of a parabolic mirror on a reflecting telescope?

Maybe you are asking for a very smooth and accurate print.  They may be planning on a 0.1 mm step size with a 0.2 mm nozzle.  The model may also have smaller line segments than the default for the slicer.

Isn't the term for a '3D parabola' a 'paraboloid'?

The price dependss roughly on material, machine hours, operator labour, profit and administrative overhead.
Some companies deduce the operator labour, machine hours and overhead to roughly 10 times the material cost. I think that is kind of fair. In your case I assume that you use PLA, the perabola is hollow (just a flat surface) and the company needs to construct the 3D model the parabola to a specific tolerance.
this model in PLA should not cost more than \$5 in filament, so about $ 50 should be an okay price for your parabola. The total price of \$147 leaves about \$97 for modeling the parabola. I think that's fair, given that a non-mathician has to find a way to construct a model and test the results.
If, for example, you want a metal print and you provide the 3D model I find the price of \$147 to be very normal. These metal printers are very expensive, labour intensive and eat up energy.
You can get instant quotes at the following sites: https://xometry.eu/, https://formalize-am.com/
All above is just my best guess, given the data you provided. Expect a better answer when you provide more data.

yeah company told me that they use PLA, is there any cheaper material?

Not really. PLA is about the cheapest stuff you could get. But the material is not the most expensive. having someone do the labour is the expensive part. Still assuming you have to get the parabole modeled by someone, you could try to find an online mathematical model generator or download a parabola from Thingiverse. Some models are in openscad, where you can easily code a math shape. If you'd live in the EU I could help you out printing it.

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Hotend is oozing out the sides and getting in the way of my print
My Ender 3 just started having this problem a couple of months ago. Prior to that the amount of excess filament showing up on the hotend was very minimal, but now it is oozing so much out of the top of the metal hotend, that it is hardening on my prints and hitting my extruder. How did this happen? and what can I do to fix this problem?
This is the hotend I have, a detailed image of my hotend is shown below:

The part of the hotend that I think is oozing is highlighted in purple/blue.
Here is the actual Image

There is now a clog somewhere, since I changed the filament yesterday, not sure if that is related, just thought I should mention it.
UPDATE: I fixed the clog, and it is not related to the hotend...

Can you supply a picture so we can see exactly what is happening? This will help in being able to give you the best solution possible.

Do you have a motor (pushing the filament) attached to the heat sink or do you have a Bowden tub attached to it?

@PerryWebb I have a filament extruder, attached to a tube, that is attached to the filament hotend.

I know it's a little late... but... this specific problem seems to be common with thread in tips and heat break tubes. E3D's heads have it too.
The source of frustration is there are 3 dissimilar metals that all thread together, all have different thermal coefficients of expansion, so with heating and cooling cycles there is "crawling" of the parts and gaps widen.
Common wisdom is to "assemble everything hot" so you are at max metal expansion before tightening things down. I have only limited success doing this.
If I ever find a better solution, I will post it.

Looking at the picture of your nozzle, it appears to seal against the heat break and not the Bowden tube.  (A nozzle sealing against the heat break will have an entry hole of about 2 mm dia. for 1.75 mm filament.  A nozzle will have an opening large enough for the Bowden tube to slip into if it seals against the Bowden tube.)
If your heat break is all metal, you have an all metal hot end that can extrude above 250 °C.  If your heat break has a Teflon tube inside it, your hot has a highest temperature below 250 °C to avoid degrading the Teflon.  Both follow the same procedure below, but you highest temperature for making the seal will be different.
To see if your nozzle is OK (not clogged), try pulling the filament out with the hot end at temperature (same procedure as unloading filament).  Trim the irregularities off the filament while leaving a sharp end.  Then, see if you can push the filament through the nozzle at extrusion temperature.
If still clogged, remove the nozzle (you will need to tighten it later anyway) and see if the filament will go through without the nozzle.
After camera piture: unless your hot end is all metal, the Bowden tube likely forms the seal to the nozzle.  See if the length of the tube going into the hotend goes down to the nozzle.  The end of the tube needs to be smooth to make the seal and the seal surface to the nozzle needs to be clean or the filament material soft enough to push out of the way.  Pull up to release the tube.  When you push down to lock the tube in, it should push the tube against the nozzle.
For an all metal hot end follow the procedure below.
Before camera picture:
Sounds like you lost the seal between the nozzle and the heat break.  For most hotends (unless you have a plastic tube that pushes up against the nozzle) heat up to the maximum hotend temperature, then tighten the nozzle tight against the heat break in the heat block, to form a seal between the two.
If the nozzle tightens against the heat block before the heat break, you won't get a seal.  You should see some threads of the nozzle exposed and not in the heat block.
Take care not to over tighten the heat break in the heat sink because the heat break is thin going into the heat sink to minimize heat conduction and will easily break.
If your seal to the nozzle is with a plastic tube, investigate why you don't have a seal.
Looking at picture:
Follow the above procedure while the heat break to the heat sink is of less consern since it appears that separate screws tighten it into the heat sink.

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How do you adjust for elevation and layers not sticking together?
My printer was working fine two weeks ago, I traveled cross country with it (making sure it was secure while moving) to a place of significantly lower elevation. Nothing has printed well since I got here, including the print I did two weeks ago (same settings). I've adjusted flow rate, extruder temperature, infill density and style, fan settings, and releveled the bed, and I still have really brittle layers that don't hold together. It's almost like the nozzle is moving up and down on each layer in a pattern.

Hi, welcome to 3DPrinting.SE! An image of your printed objects would help a lot.

What type of bed do you have ?

What material are you printing?  Do you have a printer model?

Are the thermistors measuring temperature correctly.


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Insulating bed material?
I've observed printing PETG that the primary if not the only reason for using a high bed temperature seems to be preventing the bed from acting as a huge heat sink and rapidly cooling the initial layers such that they don't bond well to each other. In particulat, the heat is not needed for adhesion-to-the-bed purposes. This got me thinking whether there's a way we could get rid of the requirement, as a way to save time and all the energy spent heating the bed and cooling the room it's eventually dumped into.
With that in mind, are there viable bed materials that are good thermal insulators? Just putting down a layer of any insulating material between the underlying bed and buildtak or whatever surface you want might work, but I would think these kinds of print surfaces are designed for moderate to high thermal conductivity themselves, and wouldn't be as bad a heat sink as the underlying metal, but might still sap a noticable amount of heat out of the part right away.

glass/tile beds might be nice specifically because of this.

You can place a 2-4 mm thick MDF board on the bed and print directly on it, or you can place a 2 mm thick cork foil (IKEA office desk supplies) between magnetic plate and aluminium heater. The magnetic plate should not absorb too much heat and the cork will avoid conduction to the aluminium heater.
If you want to avoid the magnetic plate, print on paper/cardboard on top of cork.

Very early (pre-RepRap) commercial 3D printers used foam build plates. They were single-use as the foam would be damaged when removing the print, but it's probably as insulating as you can get.
This blog post details some experiments on using foam as a build plate and mentions a particular type of foam that is apparently most suitable.


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Edit G-code to change print order of multiple one-at-a-time print jobs
SUMMARY: I use a Creality Ender 3 and Cura 4.8 slicer. I need to print multiple objects 'one-at-a-time' (Cura allows this, that is fine) and I must specify the order in which each model is printed but Cura does not have this facility. My question is: how can I change the order of the printed objects by editing the G-code?
DETAIL: Sometimes it is essential or useful to specify the order of printing multiple objects in a 'one-at-a-time' batch print to allow the printing of some objects that are taller than the X-gantry clearance together with other objects that are shorter than the gantry because if you can control the order then you can print the small objects first and then the tall objects (because the gantry won't get in the way of the already-printed small objects but if the tall objects are printed first then the gantry will crash into them). Specifically I am talking about two or more objects printed at roughly the same Y-level on the print bed (I know you can 'get-away' with it if you separate them in Y but I want to print multiple rows of such objects). Without control over print order this cannot be done thereby limiting productivity (number of models per print run).
WHAT HAVE I DONE TO RESOLVE THIS ALREADY: I can control the print order of multiple identical objects in Cura (they are printed in reverse order to their creation as duplicates of an initial model and if there are problems you can sometimes control the order by moving objects around) but this does not work for multiple different objects. I did several Google searches and found some conversations that deal with this issue including on the official GitHub page of the Cura slicer (see for example this Cura GitHub Discussion). The conclusion given by the Cura developers is that they understand the limitation, but it is not an issue for Ultimaker printers so they have no plans to make user-customisable print order a feature in Cura because it would be too much work for them to do the changes and maintain them. One person mentioned a python script to allow post editing of G-code to change print order but I could find no links to it. Another person described a 'workaround' in Cura to do with grouping and ungrouping models in a specific sequence but this does not work for me (?maybe it only worked in older versions of Cura). Perhaps someone on this forum has G-coding knowledge and could shed some light on how it may be done? [PS: I am only interested in G-code editing solutions for this question, or a Cura workaround that works in v4.8 - I don't use Octoprint/Rasperry Pi controllers].
Thanks.
[EDIT] Thanks to the contributors in the accepted answer I managed to do this with 'cut-and-paste' (via a small C program - you could do it manually but it is tedious and there is more risk of making a mistake if you have many models). I used the comments in Cura's G-code and a few other G-code cues to calculate the correct splice points.
It works provided you take care to ensure the new extruder code is either altered according to the new model positions or use the 'relative extrusion' mode when saving the original G-code from Cura (I used the latter method). Also you must splice the G-code at the right points to ensure pre-model start and post-model finish G-code commands are properly carried around and the final model in the original G-code needs a terminal G0 command to be constructed if it is no longer terminal in the new order so that it can properly position the nozzle to go to the next model in the chain. Also you need to ensure M107 is included prior to each model's first layer. There is danger in doing any of this - the new G-code might damage your printer if you get anything wrong - but it can work (at least it has for me).
I made several manual checks on the new re-arranged G-code as well as loading it into Cura and running Cura's nozzle simulator on it to ensure it does what I expected of it prior to risking running it in my printer, but after that it printed OK.

This would suggest a useful feature request to forward to the Cura development team, assuming it isn't already in 4.9...

@ZeissIkon The Cura developers know that people want this feature but they don't want to do it. It is potentially dangerous but then messing about with Cura settings (overriding machine defaults for your printer, etc.) is similarly dangerous. As long as people know that and accept the risk then that's fine I think. If there is enough demand then perhaps if I can get my code into a form others can easily use I will post it on GitHub - with a big health warning!

Seems obvious that you'd want/need to make the shorter parts first, even if they're spread to the corners of the bed.  If they're spread enough, on the other hand, it doesn't matter as long as none of them are high enough to interfere with the gantry and they're far enough apart not to hit the hot end fan cases etc.

You can open the G-code file in any text editor and copy-paste the relevant sections of G-code to reorder them. It will be fairly obvious where one object ends and the next one starts because the printhead will move back down to Z=0; you can do a simple search to find the commands that move to Z=0 (in my version of Cura, it inserts a comment ;LAYER:0 at the start of each object).
To ensure that the extruder starts in the correct position, look back at the previous print (in the original order) to see where the extruder finished, then insert (at the start of the new print) G92 Exx.xx where xx.xx is the previous position of the extruder. If looking back to the previous print is too tedious, you can also just use the very first extruder position in the print itself and use that. It will just skip printing the very first section of brim/skirt, which doesn't make a big difference.

Unfortunately it is not that simple. The position of the extruder progresses from model to model in the original print order - and it is cumulative. So the first model E starts at 0. The second model E starts at (let's say) 23.214 mm because that's how much filament has been extruded so far for your first model. If you just swap them around with cut and paste then the printer will spew forth 23.214 mm of filament before starting your first print then, when it gets to the second one it will retract back to E=0 sucking up air all the way and your second print will be made of thin air.

@WildCat Good point. You can just use G92 to fix that.

@WildCat The G92 command really does fix that issue. You don't need to (programatically) change all of the E position commands. Using G92 tells the printer that it should "virtually" move the extruder, that is, not physically move it but only update the printer's memory to set the extruder to that position. For example (if the starting position is zero) issuing G92 E10 followed by G1 E20 results in 10mm of filament being extruded, the same as if we had just issued G1 E10.

OK. My apologies - I didn't fully appreciate the meaning of G92. That would make it a lot easier to re-jig the code with simple cut-paste style re-ordering. It would still help to have a program to do this for many prints on a plate but that should be a lot easier to write. I will experiment a bit to make sure it works in practice before accepting your answer (although if someone could point to a free tool that already does this, that would be even better).

Switching slicer to relative extrusion mode might be an easier option.

@R.. GitHub STOP HELPING ICE Thanks.That does make it a bit easier (less work) to algorithmically recognise the retraction that occurs prior to each new model starting but I wonder why Cura warns of 'extruding slightly less plastic' with relative mode as the E differences appear to be the same to me on inspection (between absolute and relative modes). They also warn that not all printers are compatible but that's not a problem as one can always convert back to absolute mode using the G92 command in the post edited G-code and removing the relative mode once models have been re-arranged.

@WildCat: It's a matter of cumulative floating point inaccuracy in letting the printer's firmware sum up the the decimal values printed in the g-code, which are each individually inexact, vs getting a new position value from the slicer that gets rounded to the nearest representable value on each move. This is a real mathematical issue, but the order of magnitude of the error is likely much smaller than the error on calibration of your e-steps or filament diameter, so in practice I think it's a non-issue.

Exactly. For absolute E values, find the E value for the last print move of object 1 and edit it into a G92 at the beginning of object 2, etc. Then, when you reorder, the values will start at the proper number for each object.


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Is there lead in brass 3D printer nozzles?
I was just wondering whether or not there is lead in brass 3D printer nozzles as I read that they do add lead when making brass to improve reliabilty or something along those lines?
I was curious as to whether the same reason applies to 3D printer nozzles and if it is enough to warrant buying a steel nozzle instead?

It would probably depend on the individual manufacturer as to the amount of lead in the nozzle. IIRC, Steel nozzles are implemented whenever you have a material that requires a higher temperature that is too much for brass.

Lead is added to brass to improve its machinability. (Arsenic is added to improve corrosion-resistance.) I imagine that the factories making the nozzles would opt for easier machinabilty, but you could buy lead-free brass and pay a small machine shop to make you some nozzles.

@Andrew Morton Would it be enough to cause any significant damage if ingested, say after swapping out the nozzle and then eating?

@JamesM I'm not qualified to answer that, but you should always wash your hands after using machinery anyway. And before preparing food/eating. I don't know what's in the grease on the printer and you might not notice that some had got onto your fingers, so there's that to consider too.

Amalgam, a silver-mercury alloy is generally a safe filling for teeth unless it is exposed to some chemicals or cut into. The Removal of them uses heat, which breaks the alloy down and creates mercury vapor. However, as long as it is handled properly, the material doesn't add mercury to the body from contact alone.

It should be noted that there also exist several lead-containing alloys of free-machining steel so going with wear resistant non-brass nozzles does not preclude the presence of small amounts of lead.  All the reasons for choosing free-machining brass for the manufacture of nozzles apply even more so for making steel nozzles. Drilling tiny holes in steel is a more challenging machining operation than doing so in brass.

It's very likely that leaded brass is used in the manufacture of nozzles for 3D printers -- as noted by @AndrewMorton, this is done to improve machinability (the same is true of some steels, by the way) -- and when you're going to have to drill a hole potentially as small as 0.1 mm diameter, you want all the machinability you can get (I can say from experience that brass without the lead is very annoying to machine and likely to produce unacceptably high rates of broken tools and destroyed parts during that drilling operation).
That said, the amount of lead found in a single nozzle is very small, generally between 1.5% and 2.5% by mass -- a typical nozzle is only a few grams, so the lead content would be a few tens of milligrams.  Further, ingested lead (as metal) is not a major toxicity issue, because stomach acid reacts to form insoluble lead chloride, which then passes through the gut almost unchanged (some lead will still be absorbed, but swallowing a whole lead bullet raises bodily lead loading less than breathing in a shooting range for an hour or two each week for a year, where lead compounds float in the air as smoke, both from primers and from unjacketed lead bullets).
If you, a child, or a pet ingested a used nozzle (say, you dropped it and couldn't find it and worry about your dog), it would be more likely to do harm by abrading the intestinal lining as it passes than by the toxicity of the tiny amount of lead in the metal.  If this is a "today or yesterday" event, you should promptly consult an appropriate health care professional (physician, pediatrician, or veterinarian), who will likely want to take x-rays or CT scans to ensure the item passes through the gut rather than lodging somewhere along the way, as well as monitoring for symptoms of a complication (a perforated intestine is life-threatening, but relatively easy to repair if caught promptly; the surgery needed is similar to an appendectomy).


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Help With PLA settings
I’m just getting my feet wet with 3D printing, and I’ve had a few prints do this. Curious if anyone has any ideas for me that might help clean this up? (I don’t really have anyone in my personal circle who can help out, so hoping this community can :) )
Edit 5/23
The first layer of the print is inconsistent in the way it’s deposited. Some areas feel correct while others are very thin. Usually there are large gaps like in the pictures below. After the first layer, the rest of the print seems to be fine. I’m curious is anyone has any insight into what could be causing the inconsistency.
I try to level the bed before each print, but I’m not sure if it’s at the correct height as the instructions I got with the printer are pretty subjective: “use a piece of A4 paper and you should be able to pull it with some resistance”.

Hi and welcome to SE.3DP. Whilst the photos are great, and a picture is worth a thousand words (etc.), could you [edit] your question and describe what is wrong with the print? In particular, what are the series (or areas) of small lumps in the center? Are they gouges in the print?

@Greenonline thank you for your input. I’ve updated the question, please let me know if that looks better.

Much better, many thanks... WRT the paper, some resistance means barely perceptible, not that it is a struggle to pull the paper through.

It looks like your nozzle is a little too close to the bed, if there is not enough space, you can see through the layer and pressure can build up and ooze out when there is a little more room in a different location (if the bed isn't completely flat/straight).
You could level with a thicker piece of paper or add a Z-offset to the whole print ( e.g. in your slicer, or change the G-code by redefining the Z height).
You could also increase the first layer a little when slicing.

Thanks again @Oscar. It was a combination of poor leveling on my part and having the extrusion force too low. Adjusting both of them seem to be producing higher quality prints for me.

It looks like a bed adhesion problem to me. Some additive information: What is your bed material?
Z-calibration problem isn't the only suspect. I've seen the same problem with my printer before. There were defects in some parts of my glass print bed that prevented it from sticking.
The molten filament from the hot nozzle has two adhesion chances; full adhesion to the bed or adhesion next to the previous extruded filament. If the previous filament is not stuck to the bed, it means you are printing on the air shown in the pictures.
Without forgetting, your images also seem to have a Z-calibration problem, but as I said, I don't think it's the only suspect for blobs. It will be useful to clean the surface.

Thanks for your input. It was a combo of the z-axis height and the extrusion force. I can see how my magnetic mat might need to be cleaned soon as well as it’s getting messy with remnants of old prints.

Yes, extrusion force could be another story about the nonstick problem.


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How can I print in multicolor with Ender 6?
I'd like to make multicolor printing on Ender 6, but it seems that the filament change (ADVANCED_PAUSE_FEATURE) doesn't work (it works on my Ender 3).
Can you help me how can I solve that? How can I make the ADVANCED_PAUSE_FEATURE available on Ender 6?

Enabling ADVANCED_PAUSE_FEATURE requires a rebuild and upload/install of a new Marlin firmware. The option is found in the advanced configuration file (Configuration_adv.h).
Please change:
//#define ADVANCED_PAUSE_FEATURE

to:
#define ADVANCED_PAUSE_FEATURE

Rebuild and install the firmware.


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Does shimming my build surface compete with spending a bunch more money and time on an auto-leveling system?
I've had my Ender 3 for almost three weeks, gone through about a kilogram of PLA filament (printing a mix of upgrade parts for the Ender 3 and stuff I actually want to use) and made one PETG object, generally with good results.
I've noticed however, as seems relatively common (per YouTubers, anyway), that my bed isn't flat -- that is, the build surface isn't a good approximation of a geometric plane.  If I adjust the bed to have correct clearance (good adhesion and correct single-line width) at the corners, I'll get adhesion failure in the center, and if I adjust to give a correct center, the extruded filament will be squished into the build surface texture; the nozzle may even lightly scatch the surface at the corners.  That indicates the corners are high, relative to the center, by roundly 0.1 to 0.15 mm.
I'm aware of BLTouch and its clones, but in order to get full use of that system (which automatically compensates for the non-planar bed) I would need to not only install the surface sensing hardware, but flash my printer's firmware (potentially after removing the control module cover and plugging a cable and adapter into the mainboard).  As a longtime builder/upgrader of my own computers, this is certainly within my capability, but I'd prefer to make my build surface flat instead of applying software corrections; I see this as upgrading from a 386 to a Core i3 because the computer is overheating -- that is, the problem will go away because of all the other stuff you have to do, but you haven't really solved the problem.
My general idea more or less mimics the self-answer on this question in terms of measuring the excursion and applying shims under the build surface (I've installed the Creality magnetic sheet surface, so shims would be applied between the magnetic base sheet and the removable build surface).  I plan to use household aluminum foil, standard weight, which is generally close to 0.63 mil (= .016 mm), applied with repositionable spray adhesive and laid down in layers, using a combination of feeler gages and single-layer test prints to determine where and how much foil to apply.
I've "test flown" this option by putting a single Post-It sheet under the center of the removable build surface, and now I have a much closer match between the center and corners, and can (depending on my nozzle standoff) actually see the outline of the makeshift shim in the first layer where it prints over the edges of the Post-It.
Is there anything I'm missing that would prevent this shimming method using aluminum foil from resolving the warped bed to allow me to depend on an even thickness and correctly adhered first layer?

foil would block the magnet, which might cause an issue if you had larger areas. it also expands more than magnet stuff by heat, which ain't great.  plastic (electrical) or paper (masking) tape would be  better for those two reasons, and easier since they self-adhere.

if you can get away with not leveling, that's far preferable, no matter how automatic it is, it still wastes your time. I haven't re-leveled my CR10 since last year, so a BL-touch is a huge waste of time and effort and complications for me personally.

@dandavis Have you tried this?  It's been my experience that aluminum foil passes magnetic fields as if not there, unless it's moving relative to the field.  https://4emi.com/emi-shielding/shielding-actually-works-filtering-best/#:~:text=Most%20conductive%20materials%20such%20as,steel%20provide%20substantial%20electric%20shielding.&text=Unfortunately%2C%20aluminum%20foil%20is%20extremely,material%20provides%20more%20adequate%20shielding.

There is a 3rd option, manual mesh leveling, which Marlin firmware can do. Instead of using a sensor each print to probe the bed, there is a routine you do once by hand and you save it in the printers memory. Then each print you use a G-code command (like in the print start G-code that gets added to every print) to load the mesh from memory.
I haven’t done it myself, but as I understand you heat the bed, then do a routine going to the probe spots on the bed, and use micro-stepping to adjust the Z height at each point, using a feeler gauge/paper to dial in the nozzle height.

@ChinchillaWafers Just to make this odder, the Post-It I had under the center of the magnetic mat was too thick, so I pulled it out -- and now the bed is acting flat, to better than 0.1 mm anyway.  I wonder if I might have been trying to level when the bed wasn't fully temperature stable -- lots of stuff will warp while heating, and smooth out once it's equalized (telescope mirrors are famous for this).  If I don't see a good answer before I have time, I'll write this up as a self-answer.

I've ordered a polymer coated (sticky when hot, releases when cool) build surface plate.  Not sure it'll flatten the bed warp of 0.1-0.2 mm, but if it doesn't, it'll make it easier to shim flat (because it'll bridge the edge of a shim instead of leaving a step in the surface).

Shimming is fine. And 386 were basically never overheating.

@FarO Which was pretty much my point -- why upgrade something that doesn't need it, when the upgrade isn't fixing the actual problem?

I may be biased as my question/answer is the one I believe you're asking this question in reference to, but I would say that yes, it not only competes but is a far better solution. "Auto-leveling" systems do not level your bed. They just partially compensate for poor adhesion by adjusting the bottom layer(s) of your print to conform to the bed's errors. This of course messes up the dimensional accuracy of your prints; in a worst case it can come out rather absurd. They also do not compensate for the change in volume (which would require differing extrusion amounts) due to changes in Z height to compensate for the non-level bed.
The right solution is always to get your bed level and flat. Ideally if the bed/print surface is warped, you replace it with one that's not, but shimming is a reasonable alternative. ABL systems (not talking about real 3-point leveling with 3 Z motors here, but "ABL" stuff like BLTouch) are a gimmick for making it easy for beginners to start printing without all their prints failing due to non-adhesion from poor manual leveling. They're not a solution.

So, the difference between the shimming vs. auto-leveling is that auto-leveling goes around in a 4x4 grid taking measurements of the bed (you do need to set the Z calibration first, as you know) vs. the shimming method where you go to 4 corners on your build plate where you stick a piece of paper or something under there and you adjust the knob at the bottom until you can feel tension on it. What I've found to be the best for me at least is to use both. This is my method for printing every time:

Clean the build plate. I will take my scrapper and scrape everything off, then I will run it under some hot water and wipe all of the residue off that is still remaining, then I might take some glass cleaner or something and wipe it down.

Set the Z calibration.

Do the shimming leveling (I would normally go through all of the corners again plus the center/Z calibration just to make sure that I didn't mess up any of the other corners.

I will run the auto-calibration (I use OctoPrint so I just run it through there)

Smear Elmer's glue over the print bed. I do this for a couple of reasons:

I use the glass side of the bed, just because I've gotten better results this way, and
it just makes your prints stick better. I also do this after the Z calibration and bed calibration because you get better results this way.

Start the print and watch the first couple of layers. If you notice that when you are printing and the brim looks stringy, like you could pick apart the individual lines, you should cancel the print, and go back to your slicer and bring your line width down my 0.1 mm, I typical print with the lines 0.1 mm or 0.2 mm below what the nozzle prints at, so a 0.5 mm nozzle I will print at 0.4 mm. And if your print messes up here I'd scrape everything off so the filament and the glue off (I'd keep the bed hot and the tip hot just so I don't have to wait 10 min. for it to heat up again) then apply more glue and reprint.

The issue with my current setup (magnetic build sheet) is that if I level all four corners, the center has so much clearance the first layer doesn't stick.  If I raise the bed so the first layer sticks in the center, it scratches the build surface on at least a couple corners.  That is, the build surface is curved.  I'm not using glass (yet -- ordered a coated one, haven't unboxed it yet), I hope the new glass plate will fix this.

Yeah, that would be a good idea. You could also try to do the auto leveling so that the printer accounts for the dip in the bed (that is if you want to risk the print not coming out perfect) or you could flip the heated bed upside down too

Complicating this is that my printer apparently likes to make a liar of me.  It seems like the bed flattens out when I've kept it hot for a while -- ten or fifteen minutes seems sufficient.  When it's freshly heated ("Print from TF" starting with a cold printer), it's curved, but when it's been hot for a while, it's flat enough to get a  good first layer.

I guess that makes sense because heat makes things expand and when it cools off it contracts again, so when your bed cools off it might bend a bit. You could try to heat it up really hot (90-100c) and leave it like that for a bit, then get two flat things and squish it between the two things so that you could maybe get it flat? (I am not sure if this would work, this is just my best guess)

This is the complete bed assembly -- carriage and heated bed plate plus magnetic sheet layers -- that's curving.  I suspect that the different heating rates and thermal expansion coefficients is at fault, but once it's all equalized it's fine.  Still going to try to the glass build plate.

That would be smart @ZeissIkon I've been printing all week on my glass bed and its worked like a charm knock on wood. I've done like 15+ prints this week and they've all turned out really good.

I've had no issues with the glass bed getting out of flat, but the coating isn't all it's cracked up to be.  Yes, it releases incredibly well when it cools off -- but it doesn't stick as well as all that when hot.  I lost most of a 12+ hour multi-part print over last night because (with PLA) the print warped and pulled up as the print built up, making the corner and edge pieces lose height.  Bed at 60C, maybe too hot -- but it's hard to be sure.


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Is 'natural' colored filament equally brittle compared to white filament?
I've read that white filament is a lot more brittle, because the pigment percentage is close to 50 %, e.g. black filament it's only around 8 %. I was therefore wondering if 'natural' colored filament, which has a somewhat ivory appearance, is also brittle like white filament.
Maybe the color name is a marketing lie or maybe it is really natural colored and there has slim to no pigment in the filament. Making it therefore less brittle. Since the color is closer to white than black I would guess the first one but I would love to be certain.

No
Natural colored filament has no pigments added, the ivory off-white color is the natural color of the mixture in the filament.
Also note, those white filaments can have much less than 50 % volume percentage of pigment, depending on the exact hue of white. The starkest cold whites might make that, warmer white can work with a lesser amount. Pigments are part of the filler materials.  The other fillers make the filament behave in the designed way and can make up a considerable amount of the filament. Usually, less than 40 % are fillers compared to the PLA.


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Printing material for methanol tank
I am trying to print a tank to be used with my RC engine. The material that I have to use needs to have the following properties:

It needs to be possible to seal the final print so that it is not leaking any fluid
It needs to resist methanol, nitromethane (a solvent like Acetone) and lubricating oil at room temperature. It can get discolored or have other changes from the fuel, but it must not be able to compromise the sealing.

I first - foolishly - just printed it with ABS as I do for every fluid container as I can nicely seal it with Acetone. After almost being done with it a friend told me to check the chemical resistance of ABS and as you might guess methanol and nitromethane completely desintegrate it, almost like acetone itself, so that was a waste of time/material.
Next I considered using Nylon. It shows exactly the chemical resistance against all the fuel components I need, however I could not find any (easily available) option to seal the print after printing and after printing a small test container and pouring in some water it leaks after half a minute, so unless I find a way to seal the Nylon containers interior this is also not an option.
I checked various epoxies but the few that I checked all showed poor resistance against methanol/nitromethane.
What I could not test yet but seems like an option is using HDPE. I am using PET bottles to transport the fuel sometimes so it definitely is both resistant and - in theory - watertight, however I am not sure how I can seal an HDPE print, so I am not sure about my first requirement with HDPE. EDIT: I found that Limonene dissolves HDPE and is relatively harmless and easily obtainable. Maybe it can be used to seal the HDPE print surface?
Hence my question: Is there a material that can be printed on a regular desktop printer (heated bed, nozzle up to 255°C) that satisfies both my requirements above or am I "doomed" to buy a moulded plastic fuel tank?

PLA would probably do okay resisting the chemical (it's notably resistant to acetone and similar), but might not have the temperature resistance you need to sit next to an engine.

Most commercial blow-molded fuel tanks for model airplane fuel (methanol or ethanol, nitromethane or nitroethane, and some combination of castor, mineral, or synthetic lubricating oil) are made from HDPE.  This material isn't commonly seen as filament, in my limited experience, but it ought to be possible to arrive at settings that will give a liquid tight tank without further sealing if you can find some.  As you note, limonene might be used to smooth/seal HDPE prints, but likely won't be necessary if your settings are right.
You might want to test PETG filament for its resistance to your fuel mix(es) -- this material is available as filament, prints with settings little different from generic PLA (in my experience, higher nozzle and bed temperature, and a little more bed clearance for the first layer), with good layer adhesion and, with a good print, is liquid-tight as printed.  It's not particularly flexible (as is the case with HDPE), but since you can customize the shape of your fuel tank, it may work for you -- or it may be more flexible in vase mode, as PLA is.
Sealing PETG may be as simple as baking it (similar to "heat treating" PLA to increase print strength, albeit again at a higher temperature) -- this partial remelting will ensure that layers are adhered throughout the print, which (presuming you have avoided under-extruded areas) should be all that's needed to make a printed tank liquid tight.

What temperature can you bake PETG without distorting your print?

Great answer, I have already ordered some HDPE yesterday to tinker around and I did print a water container once with PETG but could not get it liquid tight from the print itself, however with much more experience now I might give it another go as I just recently ordered a new roll of PETG. Ill add another comment later with the results that I saw with both materials.

@PerryWebb Not sure, haven't tried baking either PLA or PETG -- just seen it in videos as a legitimate fix for layer adhesion limitations.  I'd probably start with the same amount hotter than recommended PLA baking temp as you use for printing -- that is, if you print PLA at 200 and PETG at 235, then bake your PETG 35C hotter than you'd back PLA.  Bed it in salt and it'll be a little less prone to warp, too, especially if you can constrain the salt  (tightly fill a can with a screw-on lid, for instance).

After some tinkering with settings (5 wall lines, 5 top/bottom layers, ironing on top, 110% flow, 0.28 Layer height) I got a completely liquid tight print with PETG and it has been holding fuel for more than a day without any leaking or absorption, so the perfect solution.

As a supplement to the answer (doesn't fit well in the comments).  This site https://www.filamentive.com/chemical-resistance-of-3d-printing-filament/ lists PETG has have a very high restance to alcohol, a high resitance to fuel

Is PETG UV Resistant?

In the long run, it is now a well-known fact that it will almost always come out on top when it comes to objects and builds that have to be resistant to ultraviolet (UV) radiation. I.e., UV resistant. This is why it is ideal for objects that have to be kept under the harsh mid-summer sun. This is because UV radiation has minimal effect on it as compared to PLA and ABS.
--
From https://makershop.co/petg-uv-resistance/


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How much time should take for UV lamp to cure resin?
I've bought recently this UV lamp to cure my SLA prints:
But I seem not to be able to get the job done. I got some leftover supports and wanted to throw them in the trash, so I put the lamp onto them, at less than 10 cm, over a cardboard box with foil paper in the walls, and accidentally forgot about it. After 5 hours I remembered, got back, and the resin was still sticky and not cured. Not to say that I should do this for both sides, so I don't think it's a good solution.
I tried another one, this time with the lamp in my hands, and put the lamp over the piece less than 3 cm away. I spent 3 rounds of 5 minutes (that's 15 min) with the lamp pointing directly at it (less than 3 cm away) and it was still not cured, either.
So I'm asking: am I doing something wrong? May my UV lamp be defective? Or is it normal to take so much time? Can you recommend any UV lamp that gets the job done and doesn't take forever?
I already have an Elegoo Mercury curing machine, but it hasn't enough room for big prints, that's why I want to get a lamp that I can use and adjust for bigger prints.

If the SLA Resin is not curing under the lamp after several hours, it is likely the lamp is not emitting the correct wavelength of UV light to properly cure your resin. Typical SLA resins cure at between 350-410 nm light. The listing you post does list the lamp as emitting 405 nm light, which would be in range. However, because of the failures you are encountering, it is likely that the lamp is not emitting any UV light at all and is possibly fake.
SLA parts can typically be left out in direct sunlight for a while to cure, as an alternative without requiring a curing machine or lamp. Finding a lamp on Amazon (or similar retailer) that has a lot of positive reviews (such as this listing) will yield better results as unfortunately UV emitting products are often targets for fakes, as it is impossible to discern if something is producing UV light or not by the naked eye.
It is also feasible to make your own curing lamp (or box) with genuine UV emitting LED's purchased from reputable parts retailers such as DigiKey and Mouser,  but please take safety precautions when working with UV emitters, as the eye cannot regulate the intake of UV light and can cause permanent eye damage!
It may be possible to test if your lamp is producing an appreciable amount of UV light with any bright white object, such as a piece of printer paper, and seeing if it fluoresces. Though this test may not be very accurate.

He could buy some uranium marbles to check UV lamps. Uranium glass often glows green under UV light, it's very nice.

How incredibly unusual. The links are to the Spanish versions of Amazon, DigiKey and Mouser. Usually, the world is so US centered...

I noticed that OP posted an Amazon ES link, so to be consistent for them I included spanish links instead.


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How to create a 3D model as mold for a 4-legged animal with parallel legs
I am new to 3D printing, and new to mold design.
I played around with a model from Windows Paint 3D library:

And I realized that it would not be easy to 3D print a mold out of this.
First of all I focused on the legs, and the fact that I cannot get the 4 legs by just splitting the negative shape into two mold parts.
Then I realized that maybe a zigzag cut could help, but it only work for legs when they are not parallel to each other, unlike the back legs.
And in fact, there is the same problem for the ears.
I'd like to point out that I want to mold paper pulp, so I cannot really do injection molding, which means I really need access to the entire figure from both parts of the mold.
It really seems like it is an impossible problem.
Are there tricks?

Hi and welcome to 3DPrinting.SE! As the mold is projected to be created from paper pulp, what is the connection to 3D printing?

@0scar As I read it, the (preferably 3D printed) mold will be used to form paper pulp.  Biodegradable scatter items, perhaps?

In traditional mold making, this would require a "sectional" mold -- one that breaks into mutiple pieces to free the legs, rather than just two halves.  Sometimes you can use a non-planar mold break line to avoid this issue; look at the molds made for casting miniatures that aren't neatly arranged to see examples, but as you note, with one rear leg alongside the other, the narrow space between isn't accessible with a rigid mold and a molded figure that can't be flexed.
One way around this would be to print the figure and make a flexible mold from it -- the mold wouldn't be printed, but would be molded from a positive figure.  That would let you use a flexible mold material to run a join between the rear legs and still separate the mold, with a little care.  You may also want to make the mold in layers, as would be done for denture making -- using a soft, highly flexible material such as the alginate used in denture making for direct contact with the original figure, and then reinforcing the very soft contact layer with a sturdier backup layer to provide support.

There are brush-on silicone compounds that would fit your description and your methodology is sound.


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Receive M114 command while printing using Printrun
I'm working on a project for which I use the Printrun package to serial communicate my G-code to my 3D printer (Creality Ender 3, Marlin firmware). The idea is that I have an external button connected to an Arduino such that whenever I press this button, the M114 command should be sent and I want to receive the nozzle Z-position.
At the moment the code looks like this:
from printrun.printcore import printcore
from printrun import gcoder

# some code for button
import serial
import time

arduino = serial.Serial(port = 'COM5', baudrate = 9600, timeout = 0.1)
def Button():
    data = arduino.readline()
    time.sleep(0.05)
    return data

printer = printcore('COM4',115200)

gcode=[i.strip() for i in open('MyCode.gcode')]
gcode = gcoder.LightGCode(gcode)
printer.startprint(gcode)

button = Button()
if button == b'1':
    printer.pause()
    print(printer.send_now("M114"))
    printer.resume()

The code is running but I don't get any information about the outcome of the M114 command when I press the button.
Questions:

Is there something in my code that I'm missing? How can I receive the answer from the M114 command using Printrun?
Do you know any other package that allows me to receive the answer from the 3D printer?


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Creality CP-01 3-in-1 printer firmware reset
I bought a Creality CP-01 3-in-1 printer, all working well, until I had an email saying there's an update for your 3D printer.
I downloaded and installed the firmware... and that's when things went bad, the printer head thinks that the front left of the plate is the center so it can't print anything.
I've tried Creality and they say that the update was not for my printer (why then did I get the email ?) only the original firmware is for my printer and you can get it from their website.
I must admit that I'm a bit stupid (no sorry a lot stupid) when it comes to 3D printers, and that is the problem, the firmware update was a file you installed on the printer and job done even though it's wrong.
I've downloaded the files needed but they are not in the right format and everything I try doesn't work.


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Problem with jitters with Ender 3
Recently I realized that I have been getting jitter-like rough surfaces on round parts of my models from my Ender 3. The jitters happen on the sides of the model, so the jitters would be happening in the X and Y. The weird thing is that some parts are smooth and others have jitters. Has anyone else encountered this problem? How do I solve it?
Here is a photo of my hovercraft where it happened the most. (This is all one piece)  As you can see, the section next to the jitters is completely clean. I'm not really sure about what is going on here.

I can't answer it directly but let's do some debugging. Are you sure your gcode and STL files are good (default speeds etc...)? Can you check the tightness of timing belts in the axes? Did you try with different infill settings, are the results are same?

I just tightened the timing belts, but I still get the same result. The bumps still happen regardless of the infill. I'm not really sure if it is my slicer, or if it may be something with the steppers.


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How to fix zits and blobs caused by Cura?
I am using a Creality CR-10S Pro, and lately, I've been having problems with zits and blobs on my surface whenever I do an aesthetic print that has more curves and turns than a functional print would have. I think it started when I started using OctoPrint. I'm pretty sure the slicer is causing it, but I don't know exactly what setting. This are the results I'm getting with PLA at 60 mm/s and 10 % infill:

After this, I just changed the infill to 0 % and it fixed it, but only in the first few layers. I thought I had solved the problem, but after a particular layer, it started again (less than before, but still). These are the results:

This only makes it even more mind-boggling to me. What setting is causing this? I tried changing the maximum resolution and maximum deviation but returned to the first results.

Looks overextruded. Does it appear in vase mode as well?

@towe That was the first thing that came to me -- one or both of overextrusion or overheating the nozzle.

Like I said, the problem started with octoprint. It's not the profile. I just printed the same gcode via sdcard instead of octoprint and it came out perfectly. cura is therefore ruled out too. it's a processor/communication issue.

If you installed on a lower end Raspberry Pi, you could run into problems the the Pi cannot keep up with the printer, what Raspberry Pi did you use?


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Creality 10S 3D fan speed settings and bed temperature
What fan speed should I use with PLA? Do I need to manually set the fan speed in ‘Control’?
Also, on the filament cartridge Bed Temp is listed: "No heat/60-80 °C". Does this mean heating the bed is optional?

What slicer are you using?  Cura 4.9 that I use at home handles fans automatically, do you have reason to believe the defaults are wrong?  What brand/color/type PLA do you have?

Bed heating is not required when printing in PLA. But if it is an option and you would like to heat the bed, I would not go above 70/80 °C for PLA.
As far as fan speed, I would go 90-100 % especially if the bed is heated.

What fan speed should I use with PLA

The answer is that it depends on the hotend temperature the area of the printed layer and the effectivity of the fan. It is best to print some test prints to find the optimum for your printer. E.g. prints with overhangs/slanted object are good tests for this. Normally a Benchy is not a calibration object, but the bow of the Benchy is an example; incorrect temperature (too hot) and too few cooling will result in the bow sagging out.

Do I need to manually set the fan speed in ‘Control’?

No, the slicer can schedule the cooling speed percentage for you.

Does this mean heating the bed is optional?

Yes, PLA doesn't shrink much, so it doesn't necessarily need to be heated up to the glass transition temperature (temperature at which the filament becomes soft) of the plastic. It does require to take extra measures to get it to stick to the bed surface. You also don't want the bed temperature to be too high, this will manifest in poor first few layers quality, similar to elephant feet phenomenon.


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Is it possible to run 2 Ender 3's off one power supply?
I have 2 Ender 3's and I am limited to wall sockets to power both the printers at the same time. So I was wondering if it was possible to wire both the printers to a single PSU? As the printer uses a single xt60 connecter for power to the mainboard, so there is a spare screw terminal on the PUS where the xt60 for the other printer could be screwed in. I am just afraid if I run both printers off one PSU, I might see some magic smoke or else the psu may not be able to provide enough power for them both and may cause print/power failure.

BTW, welcome to 3D Printing Stack Exchange.  You should probably take the [tour] and look at the [FAQ], though you seem to have done pretty well for a first question.

The heated bed alone draws 220 W of 24 V power, so I'm going to say no, you shouldn't attempt to run two Ender 3 machines from a single power supply.
Instead, because the whole machine only draws about 3.5 A at 115 V (or half that at 230 V), you should consider installing a power strip or (better) a small UPS to both power both machines from your existing outlet(s) and also protect the machines from power surges and short power interruptions.  You won't overload your outlets, and you won't risk burning out a power supply by drawing twice the power it's built to provide.

If you intended to run one or both without a heated bed though it might work fine.


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3D print is not smooth, even with ironing turned on
I am very new to 3D printing and I cannot figure out what is the problem is.  I have checked all of the belts and (to the best of my knowledge) they are tensioned properly.  I also did the bed leveling, however it is manual and I did this by putting a paper between the nozzle and the print bed.
I think that my extruder is calibrated, in the sense that when a command is sent to extrude 50 mm of filament, it does.  I am unsure what else to check.
The attached image had 15 % infill in the cubic pattern and had ironing on for all layers, was sliced with Cura and printed on a Creality Ender 3 V2. Sorry about the huge size of the image.
The part that looks zebra-like should be smooth.

I haven't tried ironing it but I don't think it will always be perfectly smooth. By the way I suggest you look your settings and re-slicing. Or try printing a nicely sliced ironing enabled model. You can print a 10x10 mm calibration cubes to try it out.

Z heights are the problem. I had that problem 5 years ago,

@FernandoBaltazar How do I fix this?


text:
Estimating filament consumption in length per time
I printed a lot of models in last month. I spent 2 kg filament in total. I want to know how many hours have been passed while printing. As far as I read, 1 kg PLA (1.75 mm) is about 110 meters long. My default print speed is 70 mm/s. The nozzle diameter is 0.4 mm. The nozzle multiplier in the simplify3d is 0.9 .
In a very basic math,
220÷(0.7×0.04÷0.0175×0.9)=~ 153 hours.
Is this correct?

Your formula doesn't seem to take into account two important factors: layer height and average speed.
Do the math differently:
voumetric flow rate [mm^3/s] = layer height [mm] * line width [mm] * speed [mm/s]
For example, 0.2 * 0.45 * 70 = 6.3 mm^3/s
which is realistic, the extruder on the Ender 3 cannot go much faster than that reliably.
PLA weighs 1.24 g/cm^3 = 0.00124 g/mm^3
To extrude 1 kg you need 1000/(0.00124 * 6.3) = 35 hours (70 for 2 kg).
However the printer does not reach 70 mm except on straight long moves, the average speed may be lower or much lower depending on what you print.
If you print technical parts with straight edges, maybe you can multiply by 1.5 (50 hours/kg), but if you print models and small statues or similar you may need to double it (70 hours/kg).
I use Klipper as firmware and I have a macro which keeps track of printing time and filament length used.

Yeah Klipper is very good but I didn't try yet. 1 Kg vs 70-90 hour made sense to me just as in my math. My models did not have very fine details, but they contained a lot of "support". I'm using ender 3 pro with 70 mm/s feed rate (and 100 mm/s xy speed). Layers are always set to 0.28. Extrusion multipler is 0.48 . With your math do it makes 85 hour?

@user30878 I don't use the extrusion multiplier, since that's a parameter used to calibrate the extruder. I use the final mass and volume of the print and the speed. What do you mean 70 mm/s feed rate and 100 mm/s xy? you canot feed 70 mm/s of filament.

in simplify3d, https://docs.aon3d.com/simplify3d/speeds_tab/ , I mean xy as the "xy axis movement speed" and "default printing speed" as the feed rate.

Your math looks correct, and is also a good approximation for what I've seen in the first few weeks with my own Ender 3.
Another way to calculate (to check yourself) is to calculate the volume extruded (nozzle area times extrusion percentage times print speed -- be sure you convert everything to the same units!) in a given second, multiply by the density of your filament (common PLA runs about 1.2 g/cm^3), and get a rough figure for how long it takes to print a kilogram of filament.  Your actual print time will always be higher than this approximation, because there are moves during which the extruder isn't running, infill is often set to lower extrusion level, and of course there's setup and cleanup time to account for.

Yeah I know there will be extra time but at least this math shows the minimum passed time. Thanks for helping. I only needed the time the printer worked because I will calculate how much electricity I used.

Electricity calculations are tricky.  Both the bed heater and the nozzle cartridge operate intermittently, with higher duty cycle at higher temperatures, lower when the room is warmer or if you have an enclosure -- and they're probably 90% of the power consumption of a printer like my Ender 3.  If that's your main question, however, you should ask that as a question.  There are ways to actually measure and record the consumption of a device over periods of time, too.

Yeah but I measured power consumption in various conditions before, I can make average estimations with those values.


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CR-10 Max slight shock when touching heat bed or frams
I just got my new CR-10 Max and got it assembled. I turned it on, was auto-leveling it, and I received a slight shock from the leveling bed and the frame. Is this a grounding issue? I haven't even printed anything yet and this happens. Anyone have any tips or heard this happening before? I've sent 3 emails to Creality already and gotten no response.

It's probably a harmless thing related to the noise filtering in the power supply. You can fix the issue by grounding the printer. It's been discussed before on this site.

If the above link doesn't help, are you sure its not your bodies ESD to ground.


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What ambient humidity should one target for filament storage?
I live in an arid environment and have never worried about leaving filament out for an extended period of time. To reduce how frequently we receive static shocks I installed a whole house humidifier with a target humidity of 35 %. Is this enough humidity to warrant storing filament in a dry box? At what point does ambient humidity become a concern?

Alternative to dry box: storing it outdoors. ;-)

I've never read about which humidity value, the humidity becomes a problem, but, the higher the sooner water will creep in. Personally, I bought vacuum bags in which I store open spools of filament to shield them from the humidity in house.

The closer to zero humidity the better.  Maybe a garage or some place protected from rare precipitation outside would be better.  If one room is considerably less humid than the others, you could use it.  Keep the bags and dry packs the filament comes in and put them back in when not in use.

I know this is true for most plastics, but some like PVA I think need some humidity?


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What would cause magic smoke with a BLTouch installed?
I decided to purchase a BLTouch for my Ender 3 V2. I did all the physical installation of the BLTouch at the same time as adding LED lighting. I plugged in the power to test the lighting (BLTouch was not plugged in yet) and everything came on fine and the lights worked as expected. I plugged in the BLTouch, hot-glued it in place, and finished zip-tying and screwing in everything else back in place.
I connected power once again and powered on my printer. The fans came on, the new lights powered on, but the display didn't come on. I turned it off and back on, still no display. Then I smelled the distinct odor. I quickly powered off the printer and opened it up to look at the mainboard. I couldn't see any major scorch marks at first, so I decided to power it up again. That's when I saw the small spark and magic smoke at F2 in the picture below.
I feared the worst that I had fried my mainboard, but thought maybe it was the BLTouch. So, I unplugged the BLTouch and powered the printer on and miracle of miracles it powered on. All the fans, lights and display were on.
So something with the BLTouch is causing the short but I don't know what it is. YouTube videos that I watched for installation showed a different cable than the one that came with the BLTouch that I purchased. My BLTouch came with a 1 meter extension that is actually 2 sets of cables. One set is a pair of black and white wires that I deduced were for power. The other cable is a set of three wires colored orange, red, and brown. I zip-tied the two connectors together to make sure they stay together. On the BLTouch end, the orange and black wires are next to each other. The connector in the bottom picture is in the same orientation that I plugged it in.
Printer: Ender 3 V2
Mainboard: 4.2.2
BLTouch: Smart 3.1 from Amazon
Firmware: Jyers' Ender 3 V2 Extensible UI

Given F2's proximity to the linear 3.3V regulator and some inductor and large diode possibly belonging to a switching regulator, it is likely that some short circuit caused the fuse on a power rail to blow.
According to wiring instructions and your picture (if you're holding the connector as it was plugged in, you had it reversed:

Black to the G pins

NOTE: Sometimes blue or brown are used for ground wires

Red to the V pin
Yellow/Orange to the IN pin
White to the OUT pin

If that is the case and the protection was well designed, swapping the cable and replacing the blown fuse should repair the fault unless it also damaged to probe.
As for identifying the fuse value for F2 (T20), different manufacturers, due to the size limitations of SMD components, unfortunately use different markings, but the T would indicate either 0.5 or 5.0A.
It might be best to ask support about the value for the fuse as the manufacturer would surely know.

So according to your answer and referencing my second picture, I really just need to flip the connector. Is this correct?

Just saw where you mentioned that I reversed the connection. That fixed the problem. Thank you.

It worked just like that without replacing the fuse? That is surprising.

Yes. When I first saw that the printer was shorting out, I disconnected the BLTouch and tried powering it on and it did. So the fuse was still good and nothing else seemed fried. Thank goodness!

You might at some point want to replace it anyway because it looks damaged and might not function according to the datasheet anymore.

I'm not confident in my soldering skills for SMDs. Worse comes to worst, I can get a new mainboard off of Amazon.


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Ender 5+ stops while bed leveling
My Ender-5 Plus has started failing.
The simplest path to failure is:

Power On
Settings ▶ Leveling (wait till complete)
Tap measuring

The first zone will measure properly, then when starting to measure the 2nd or 3rd zone while the bed is raising the BLTouch, with probe extended, probe will start flashing red before touching the bed, the bed will descend, then my printer remains in that state (auto-leveling reported at zone 1 or 2, head at position 2 or 3, BLTouch flashing red, probe extended, and bed not moving about 2 cm below probe)
I've also had it fail when attempting repeating levelings, and after starting a print immediately after leveling.  (The printer will level, then the head won't move or extrude while the printer starts to repeat progress on the print).
I've tried printing from OctoPrint (which had worked and now fails) then disconnected that completely and powered off then on to try from an SD card, w/ no success.  I was able to connect the OctoPrint terminal and do some simple gcodes to see if those worked (G0 Z100, G0 X100) and those worked.
I'm not sure what else to try.

This sounds like a broken cable or a problem with the connectors. Please check the cables.

After disconnecting and reconnecting every cable, and doing a wiggle check on each, it still didn't work.
So, I went ahead and replaced the BLTouch sensor with an upgrade from Amazon (Creality BL Touch V3.1 Upgraded Auto Bed Leveling Sensor Kit), and everything started working again.  Huzzah!


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Ender 5 Plus manual screen temperature adjustment
I want to get my Ender 5 plus to print at 300 °C. As such, I've edited the firmware and increased the HEATER_0_MAXTEMP to 315 °C.
In my slicer, I can slice and print at 300 °C, however, I cannot manually adjust the temperature on the LCD screen past the stock setting of 260 °C.
Any help in getting the manual adjustment fixed would be greatly appreciated.

There are two important considerations before approaching the firmware issue: first, do you have an all-metal, direct-drive extruder?  If you don't, your Bowden tube will melt where it enters the hot end and lead to clogs before you ever reach 300 °C (the same may be true of other plastic parts, if present).  Second: is your heater cartridge rated for high enough power to actually heat the hot end that hot?  There are things like silicone socks that can help here, by keeping the heat break and print cooling fan airflow off the actual hot end -- but this may not even be possible with the stock cartridge for an Ender 5 Plus.
Assuming you've already dealt with those potential issues (and given you can print at this temperature via slicer settings, it seems you have), it seems likely that the Marlin firmware has hard coded limits in the adjustment modules or the LCD input module that prevent manually setting the temperature to a range that is none the less within the reach of the actual control PID.  The only solution for this is likely to be analyzing the source code for the input and manual control modules to find and increase that limit (it may exist in more than one location, and they may not all have a value of 260 °C).
Obviously, you'll want to store an unmodified (or at least a known-working) copy of the firmware before you delve into what might be poorly documented or undocumented parts of the code, but the beauty of open source is that at least this is possible.

From what I read on the internet, the TFT screens operate their own firmware, so it could well be found in the display firmware, not the printer firmware. I haven't had the opportunity to fiddle with TFT displays yet, time to order one.

This printer uses a TFT touch screen to interface with the printer firmware (see e.g. this question). The reason that the updated temperature is not seen by the precompiled firmware of the display. If you look at this specific (custom, not standard) Marlin fork you see that the printer firmware and the display firmware are interlinked, this is probably not the case with the default Creality display firmware, it may have hard limits encoded for the temperature.
Looking into the fork mentioned in this answer, you see that the constant HEATER_0_MAXTEMP is used in the display source files, so, running this firmware might lift the constrains encountered with custom Marlin and default Creality display software to modify the hotend temperature to the new set maximum.

Please note, running custom firmware on controller board and display should be done at your own risk.


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My Anet E12 USB keep disconect but still able to print from SD
The problem with my Anet E12 should be on USB connection itself.

If powered down, the board still gets power from USB
If board is resett, USB will still connect
Still works on SD; seem like most part not damage.
What cause the problem? Where to check first? How to fix it?

Note: This printer worked with no problem before.

Sounds like a power saver issue.  Make sure things like your USB ports, hard drive, or anything you need the printer program to access doesn't turn off in power save.

Ok I found the problem. these shameful for me but I decide to share it anyway.
I live in apartment that didn't have earth ground in receptacle. Small electrical shock reallly bother me. althought it also destroy some sensitive component mosfet. (current flow through capacitor in switch mode power supply) Then one day I decide to get rid of these. I hammer ground rod and wire it to some receptacle. these when the whole problem start.
The print shockme many time so I decide to give it a ground but I have no problem with PC so.. I don't give ground to PC.
When these thing connected seem like there are some ground potential diffence. that current flow via ground (shield of USB cable) make PC uncomfartable and disconnect usb device.
luckily pc not broken. I give ground to both device and evrything work fine in harmony again.


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Weird pattern on vertical surfaces on all prints
I recently received my Creality CR-6 SE printer and upgraded the controller board to a Bigtreetech SKR CR6 V1.0 and installed the latest community firmware.
As you can see on the attached image, the corners have this weird elephant foot thing going on the vertical surfaces.

Then there is that zig-zag pattern across the flat surfaces on the sides, makes me think the cubic infill pattern is shining through the sides. I am using Cura 4.8.0 with a modified start G-code to put a purge line on the side before print to prevent drooping in the middle of the bed while probing for the Z0.
What causes these issues? I have not tweaked anything regarding the extruder aside from adjusting the screws that clamp the filament as the stock setting broke the filament when retracting because it clamped on too hard.

I have not changed the E-Steps, on the stock firmware this wasn't even possible.

I use Raise3d Premium PLA filament, I have tried a few and I'm most comfortable with this filament.
If this is over extrusion, I can totally work with that. I have done E-step calibration before on my Ender3. I will test for that after the current print is done.

Corners are extremely rounded, probably due to overextruding. We need more information to help you out, speeds temperatures, material, cooling flow, linear advance, some slicer settings like amount of walls, etc . Furthermore, it is better to print some 20 mm calibration XYZ cubes rather than an object unknown to others. I hope you can provide the info in an [edit]! Thanks. Do note that a complete new board requires everything to be checked and properly adjusted in firmware.

Right, I did print a calibration cube as the first print ever made on this printer, well I printed two, first one very clearly under extruded as there were missing lines, second one looked better but had the same pattern on the sides and weird rounded corners. I'll edit the post with details you asked for.

Overextruding corners aren't fixed with E step calibration. It can be a result of too fast printing, or incorrect linear advance, etc.

never changed linear advance, what happens when you put in a positive number there?

You only insert a number based on what the LA test print tells you, never adjust any number for the sake of changing. You need to calibrate, and possibly adjust flow afterwards in the slicer. Search the site, there is lots to find on bulging corners.

Seeing the infill from the outside is usually caused by having a thin wall or an incorrect wall thickness compared to your nozzle. Wall thickness should be a multiple of your nozzle diameter; so a .4 mm nozzle should have 0.4, 0.8, 1.2 mm thicknesses.
The following list of solutions is from All3DP's article "Troubleshooting Common 3D Printing Problems" under the heading Infill is Visible from the Outside:

CHECK THE SHELL THICKNESS
Make sure that the value you have selected for the shell thickness is a multiple of the nozzle size.

INCREASE THE SHELL THICKNESS
The easiest solution is to increase the shell thickness. By doubling the size it should cover any overlap caused by the infill.

USE INFILL AFTER PERIMETERS
Most slicing software will enable you to activate Infill prints after perimeters.

In Cura open up the ‘Expert Settings’ and under the Infill section tick the box next to ‘Infill prints after perimeters’
In Simply3D Click ‘Edit Process Settings’ then select ‘Layer’ and under ‘Layer Settings’ select ‘Outside-in’ next to the ‘Outline Direction’.

CHECK PRINT PLATFORM
Check around the model and if you see that the effect is more prevalent on one side than the other, the effect could be due to calibration. If so run through the usual calibration process.

PRINT SHELLS TO YOUR ADVANTAGE
Depending on the type of model that you’re printing you can use the internal and shell printing order to your advantage. When you want a high-quality print with a good surface finish where the actual strength of the model isn’t important, select print from the Outside-in. If however the strength of the print is paramount then select Print from in Inside-Out and double the wall thickness.
The reason for the difference in strength is that when you print from the Outside-in you eliminate the small amount of overlap that causes the ghosting issue, but this also means that the actual structure won’t create the same strength of bond between the internal and external structure due to the lack of overlap.

Thank you for the tips, my extruder is having some issues so I'm going to replace it with a dual drive metal extruder. this probably won't fix this issue but I've been having issues with missed steps and they've become more frequent lately, like slipping when it tries to push filament, I can't easily clean the drive wheel because of the closed extruder. I will test tweaking the shell thickness, once I have the new extruder in place and properly calibrated.


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Ender 3 V2 really bad layer shifting
I currently have the V4.2.2 motherboard and it is producing some very poor prints on the X- and Y-axis. I have tried many quick fixes to no avail. Every print out of the box more than a few cm tall has these major defects. Belts are sufficiently tight, the bed is level, the printer is on a flat sturdy table, and I still have this issue. Thanks for your help

I'm not convinced that this defect falls in the traditional category called "layer shifting". Have you checked the bed and the portal assembly for play?

Layer shifting can be caused by a number of different things. The following list of solutions is from All3DP's article "Troubleshooting Common 3D Printing Problems" under the heading Print Offset in Some Places:

CHECK THE PRINTER HAS A STABLE BASE
Place the printer on a stable base and in a location where it will avoid being knocked, poked and generally fiddled with. Even a small nudge of the printer can shift the print base and cause issues.

CHECK THE PRINT BED IS SECURE
Many 3D printers use some form of detachable print bed. Although this is handy when it comes to removing prints and avoids damage to the printer, it also means that over time clips and screws can work loose. Make sure that when you reinstall the print platform it’s clipped or bolted tightly in place to avoid any slip or movement.

WATCH FOR WARPED UPPER LAYERS
A print’s upper layers can easily warp if cooled too quickly. As the layers warp they rise and can cause an obstruction to the nozzle as it moves. In most cases the print will release from the platform, but if it doesn’t the powerful stepper motors can push the print and platform around.  If your prints are suffering from warping in the upper layers try reducing the speed of the fans slightly.

REDUCE PRINT SPEED
It is possible to speed up the print times for your machine by increasing temperature and flow. However whilst this may result in the filament flowing in the correct quality the rest of the machine may struggle to keep up. If you hear a clicking during printing this could be a sign that the printer is going to fast. If you do hear a click the first port of call is to check that the filament isn’t slipping, before you take a look at the actual printer speed. You can adjust your printer’s speed easily enough in any good slicing software.

CHECK THE BELTS
If layers are still shifting then it’s time to check the belts. A quick check is to just go around all belts and pinch the two together. The tension in each belt should be the same, if not then you’ll need to adjust the belt position to even out the belt tension. Over time the rubber belts will stretch (You can often tell if they do as they’ll start to slip on the drive pulleys), if there is quite a bit of play in the belts then it’s time to replace them with new ones. Over tight belts can also be an issue but this is usually only a problem if you’ve built the machine yourself. Some printers such as the Prusa i3 have belt tensioning screws that enable you to easily adjust the belt tensions.

CHECK THE DRIVE COUPLERS
These are usually connected directly to a stepper motor, and one of the main rods that drives the print head. If you carefully rotate the coupler you’ll see a small grub screw. Hold onto the rod and taking hold of the attached belt and then tug the belt and try to force the pulley to turn. You should find that there is no slip between the coupler and stepper or rod. If there is, tighten the grub screw and try again.

CLEAN AND OIL THE RODS
Over time debris can build up on the rods which means that at some points along their length they encounter an increase in friction. This can affect the free movement of the head and cause layer shifting. A quick wipe and re-oil of the rods usually solves the issue.

CHECK FOR DEFORMED RODS
If you see the print head falter at certain points then it could be that one of the rods has become slightly bent. You can usually tell by switching off the machine so there’s no power going through the steppers and then move the print head through the X- and Y- axes. If you feel resistance then you know something is amiss. Start by seeing if the rods are aligned, if they are then remove the rods and roll them on a flat surface. If any are bent then it will be quite obvious.

This has a good order for checking.  Try an additional adhesive layer (glue stick or hair spray) and try lifting z by one step size when moving the extruder and not extruding.


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How do I fix mini-blobs on the edge of a part?
I am using an Ender 3 with a Micro Swiss hotend and a 0.8 mm nozzle, Polylite PETG filament and a masking tape covered glass bed. I have used Cura for slicing with settings:

Layer height: 0.32 mm
Wall line count: 2
Printing temp initial: 255 °C
Printing temp after first layer: 245 °C
Bed temp: 80 °C
1 brim
Print speed: 40 mm/s (10 mm/s for initial layer)
2.3 mm retraction at 20 mm/s
Fan speed: 0 % for first layer, 40 % after

It is also interesting that the problem did not occur on half of the part, but did occur on the other half. Is the problem due to the slight warping up of the part, or due to something else? How can I fix it?

Retraction can help a little but you need a cooling system that helps to reduce heating while the nozzle starts the upper layer. This is a common issue on small parts on the other side where the air flow is almost null. If you rotate the part for printing you can see some differences.

What you are seeing is what is called the 'seam'. Since this part cannot be printed in vase mode (where the extrusion is essentially done as a compressed spiral), there is a point where the printing on a layer ends, and the printer moves to the next layer. This is where the seam is formed. Blobs that form at this change in layers are not uncommon, but the ones in your print seems larger than expected.
You can experiment with larger retractions settings which normal reduce the size, but these seams cannot be avoided completely.
Another change is that most slicers have the option to place the seam at different locations on your part, including placing them at random locations. This removes the pronounced seam, but put little blobs all over your print. Sometimes that is preferred for accuracy instead of the specific seam.

Thank you so much! I will try increasing retraction, and perhaps the coasting setting in cura.

Much better than to use retraction, is to calibrate pressure advance... retraction between layers is not particularly effective

Some slicers also have an option to move the seam inside the part.


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Gantry crashing into bed after print
I've upgraded my Ender 3 Pro to the point where I'm causing myself problems, one of them specifically is this:
My z axis drops down to the bed because of all the stuff hanging off it (added a bltouch probe, cable chain) whenever it is idle, example video of what I am talking about.  When it first started happening I bought an Anti backlash leadscrew nut and installed that and it helped A BIT.   The gantry wouldn't drop as often or as far.
But it still happens.  I've thought about possibly adding a dual z axis motor and leadscrew anyway (with additional anti-backlash nut), and I wonder if that'll help because the gantry would have to overcome the friction on both sides.....   but in the meantime I want to solve a very specific problem it causes:
I just printed a benchy and right after the print was done (when I wasn't paying attention and before I noticed) the nozzle crashed right down into the print.  It must have still been a little hot because it melted right into it.  Not far enough to ruin it but I could see this causing an issue if it was something besides the Benchy.
Is there code I can run at the end of a print to tell the hot end to move out of the way?  So if it does come crashing down its off in the corner or something?   I use Cura and marlin if thats relevant.  I did see this question  but I guess my even dumber question is:  if that code works, how do I add it?  Is that in Cura?

To clarify -- your gantry is heavy enough to back-drive the Z screw when the steppers are disabled?  And the only thing you've added (that weighs anything) is the BL-Touch sensor and its mount?  FWIW, my Ender 3 raises Z about 10 mm and then parks to min-X and max-Y at end of print.  Yours doesn't?

@ZeissIkon  I BELIEVE that is accurately describing whats happening.  I never saw the gantry slide down when idle until I installed the bltouch.  For instance (now) if I turn it on, wait a second or two and then just breathe on the gantry or flick it or something, it'll start sliding down.
As far as where it parks, I never really watched it after a print, but when I came in an noticed the nozzle on the benchy, the print looked done and there were no error messages.  It was just buried a mm into the top of the chimney

You've got a ball screw as your anti-backlash Z drive?  That alone makes it easier to back drive the Z screw.  What you describe sounds more like a last-layer machine reboot (mine has occasionally done this, I think due to power flickers too small to notice otherwise).

@ZeissIkon  one other possible relevant change I made was that I swapped out the board for a BTT E3 RRF and installed their copy of marlin.  I suppose the "parking" at the end could be different now.  Is that somewhere in the firmware?

As far as the ballscrew question:   For the z drive it was just the stock ender 3 pro with the anti-backlash nut from that video I linked.

I think the parking is in firmware, but I can't picture why you'd park above the new part instead of clearing the hot end and gantry and then pushing the part out front.

What you describe sounds more like a last-layer (or near-last-layer) machine restart than a problem with the Z axis back-driving (though it shouldn't back-drive from the weight of the gantry alone; you may need to tighten things like the anti-backlash nut or Z rollers).
My Ender 3 has, a few times, restarted after 3-6 hours of printing -- leaving the nozzle in a lump of plastic that has oozed as it cooled, and the "resume or stop" selection on the LCD.  I haven't seen any indication of overheating, excessive current draw, or other issues with any of my (box stock) components.  I have ordered a small 300W UPS to let my machine ignore the (presumed) tiny power flickers that I believe are resetting my mainboard -- but I won't know for certain if this solves the problem for a few weeks after I get the UPS, because the problem has been sporadic even with overnight and longer print times.
With your upgraded mainboard and using the firmware provided by that supplier, you may no longer have the resume feature that was standard on my Ender 3, nor the end of print park (which, in any case, would not happen in the case of a machine reset).

Who knows if I should have officially "accepted" this answer until I try it all, but very helpful info so I went with it.  I'll check my firmware for both the "parking" and the resume feature (it didn't say anything like that on the screen, it just said 'ready', but again, maybe that was not in the firmware.