text:
File size limit in 3D printing software
Odd question for everyone, hope it has a distinct answer.   I'm often printing bone models derived from CT scans (I work in a hospital) and they often have something on the order of 5 million faces +/-.  Now, I know from experience that I can decimate them down to 10-20 % of the original faces and they still pretty much look the same, so I often do that to help my computer run faster.  I also know that "GrabCad" (the software for my j750) can handle these face counts and the limiting factor is more so the actual physical print resolution.  But it got me curious:
Lets say I was using other software.  Lets say more universally available software such as PrusaSlicer or Cura.  Now obviously if I'm printing on a Prusa I probably don't need to worry about capturing all the detail from 5 million faces because I doubt I can print that intricately, but lets take the actual printing out of it (and I guess even before it gets to the G-code stage).
Can Cura/PrusaSlicer handle that many faces?  Is there a limit?  Do files get "dumbed down" at all when they come in?  What I'm trying to ask exactly is outside of the G-code and actual printing step, can the software side of things handle something with 10 million faces? 20 million? Is there a limit?

I don't see why there would be any hard limit to the number of faces that can be handled, so long as you're willing to wait for your computer to do the work and there is sufficient memory available.

I can't answer with a specific figure, but from experience, I can tell you I've crashed three of the more common slicers doing as you describe. Many faces means the program is working at an unusual level and as you've noted, an excessive detail reference. When a windows program is "not responding," one might wait and hope, but as soon as another operation is requested, "not responding" is again expected.

I have loaded a ridiculous sized STL one. Like, almost a Gigabite. It was processed within some hour and then took ages to slice ("task unresponsive")

@Trish Got ya.  So it sounds like IF there is a limit, its so large that in effect it'll never be an issue

@JosephCrozier the limit is not software but your hardware.

A much bigger issue/concern will be your printer. Just because you have all the faces doesn't mean you'll necessarily be able to print them. I.e. if you have a face that 0.001mm on one edge, but your nozzle is 0.1 mm you're not going to be able to print it (it's more complicated, but I think that shows the idea). You could probably run your stl through some type of low pass filter/patcher and extract the meaningful geometry. Not sure if there's a stock software that does that, but it's doable/plausible.

As a software developer and 3D printing enthusiast I can tell you that indeed, as Trish said, the limit is your memory (RAM) and loading/slicing time depends on the CPU power.
RAM: keep an eye on the memory usage in the task manager/performance/memory tab. When it reaches the top of the graph, the application will suddenly crash and disappear.
CPU: The application (Cura/3D Slicer/Prusaslicer) can become "not responsive". This does not always mean that the process hangs. It just means that the CPU is very busy and the program is not reporting the progress to windows. Most probably the application will recover from this if you just choose to wait.
Files do not get dumbed down when imported, as far as I am aware, in Cura. They are shown exactly like in the STL. Don't know about other software though, but I doubt this happens.
As you noted, this has nothing to do with G-code, which is loaded serially.

As a new Cura UltiMaker user, I found that when I tried to load a very detailed STL file, I received a message that it had too many faces. On checking the Cura site, it said that the limit was 30K faces. That may be a limitation only of the version of Cura that I have (it is for a Fokoos Odin-5 printer).


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What can I do to remove the rounded corners using Junction Deviation?
I recently upgraded my Creality Ender 5 with an SKR Mini E3 V2.0 running Marlin 2.0.7.2.  The printer has also been modified with an all-metal hotend and a direct drive conversion kit that uses the extruder stepper motor.   In test prints of the XYZ calibration cube, I have found that the edges of the cube are rounded over.  After some research, it appears this is due to either the acceleration/jerk settings or the junction deviation settings.
The issue now comes in that no matter what setting I change, the prints do not change.  Currently in the Marlin firmware, I found that the Classic Jerk is disabled in Configuration.h line ~786.  The default JUNCTION_DEVIATION_MM is 0.013. Since Classic Jerk is disabled, Junction Deviation shows up in the menu under Menu --> Configuration --> Advanced Settings. I printed 4 cubes for 4 different Junction Deviation settings:  0.013, 0.075, 0.130, 0.300.  All cubes have the same characteristic over-corrected corner with no visible changes (Picture below)

My questions are:

Why aren't the prints being affected by changing the Junction Deviation setting via the menu?  The Junction Deviation setting is stored in memory using Menu --> Configuration --> Store Settings and I have confirmed the values remain in memory after cycling the printer.
If Classic Jerk is disabled in Marlin firmware, would an M205 X[Jerk] Y[Jerk] Z[Jerk] command before a print enable Classic Jerk for that print?
What happens if an M205 command is sent that sets XYZ as well as J? (e.g. M205 X[Jerk] Y[Jerk] Z[Jerk] J[Dev]).  Would it ignore Classic Jerk values if Classic Jerk is disabled in firmware?

I have read through the following posts already

Setting Junction Deviation in firmware has no effect
https://reprap.org/forum/read.php?1,739819
https://blog.kyneticcnc.com/2018/10/computing-junction-deviation-for-marlin.html
https://www.reddit.com/r/3Dprinting/comments/dx8bd/here_is_why_you_should_disable_junction_deviation/

My next steps:

Re-enable Classic Jerk in Marlin and see if the print behavior changes
Other?

To be sure, you aren't printing these cubes at high speeds? What is the speed?

@0scar: At low speed you should see the issue mostly go away.

I am printing at 70mm/s in X and Y.  Other details that I neglected to mention in the main post but will add:  I have modified my Ender 5 with an all-metal hotend and direct drive using the standard stepper motor.

Apart from the corners, the extrusion process doesn't look that good either. What material are you printing? E.g. PLA doesn't really benefit from an all metal hotend, it is not an upgrade as many believe it is. An all metal hotend is an upgrade if you print 260+ °C materials like some nylons or PP.

Contrary to what's implied by its name, junction deviation does not produce rounded corners. It merely allows violations of the acceleration profile at corners that would be allowed if the corner were rounded by the deviation. So you should not expect changes to it to create or eliminate unwanted "rounded corners".
However I don't think what you're seeing are rounded corners. They're bulging corners, likely produced as a consequence of the toolhead moving slower just before and after the corner in order to honor the acceleration profile. My guess is that your acceleration limits in Marlin 2.0 (500 mm/s² if I recall correctly) are a lot lower than on the original Creality firmware.
You can and probably should increase the acceleration limits. The machine should handle 1000 mm/s² easily and up to 3000 mm/s² or even higher with some ringing; I use lower acceleration for the outer walls and let it run wild for inner walls and infill. But the real solution to your bulging corners problem is to enable and calibrate Linear Advance to get a consistent extrusion rate with varing speed. For my Ender 3, the right constant is around 0.5-0.6 s (yes the units are seconds - it's mm/(mm/s)) for PLA. You can use the calibration pattern generator to run the calibration yourself, but I would expect the same results.
This will significantly impact your print speed, since Marlin applies E-axis speed, acceleration, and jerk limits to the advance offsets. You can get a lot of it back though by increasing those limits though; the defaults are a whole lot lower than what the machine can handle. 200 mm/s speed limit and 10000-15000 mm/s² acceleration limit (vs 25 and 5000 defaults in Marlin, respectively) are within reason.

I commented above, but wanted to add here as well.  I have modified my Ender 5 to include an all-metal hotend as well as a direct drive conversion using the original extruder stepper motor.  Do your recommended acceleration limits still apply for this setup?

I'm not sure, but that would be relevant info to include in the question. As long as the extruder and hotend still weight less than the bed though any acceleration that works for Y should probably work ok for X.

When a junction deviation is set too low it will mess up every other thing you have been trying to do to perfect your extrusion.
It messes up

retraction,
linear advance,
s-curve,
the entire print.

I had been messing around with my jerk and acceleration values, my retraction values, and my linear advance values, and no matter what I did, nothing fixed the actual issues. I even gave up on Bowden and tomorrow a Hemera direct drive will be delivered.
Now I found this setting in my printer menu, changed the value from 0.017 to 0.2  and those bulging corners are now gone (in fact I had to up my linear advance a bit because it was actually rounding off the corners making them too thin).
The stringing is gone now as well (low jerk on retraction and you might as well not retract at all).
Seriously, unless you are using a CNC or CoreXY, I don't see why you would even use junction deviation.
As to why nothing is changing for you, this is because other settings are bad as well. So it's still slowing down too much in the corners while material is still oozing out.

That’s cool to hear that jerk/JD speed can help with the retraction issues. I have been having a hell of a time getting retraction fixed and I think this may be the issue. I’m calibrating now. That said I do use JD because it’s what came with the firmware I got for my BLtouch. I haven’t figured out how compile my own firmware yet, but I really need to, because there’s issues with every version I have found. Just settings that are less than optimal like JD enabled, or soft endstops set to true.

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Shell doesn't cover the entire inner wall at some areas
How do I improve/increase shell coverage so that it covers the entire inner wall?
I've experimented with shell settings, but I can't seem to get it right.
I'm using Creality Slicer 4.2.1 (Cura)
Picture showing the areas in question below:

Green is "top" red is "wall".

You should increase the top layer thickness according to Ultimaker Cura support:

Top/bottom thickness
With the top/bottom thickness you can set the thickness of the solidly printed top and bottom layers of the print. A higher value ensures all gaps on the top and bottom layers are closed completely. However, this can also increase the print time and amount of filament used.
It is advised to always use a multiple of the layer height for the thickness of the top and bottom. This means, for example, that with a layer height of 0.15 mm, it’s better to set the top/bottom thickness to 0.6 mm rather than 0.7 mm.

Thanks. I played around with top layer thickness, but I can't seem to get that single top layer to cover the entire curved shell.

@bigpow What do you mean? A single layer instead of the multiple layers? That is not simple, it is called non-planar slicing, see e.g. this website.

Thanks. I'm new. I don't understand what I don't know. I thought it would require editing the original 3D model to increase the poly # (to smoothen the gradation), but then again, that probably be printable since the printer resolution is fixed. Another rabbit hole.

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


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Dual extruder with gear shifting
I am planning to upgrade my printer with a second extruder. Since my printer is a Tronxy X8 it's frame is not exactly vibration resistant, so I'd like to keep the print head weight down. At the same time I really don't want a Bowden setup.
I came up with the idea of making a dual extruder driven only by a single stepper with a gear shift setup that switches the stepper between the two extruders.
The idea seems simple, but googleing didn't turn up anything else.
Is there anything I am missing that would would make such a setup unfeasible?
Did anyone else build something like that?
A clarification, because it came up in an answer:
What I imagine is this:
One stepper motor is connected to a gear shift system that is either connected to Extruder A or Extruder B, depending on the gear. When shifting it just connects the stepper motor to the other extruder. So it is still similar to a regular direct driven dual extruder system, except that it only uses a single stepper to drive two extruders, each connected to it's own hotend.

That is perfectly viable these days in Marlin firmware, there are options for setting this up using the configuration file, e.g.:
// :[0, 1, 2, 3, 4, 5, 6, 7, 8]
#define EXTRUDERS 1
...
...
...
// A dual extruder that uses a single stepper motor
//#define SWITCHING_EXTRUDER
#if ENABLED(SWITCHING_EXTRUDER)
  #define SWITCHING_EXTRUDER_SERVO_NR 0
  #define SWITCHING_EXTRUDER_SERVO_ANGLES { 0, 90 } // Angles for E0, E1[, E2, E3]
  #if EXTRUDERS > 3
    #define SWITCHING_EXTRUDER_E23_SERVO_NR 1
  #endif
#endif

You'll need a custom firmware.
Yur custom firmware will have to react to the "Change extruder" command differently than a normal firmware: instead of just swapping to a different extruder, you'll need to perform some operations to alter the gearing (possibly a solenoid?), and possibly include some kind of "break" to make sure that the filament is not slipping back without the extruder attached. However, there already is a setup that pretty much does this: the Prusa MMU2 uses something similar. The MMU does use a Bowden setup, but you could use Bowden and direct drive in combination, especially if both motors run in sync.

I think you misunderstood me. I would still have two extruder gears that stay with the filament. I would just have a gear shifting system that would connect the stepper to either of the extruders. That way no filament cutting is involved. All it needs is a servo or something to move the stepper's gear to one or the other extruders. Marlin should be able to handle that.

@Dakkaron Solenoid. You want to trigger a solenoid. But in either case: you need to make your own firmware, and you can look into how the MMU2 gets away with doing a "tool swap" without using more than one extruder motor.

Marlin has built-in support for servos etc. to be triggered kn tool change. I am  programmer, so I am not worried about the software side. It's more the hardware side that I am worried about. The solution sounds simple, but I have never seen it implemented, so I am wondering what I am missing.

@Dakkaron hm... how about start with a sketch? one or two hotends?


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How to move Z up after printing in Cura?
Simple question, I want to move my printer head up when the print finishes instead of to the side.
Where's the option to do this in Cura?

Does it have a Custom G-code section, where you could add the command to the End G-code?

Go towards the right top corner. Click on the printer name. From the drop down, select, "Manage printers". You will get a dialogue box in the middle of your screen. Your current printer's name will be shown in italics. On the right side of the dialogue box, click on, "Machine settings". This will open another dialogue box. In the lower left, you will see a text box with the heading, "End G-Code" scroll down to where you see the line, "G1 X0 Y0". This is the line that moves your print head to the lower left corner. G1 is the command for a linear move. X0 and Y0 are move instructions to move the the 0 coordinate for the two axes. Change this line to G1 Znn where "nn" is the number of the coordinate you wish to move to. Close this dialogue, close the previous dialogue and all newly sliced file will now use this code.
If like to keep track of any changes you make, you can put a semi-colon at the beginning of the line. This turns the line into a comment and will not be actioned. Then press enter and on a new line, put the line, G1 znn.

Thanks, do you know the Gcode for relative move? Like ”move Z 10 from where it is?

That would be G91. You can get all the G-Codes here link.


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How to treat PLA (Polylactic acid) plastic to make it biodegradable?
I am using PLA for 3D printing, and I know it does not degrade well in the wild. I would like to know if there is a chemical process I could use to treat it at home.
Specifically, I am looking for a cleaner alternative than throwing my 3d printing scraps in the garbage, so I wouldn't be generating toxic components when doing this, ideally. I want the plastic to degrade (in a few years, maybe?) when I put it underground while limiting the amount of toxic matter propagating in the soil.
I have read that hydrolyzing PLA could help to achieve this. I also found threads on dissolving it (How to dissolve PLA (polylactic acid)?). But as I am looking for an eco-friendly process, I think I need to stay away from this as the fumes may be very toxic and polluting
Posts like this one Can I really throw failed PLA prints on compost? mention a few requirements for PLA to degrade but don't talk about a way to achieve these conditions.

A good question, and I was going to leave a semi-informative comment, however, I have added the content of the comment as a new answer to the question that you linked to instead. The article doesn't offer any process for accelerated degrading, unfortunately.

Almost anything you can do is going to have more net environmental harm than benefit. You probably should start by just crushing/shredding the material and trying mixing it with an established organic composting system to see what happens. For this to be environmentally friendly you should be using the purest PLA you can get, unpigmented, and not any sort of "PLA+" with ABS or other stuff mixed in.

Great question, have you checked with your local council to see where your green waste goes , weather they use an industrial composter, and if it’s ok to put it in your green waste bin otherwise? Sometimes they have special facilities where you can drop off bio plastics like PLA. Kudos for saving the planet :)

@HotGlue I haven't called them, but I tried bringing PLA scraps to the local ecocenter and they wouldnt let me explain what type of plastic it was, so I assume they threw it away.. :(

You can make it biodegradable but it is very hard you need oxygen a temperature of 140+ degrees and a 2/3 cocktail of organic substrate these are usually absent outside of a industrial composting facility.
I had the same question when I got my printer - it's better to just buy recycled filament or recycle your own but PLA is a byproduct of milk production so its pretty naturally sourced anyway.

Hi and welcome. Don't forget to take the [tour]... :-)

Naturally sourced means nothing. PLA still accumulates plastic waste. I agree, you're probably better off using recycled filament but I have one of those printers that use proprietary spools with chips... Im stuck with this until I get a new one

@JCSB: You can just replace the firmware (and possibly also the board) to fix that, without replacing the whole printer. Price will be something like $0-35 plus time spent installing it.

Can you give more details about the '2/3 cocktail of organic substrate'? And the time it would take under these conditions?


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After installing BLTouch and Marlin, my nozzle is too high when trying to print
So I have an AnyCubic i3 Mega to which I added a BLTouch v3.1 and Marlin (1.1.9 due to older, Atmega 8-bit CPU) using instructions and such from this link.
Finally, I've got everything moving in the right direction, I got the auto-bed leveling (bilinear) going (did a 7x7 grid), saved the mesh, tuned the bed and extruder PIDs. Great! Add the G-code into Cura to load the settings and activate the mesh.
Start the printing, goes to home fine, gets up to temp, and then it moves into position to start the print and it suddenly jumps up in Z-height above the bed several millimeters. I pause the printing via OctoPrint, try and use the control tab to adjust the height, not responding. Canceled the print. Used the M114 command to get the position.
Here it is after I hit cancel.
Recv: X:180.63 Y:171.85 Z:0.00 E:9.71 Count X:14450 Y:13748 Z:2120

Here it is after I use G28 to home
Recv: X:-5.00 Y:0.00 Z:0.00 E:9.71 Count X:-400 Y:0 Z:0

Here is the Start G-code settings from Cura
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
M107 ;start with the fan off
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
M501 ; bltouch mesh load
M420 S1 ; bltouch mesh load
G1 Z15.0 F{speed_travel} ;move the platform down 15 mm
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3 mm of feed stock
G92 E0 ;zero the extruded length again
G1 F{speed_travel}
G0 Y20 F{speed_travel}
M117 Printing...
G5

It's almost like the Mesh Z-offset is wrong. I do have a probe Z-offset of -4.60, set via M851. I set this, and then I did G29 to re-do the ABL.
With me being new to ABL and Marlin, what did I forget? Maybe I did something wrong?

As a comment, homing is defined as G28 or followed by an axis letter as a flag, not a zero/digit/number after the letter. The X, Y, and Z parameters act only as flags. Any coordinates given are ignored. For example, G28 Z10 results in the same behavior as G28 Z. from G-code manual. Don't read parameters from memory (M501) unless you changed parameters you want to revert back, there is no reason to to this every print.

In some ways, this reminds me of the pain I went through recently. I am also fairly new to 3D printing.
After you have completed the bed levelling using G29 you should have a list of mesh coordinates showing in the interface with OctoPrint. (I am using Pronterface, so am not all that familiar with OctoPrint). You need to save the mesh coordinates to the control board. To do this enter M500 and then M503 to check that the data has saved. If you enter G28 (don't use the digit after the axis!) after using G29, but without saving (M500) the coordinates will be discarded.
When you have set your Z-offset, you also need to save that too (M500).
Unless you bed is warped, a 7 x 7 grid (mesh) is overkill. If you are printing on glass or a mirror, a 3 x 3 grid should be enough. I have a 5 x 5 due to may warped bed.

So, dunno what happened exactly, but through some additional rounds of ABL, and saving (M500) with some additional firmware writes, because I had to invert a few axis to get them to run right, it's running great now!


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Ender 3 Pro - Randomly skip lines
I am a newbie to the 3D printing world. Every night spending hours researching and troubleshooting. Recently though I am having a weird problem for which I can not figure out a solution. While printing it randomly skips a line or two (see attached photo). I have an Ender 3 Pro that is about a month old. I have installed a glass bed on it and I am using silk white pla. I am printing with the following settings:

210 °C Nozzle temperature,
Bed at 60 °C,
Fan speed at 70 %,
Print speed at 45 mm/s,
layer height 0.2 mm with stock nozzle,
10 % cubic infill,
and plate adhesion type is skirt.

Any help/advise would be appreciated.

Looks like extrusion issues... PLA? Then 210 °C is rather hot.

Are there any sounds like clicking or buzzing coming from the extruder? Is there a lot of dust building up in the extruder?

Can you post your first layer of G-code? Does the rendering show these gaps?

210 is fine for PLA, and hotter shouldn't cause this sort of issue. I normally print it at 210 and 220 on some filament with layers 0.2 mm or larger.

Have you ever disassembled the bowden tube setup, especially at the hotend? Putting it back together wrong can cause this sort of issue.

I didn't hear any unusual sounds asides from the motors itself. There is a bit of residue from the filament by the extruder. I will clean that up and see if that makes any difference.
The render doesn't show these gaps. This happened only in the first 2 layers, after that it printed the rest fine.
I haven't disassembled the bowden tube or the hot end.
I suspect that it has something to do with the extruder. i just can't figure out what is it. As i am writing this, I just realized that the one thing i haven't checked is the extruder  gear. Thanks everyone for sharing and commenting

Sorry for the late update. I am still struggling with this issue. The extruder gear was loose and was falling down, hence missing lines completely as the filament wasn't being fed. I tightened the screws and it resolved it for the most part. It is not as bad as the picture but it is still happening randomly. I have noticed though a few things. It only does it in the angle shown in the picture. Which makes me wonder if it has anything to do with the Y axis.

another thing that I have noticed is a loud clicking sound. It happens randomly and when it happens the extruder gear moves back. Not sure if this is normal. I have recorded a video of it. Hopefully ill be able to upload it. It is 5 seconds and the click happens at 3rd sec.  I have cleaned the nozzle and ensured that the filament flows properly. If anyone else has experienced this or has any thoughts then I would really appreciate it. Thank you all for taking time to read and comment.


text:
How to block UV light (transparent material)?
I want to build my own curing station for my resin printed parts.
I know there are a lot of prebuilt machines but they do not completely satisfy my needs.
I now want to know which material i can use to cover the chamber, but still be able to see inside.
The material should therefore block UV light but still be transparent.

The material should be transparent to only light above the UV spectrum, but should block UV light (UV-A, UV-B if possible)
The material should be purchasable in sheets to be able to build a cover out of it (e.g. acrylic sheets)
the color is not relevant as long as you can see through it

The questions is now, which material satisfies those points?
You can find reference on existing machines like the Elegoo Mercury Pro or the Formlabs Form Wash. Maybe somebody knows which material has been used by either one of them.

I’m voting to close this question because this appears like a shopping recommendation - which is not allowed on the stack.

This is not a shopping question, rather a technical question which material blocks UV

The elego and formlabs machines you point to are cleaning stations and use 400 nm by the way. As a side note: you can't print a material that is transparent to 400 nm light.

Their product pages state otherwise: the elegoo Mercury uses a combination of 385nm and 405nm. The formlabs one uses 405nm. I just double checked. I know I can’t print that, I was thinking about using acrylic Glas or something similar

Transparent to what light is the least you need to point out

Polycarbonate blocks UV.  Have you investigated material properties?

It should be transparent to above UV spectrum light. I researched a lot of materials, but I am unsure about their UV characteristics. A lot of their data sheets (when you buy them online) state things like UV-resistant. Maybe I should rephrase my question: what materials do Elegoo and Formlabs use on their machines?

It might be a good idea to rephrase, but then again, you would be changing the sense of the question completely. I personally would leave the title as it is, but edit and expand the body of the question: firstly with information both requested and that you have added in the comments (comments tend to get cleared up (i.e. deleted) after a while, so you want any additional info in the actual question text), and;

secondly, with information that you have researched yourself, i.e. links to datasheets and quote the relevant information from those datasheets, so that we don't have to go googling and reading them ourselves. Basically the more information the better, and the more likely that you'll get an answer... Hi and welcome to SE.3DP BTW...! :-)

thanks @Greenonline for the comment and the warm welcome. I have updated my question with all the information i have.

If no one here knows, then you might try emailing the manufacturers' support? I have managed to answer some similar type proprietary questions by just emailing the company. Maybe a friendly enquiry might yield some result, although they may not be willing to divulge their company secrets... If you do get a reply, don't forget to post the answer here :-)

I contacted the manufacturers of curing stations directly and got some interesting feedback. Not all of them were keen on sharing their information, but two responded:

Elegoo is using Polypropylene
Creality is using polycarbonate

I am sure they are using some additional UV blocking on the plastics with a coating, but thats all I could find out.
Thanks to @Greenonline for pointing me in the right direction!


text:
What is the best build surface for PETG?
This question doesn't necessarily have one answer.  I'm looking for a build surface that doesn't tear up when removing the PETG print, but still holds the PETG down and keeps it from warping.  I am printing PETG with the z-height almost too high.  Higher causes the PETG not to stick and warp or even release during printing.  But, I still have trouble with PETG prints tearing my build surface.  I've tried PEI and black build surfaces that don't identify the material.  The build plate on my hot bed is glass.

don’t use the smooth PEI side,petg would destroy it,use the rough side or textured side instead.

@FromENG: If you can select the side of PEI that you use, I assume this means you are getting PEI without adhesive and having to apply adhesive yourself, or are you using another method to hold down the PEI?

i have a prusa mk3s the pei is double-sided (smooth/textured) and the sheet is magnetically attached to the y carriage.You can buy one magnetic rubber(the other side is glued to the y carriage) and then attch the pei to the rubber to make a removable surface.For me the textured pei works like a charm.

Yes,usually they just pop off when i bend the sheet.

Removable steel spring sheet with PEI textured coatings
I have been using textured PEI string sheet for most of my prints, just love it.
Prints attach so good but not hard to remove(with proper nozzole Z-offset).
If the prints are small and seems hard to remove,heating up the bed helps a lot.
Almost never used the smooth side, even with proper z-offset, it still damages the surface quite fast.
Here's the link i bought before:
Removal Spring Steel Sheet Pre-Applied PEI+Magnetic Base
This is my setup on a ender3pro:

@FromENG: Do you remove the spring steel from the holding magnet and flex the steel to help remove the PETG print?

Yes,but most time prints just came off when bed cooled down, no force applied.Sometimes (big prints) i need to bend to release.

The spring steel sheet must have a larger thermal coefficient mismatch with PETG than glass.

8 degrees lower on the top surface when i measure the temp,so i always set bed temp 8 degrees higher than Tg of that particular petg's i'm printing with.


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How to interrupt long command with G-code?
I was able to connect my terminal program (Putty) to my 3D Printer (Creality Ender 3 Pro) and was able to send G-code commands to my printer and it obeys.
Now suppose I sent long command like
G29 ; auto bed leveling

and it is still executing. Printer writes me
echo:busy: processing

How to interrupt it?
I tried to send M0, but it didn't work.

3D Printers are pretty basic when it comes to g-code. There is no cycle start or cycle pause function on them. There is also no g-code command to interrupt the previous command. To get it to a halt you could turn it off. Or if the printer's firmware is configured to do so, you can touch one of the limit switches to get it to stop its movements.

G-Code is processed as a queue. The FIFO behavior would disallow to execute any commands in parallel.
However I am aware of - yet I didn't have opportunity to try - the emergency commands M112 or M108 offered by Marlin. Marlin documentation says that EMERGENCY_PARSER and HOST_KEEPALIVE_FEATURE need to be enabled to handle these. So apparently there is a mechanism which may work in parallel (like the higher priority queue?).
These commands may be designed to break execution of some specific actions, e.g. M108 was described to break wait-for-temperature loop. You may want to give it a try.
M0 also requires EMERGENCY_PARSER setting. And it may be bit different than you expect: it is described as pause after the last movement. By contrast, emergency codes (M112 full stop) are designed to jump the internal command queue even when printing and execute immediately, when emergency parser is enabled (command queue would be lost, printer may shut down or user may be forced to reboot the printer).

Some commands are definetely can run in parallel. For example, I can start to heat extruder and meawhile move axes.

@Dims That's not really running in parallel. You're just issuing a "change temperature setpoint" command and once the setpoint has been updated, the command is considered finished. Thre are also G-code commands for changing various other settings (such as the steps per mm) but these are not "running" in any sense after they've been executed.

Commands like "Pause" get inserted after the completion of the last movement. However, there is the abort print command, that stops the execution of any G-code... but throws all commands out.

klipper not support G80 gcode to stop runing move


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e-steps are wrong only during printing moves
I have two otherwise-identical machines (called "Lefty" and "Righty"), so I have a baseline to compare.  I am running Marlin 2.0.7.2 on both machines.  They are Creality CR-10 printers with BTT SKR e3 Mini v1.2 boards, with Marlin I compiled myself.  Both machines are (as far as I know!) running the same exact firmware binary.
When running the same G-code on both printers, Lefty prints fine.  But, Righty fires the plastic through -- I need to set the flow rate to 50 % (!) to be correct.  I have checked the esteps, both are identical at 415, and this produces 39.5 mm of 40 mm commanded when bumped through 1 mm at a time via the extrusion menu, even on Righty.  The XY movement on both machines is 100 % correct.
Volumetric extrusion is disabled in the firmware on both  machines, and disabled in the slicer.  Both machines are running TMC2209 drivers, set to Spread Spectrum at 650 mA for the extruder.  Both machines are set to 1250 accel. The steppers are rated for 1 A, and they are not skipping steps.
The machines were working side-by-side perfectly until I killed Righty's stepper driver with static, and replaced the board.  No other hardware was modified.
Why do both machines behave the same with identical G-code, until extrusion moves?  Why does Righty try and extrude nearly double what it should be, only during printing, when Lefty works perfectly?

Annoyingly, this went away with a replacement board.  I don't have a better fix.

For both machines did you compare extruder's (E) steps/mm setting in Marlin and possibly stored in EPROM (so check from the LCD in Configuration>Advanced settings) ?
Also stepper motors ... I believe they are exactly of the same type? There are 1.8 degree and 0.9 degree stepper motors on the market - so exactly doubled flow could be related to rotation. Also the stepper driver board may be configured for mcrostepping (e.g. full steps agains half steps), and this may equally influence the behavior. (I do not have CR-10, so I cannot advice in more details.)

The machines have identical hardware -- but more importantly an esteps calibration (measure filament, extrude manually, measure again) is spot-on between both machines.

Thank you. And I believe you have also already excluded microstepping difference, and Marlin configuration is equal for both .I've experienced too weak extruder's stepper setup (voltage tuning), caused skipping steps instead of pushing filament (just one of possible extrusion issues). If your e-steps values are near to nominal characteristics of CR-10 (i.e. afaik close to 100 steps/mm)? If it is two times higher, than maybe Lefty just loses steps? Key question: can you see/test if both extruders rotate with the same speed (e.g. print line) - or one is indeed two times faster (doubles amount)?

I can't tell if it's specifically double, but Lefty isn't skipping steps.  I have seen it skip before and it's a very different behavior with notable sounds.  Righty just kicks the extruder gear into high gear when it starts doing extrusion moves.

The pulse for stepper driver have to come from somewere (also btw.: you did not reveal your steps/mm values). There are parameters in Marlin's Configuration_adv.h (HAS_TRINAMIC_CONFIG section) with settings which can influence microstepping values of your drivers, they communicate with stepper driver through pins - but you mentioned the same Marlin and same gcode files.  Have you replaced the stepper driver board or the mainboard? Mainboard pin failures would be worst case (and less likely). Maybe still the driver - did you try to exchange stepper drivers between machines? or even extruders?

I did mention the e-steps value on both machines (415), and the drivers are soldered on with no way to switch them.  I had replaced the entire mainboard.  It began acting up last night in a different way related to the BLTouch, so I'm just going to replace the whole board and see if that helps.


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How to attach PEI sheet to glass for high temperature printing?
I am using an Intamsys FunMat HT, which has a "ceramic glass" bed.  I'm not sure what "ceramic glass" means, the stuff behaves like borosilicate in the way it either chips or shatters depending on how I abuse it -- so lets just go with "borosilicate bed".  It has a glossy side and a frosted side, and as I have permanently damaged the frosted side, I am trying to save the glossy side with a bed surface.
I am trying to attach a sheet of Ultem PEI (McMaster link), using (3M 468MP) tape for printing Ultem 1010 filament.  The 3M tape is rated to 149 C for "days, weeks" (per the datasheet), and up to 200 C for "minutes, hours".  My print bed runs at 160 C, and I was printing an Ultem part on it.  In under an hour, the adhesive had begun to delaminate under just the curling forces of the PEI sheet itself, save nothing of the part attached to it.  The adhesive itself seemed to be peeling apart.
The bed had been baked in a convection oven at 100C for 12+ hours, and was prepped with soapy water followed by Windex and a dry-scrub with paper towels.  Is there a better transfer adhesive I can use that will offer strong bonding of PEI to a glass substrate, and survive prolonged exposure to 160C temperatures?
note: I am not sure this is a duplicate of this 3dpse post, because I think I cleaned the bed well enough, and in this case may just be exceeding the thermal capacity of the adhesive.

I think most adhesives are a mixture of thermoplastic materials. That means that they became soft above a certain temperature threshold. I think you might have found such threshold. Also I have never seen PEI sheets for such high bed temperatures. Their maximum is usually around 100 °C. You could try using a CA glue which is extremely stable and non-toxic. However since the glue is not elastic I think the PEI sheet will delaminate from the glass anyway due to different thermal expansion of those materials.

Have you tired polyimide (Kapton) build surfaces?  They easily withstand your temperatures, but are easier to damage mechanically than PEI.

@PerryWebb: I have, and they don't have enough adhesion for printing Ultem on.  I need to use PEI (or an equivalent alternative).  The adhesive on most Kapton tapes fails at the temperatures I'm printing at, even if the tape itself is fine.

I haven't used it, and certainly now at 160°C, but 3DLac is an adhesive speced as working from 5°C to 180°C.  However, it seems you still have the issue of being too hot for PEI.

3DLac worked too well, that's why the matte side of my glass bed is unusable now, because it pulled huge chunks of glass off with some ABS.


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Ender 3 Pro thermal runaway
From day one, I had issues with the bed unleveling all the time even if I hadn’t touched it.
After watching more videos I bought springs and I was having fantastic prints every time. There was no need for levelling between prints - it worked perfectly.
The day before yesterday I got an error warning thermal runaway printer halted please reset so I did as the printer said and again tried the print and 20-30 mins in the exact same issue. I watched more YouTube videos and replaced the motherboard with an SKR E3 V2.0 mini with Marlin firmware installed on to it.
After installing I went ahead and tried to test print (file on provided micro SD card) and 30 mins in I got a thermal E1 so I went ahead and watched more YouTube videos which suggested that I connect my printer to my PC via a USB (provided) and download Pronterface. I followed the instruction of typing M303 V5 200 into the command prompt and sent it to the printer which again halted the printer with E1 error code. I went over to the printer and unplugged the USB and waited while the printer was off before plugged the USB back in.
After doing this I got a TMC CONNECTION ERROR message on the printer. I followed some Reddit/Github posts that said:

Send command M122 to the printer, this should work, which it did not.

As it stands at this moment this printer has gone from working perfectly to nothing at all.

Please clarify your question:. "nothing at all" doesn't sound like "thermal runaway."

It will print 1 or 2 layers then thermal runaway message comes up with a loud beeping noise

So you replaced the controller board and experience the same thermal runaway behavior. That implies that the board isn't the cause. You need to check the rest of the hardware. Loose/faulty thermistor or heater cables, fan shifting onto the hotend, etc.

I have corrected this issue by fully replacing the hot end and wiring (thermistor and heating cartridge)

I’m guessing you don’t know then


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Will glue sticks form a barrier on a build surface to prevent PETG from damaging the surface?
Will glue sticks, such as Elmer's All Purpose, Cra-Z-Art washable or Scotch Permanent, form a barrier on a build surface to prevent PETG from damaging the surface?  While forming a barrier that holds the PETG print down, does it allow the PETG to separated after the print finishes, so that the build surface isn't damaged?
I found in the description of a glue stick designated for 3D-printers: "these 3D printer glue sticks can be applied to remove 3D models much easier .. made of quality PVP material ... have nice adhesion to hot plate or hot bed, easy to remove the printing models ..."
I'm now using an Elmer's washable school glue stick (PVP).  It is working consistently at bed temperatures of 30°C and 80°C. It both holds the PETG print and releases the print without destroying the build surface.

I don't know for glue sticks, but for 3DLAC (build adhesion spray) it is certainly true! I had a PEI sheet, where PETG used to almost fuse with, a layer of spray helped a lot to decrease the adhesion!

I don't know about PVP but PVA sticks more at room temperature and gets weaker at higher temperatures, see "Influence of temperature on the strength of bonded joints"

I remember using hairspray with PVA for PETG and it was really difficult to detach large parts.

I'm not having trouble with PVP for PETG at 30° and 80°C.  Of course I was having trouble with PETG not releasing from the build surface without the PVP layer.  That seems to be the advertising point for glue stick selling for 3D printer use.

The PVA chart data is from wood joints in which the glue is applied wet and allowed to dry.  When used on a 3D printer bed, the glue is dry before the print and plastic is bonded to the dry PVA instead of wood.  Both are joints, but heating wood can have a drastic effect.


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Ender CR-10 Max with BLTouch won’t level
I don't even know where to begin with this one. From day one I have had nothing but problems. The only reason I still have it is because the store I bought it from is refusing to accept a return. So the issue is out of the box.
I levelled it [paper test] set the BLTouch to do its job [measuring] upon completion. I used Blender to export the default cube I then used Cura to scale, multiply and position a cube in each corner and the middle and set it to print, at this point I was hopeful that the BLTouch did its job but unfortunately it did not. The first layer didn't stick. I cancelled the print, re-levelled and tried again, this time a Mandalorian helmet, thinking that maybe the issue was that I was printing small with a 0.8 nozzle.
About 1/4" to the print and it failed again. This time a better first layer though but to my surprise, when I removed the failed print and hit auto home, it auto homed at about 18 cm (7 inches) off the bed and would not return.
After about 3 weeks I finally received a G-code to reset Z offset and thought I was some what back in business. I levelled the bed let the BLTouch do its thing and set it to print and again the first layer did not stick. Someone suggested that I check the BLTouch pin which looked like a cork screw. I replaced and repeated the level and BLTouch steps and, again, the same issue.
I also tried pre-heating both nozzle and bed to respectively 210 °C and 80 °C and letting the BLTouch do its job and the same issue occurred.
I have learned that natural oils from our fingers can cause the prints not to stick so I bought 100 % alcohol wipes and cleaned the bed, let it dry and repeated the process to be double sure that it was clean.
I air dusted the control box and extruder to remove any dust that may have occurred. I re-levelled and turned the BLTouch off and levelled again in the hope that it would work like a manual bed levelling and had no luck. At this point I'm figuring out that this BLTouch "Auto Levelling" should be called "Auto Unlevelling".

Hi Welcome to 3DPrinting.SE! With "default cube", you imply a test calibration cube? You don't need Blender to scale a print, Cura can do that very easily. Note that Blender is a powerful tool, but it can also mess up models if you don't know what you are doing. What is meant with 1/4" is that length or time? Note that Auto Bel Leveling is sold to simplify leveling, but it does not, it requires some extra steps to set the correct offset. Since your first layer doesn't stick, the initial nozzle to bed distance (defined by the sensor offset M851 Zx.xx) might be incorrect.

People would love to help you out, but, although the question is lengthy, it doesn't contain much technical data to help. Please add a photo of the first level failing, a few lines from the G-code file (must include at least the first use of G1 Zx.xx). This may attract more people and help you solve the issue!

How can I set the initial bed to nozzle distance to the correct value?


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Z-min always open when using BLtouch and Marlin 2.0
I recently added a Creality BLTouch v3.1 to my Ender 3 which has a MKS Base v 1.6 motherboard and is running Marlin 2.0, but the Z-min never triggers.
I have made sure that the BLTouch unit lights up, uses the provided mount for the Ender 3 to get proper placement and is connected to the Z-min pins. Additionally, I have followed multiple youtube videos for connecting/setting the right parameters for the sensor. However, I haven't found the right combo.
I have tried both BLTouch and Creality BLTouch, different pin number assignments (other than the standard Z-min pin), but the status doesn't change with or without the sensor pushed in. Looking for suggestions on settings to apply, or if anyone has had this issue.
See pictures below:

Connection to motherboard, tried using the other pin on the z min, and switching the black/white wires to see if they we're connecting wrong.
BLTouch depressed which lights up as expected.
BLTouch not illuminated when open.

I updated the firmware and enabled BLTOUCH as well as AUTO_BED_LEVELING_LINEAR. When I powered on the printer, the unit does a self test and returns to the "triggered" position and the light is on, however Marlin still sees it as open. I also have Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN defined so I would expect it to recognize the BLTOUCH status correctly.

What do you mean with "Marlin still sees it as open"? Please update the PasteBin files with the latest configuration edits, the first posted are now out of date.

Only changed Configuration.h so here's the link for that https://pastebin.com/r72JJTya
If I run M119 to check the end stop statuses, Marlin only shows the Z stop as "Open". I can trigger the BLTouch and see that the light is red, but after issuing the M119 command, Marlin tells me Recv: z_min: open. If I pull out the sensor on the BLTouch and the light is off, I get the same message from the M119 command. I also tried this on all 4 server pin sets just in case I hadn't put the correct pin in my config, and each time the BLTouch completed the self test as expected.

Why would you want to run M119 with a BLTouch? That doesn't make sense to me, furthermore it is the first time I ever heard anybody do that. The documentation already expresses that you cannot do that! The BLTOUCH probe only sends a brief pulse, so “TRIGGERED” indicates the probe is in error state. So, your status being open is a good thing!

Ah I had missed that bit. That's good to know that the seeing the open status is good in this case. Through Octoprint I tried to run the bed leveling function which called G28 command, but during the homing process, the Z axis kept trying to decrease and ran into the physical stop on the Z axis. If I take out the physical stop, the hot end continues to press down on the bed, so I end up killing power to the printer. I have set the probe offset to what others have said is right for the Ender3, but the printer tries to home where X=0 and Y=0.

In order to use a BLTouch probe (or clone probe) you need to configure the firmware to know that a servo operated Z endstop is being used.
From the referenced files that are used for building the firmware you are running can be found in the configuration.h that:
/**
 * The BLTouch probe uses a Hall effect sensor and emulates a servo.
 */
//#define BLTOUCH

When using a servo port operated probe (position of the servo corresponds to a certain action) such as the BLTouch, 3DTouch, etc. you need to configure using it as such:
/**
 * The BLTouch probe uses a Hall effect sensor and emulates a servo.
 */
#define BLTOUCH

Furthermore, you need to be sure to connect the cables of the touch probe according to the pin arrangement as defined for you controller board.
E.g. #define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN could be used to re-use the Z-min endstop connector on the board.

Note that when using a touch probe (which is a sophisticated sensor with it's own onboardmicro-processor with dedicated firmware), you cannot use M119, the endstop status from the touch sensor cannot be read from the output of the command. According to "Marlin documentation", The BLTOUCH probe only sends a brief pulse, so “TRIGGERED” indicates the probe is in error state..


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Proper belt tension for Ender 3 v2
The Y-axis belt just broke on my Ender 3 v2. I believe that it was over tensioned from the factory. When I initially assembled the printer, I noticed that the Y-axis tensioner was tightened almost all the way. The belt itself felt very stiff. The X-axis belt, which I installed upon assembly, didn't require a lot of tightening. I have ordered replacement belt material and clips to make new belts.
What is the proper tension for both the X- and Y-axis belts?

they should have a little sound when pulled at.

Generally, a timing belt is a complicated device and many things depend on its internal construction and materials (it may be damaged when bound in wrong direction, or when cut, and when overtighten of course, etc.). There is also physics and math applicable, based on Mersenne's laws.
Some vendors provide calculators (online or as phone apps), which can calculate tension (force in Newtons or lbs) or the frequency (Hz). Therefore often the advice is to tension the belt until some (bass) sound is present - and professionals would tune belts with a sound tuner. There are also hints that belts should be possible to connect with fingers with slight or significant pressure (so not consistent). There is also visual guideline: when you slowly move the carriage with hand, the belt should remain straight. (Slowly, because belt is elastic and may behave different when moving carriage stronger and faster against friction of pulley.)
I would suggest to read this article on 3dprintingspot.com for many practical suggestions.

Mine came from the factory tight enough that it doesn't sag at all, but not so tight that it feels hard or stiff or difficult to deflect a bit with gentle pressure. With the bed pushed all the way to the back, I can push the y-axis belt to the side about 1/8" with gentle pressure, and it feels like that's about as far as it's going to go even if I were to push harder. Seems to work really well without a lot of unnecessary force.


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How to make a replacement belt for Ender 3 v2?
I need to replace one of the belts on my Ender 3 v2. I have ordered the timing belt and crimp ends to make a new belt but I am wondering what is the best way to make a new belt.
I was thinking of making one end of the belt with the crimp end, slotting it in place then running it through the pulleys and pathway until it reaches the other slot. Of course, I would adjust the tensioner to able to tighten the belt. Once I have a taut length, I would cut the belt and add the second crimp end. Finally, reassemble everything and tension the belt accordingly.
Am I missing anything that I should do? Is there a better way to make a belt?
(I opened up one of the "crimps" and it looks to be a 7mm diameter tube that had the belt inserted into it. The crimp was flattened onto the belt then folded in half. The metal is harder than brass or copper. It took considerable effort to open up.)
These are the original belt ends.

There is usually a message printed on belts not to crimp them... Please provide a photo of the old situation (to understand what the old situation was) and the crimped version for people to comment on. I usually make sure the belt is perfectly aligned with the axis and it is clamped in (for a different printer, I usually use a printed toothed attachment piece).

Those are standard crimps and the standard method creality uses. Brass also is known to work harden

You should just be able to print a belt endstop that slides on from the side and matches the belt tooth profile, if you have access to another printer.

I don't have access to another printer. But I will try and find, or make, endstops once I get my printer up and running.

actually... that is brass - brass hardens if bent and crimped.


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How can I improve dimensional accuracy of a delta printer?
I have a delta printer that I am trying to fine tune. I have printed a 20mm calibration cube and I get the following measurements:

X: 20.5
Y: 20.3
Z: 20.0

How can I calibrate my printer to improve the accuracy of x and y ?

Can you first determine the source of the inaccuracy? It could be inconsistency between layers (having them slightly off from one another) or consistent positioning error causing expansion, or just overextrusion.

I recently calibrated e-steps on the extruder, so I wouldn't think it is due to over extrusion.


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BLTouch not touching bed while leveling
I have an Ender 3 Pro that I installed a BLTouch sensor on. After I auto-home, I level bed and it deploys the probe in the right spot, but doesn't go down far enough, then goes back up and stops leveling.
I am using the wiring for BLTouch for Z homing on SKR mini E3 v1.2. I am using Marlin Bugfix-2.0 with BLTouch and a few other things enabled.

Configuration Files
Video of Problem

I think I fixed everything. What I did is I used this guide <youtu.be/y_1Kg45APko> which was a guide by makes'n'breaks on setting the probe z-offset using pronterface and then reverted to the original firmware that was on this page<github.com/bigtreetech/BIGTREETECH-SKR-mini-E3/tree/master/…> Which was the marlin firmware for bltouch for z homing for my mainboard.


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Will RAMPS able to control 4 stepper motors
I am making a DIY 3D printer based on the Prusa mini. So, I doubt whether RAMPS can control only 4 stepper motors as it has slots for 5 stepper motor slots and one will not be used in my case. If I can, in what order should I connect the drivers and also how will Marlin figure out which slot the extruder is connected? Sorry for the lack of knowledge if it is really obvious  :|

RAMPS capabilities
To be more speficic: RAMPS board (versions 1.3 - 1.6) offer possibility to connect 5 stepper motor drivers (on the board marked X, Y, Z, E0, E1) and 6 stepper motors, because the Z axis motor's connector is doubled (this is classic design of reprap printer). I could also see other RAMPS versions/clones (1.6+, 1.7 prototype) which have doubled connectors for X and Y axis motors - so allowing 8 motors in total.
Firmware configuration
Marlin firmware allows to setup in Configuration.h the motherboard with RAMPS configuration (extruder, fan, bed, etc.) and number of extruders. Look for lines:
#define MOTHERBOARD BOARD_RAMPS_14_EFB

#define EXTRUDERS 1

Firmware behavior
RAMPS wiring (as in diagram at Tom van der Zanden's response) is reflected in Marlin's file pins_RAMPS.h. When EXTRUDERS is set to 1, Marlin will use E0_..._PIN setings from this file to communicate with proper stepper driver board (and the driver will communicate with the motor).
Marlin will enable steppers only when required (for example it will not refer to E1 in the basic configuration). Even when they got idle, they will remain powered for some longer period, defined in Configuration_adv.h:
#define DEFAULT_STEPPER_DEACTIVE_TIME 120

Important remarks
Be careful installing drivers and cables. Double-check the driver board's orientation in slot of RAMPS. Solder cables properly, mount them tightly, fix to the frame, etc. Use ceramic or plastic screwdrivers for motor power regulation (I bought one which doesn't fit well, and sculpted my own from 2.85mm filament). It is important to remember to never unplug powered motors and drivers. (There is LCD menu option "Motion > Disable steppers", but I always power off the machine to do something. Also, I had non-intentional accidents of broken wires causing unreliable work of extruder, and fortunately the board survived.)

There is no problem with using 4 motors instead of 5. The 5th slot is provided to enable use of a second extruders, but many people only have a single extruder printer and leave the 5th slot unused.

how will Marlin figure out which slot the extruder is connected

Which stepper motor is in which slot is something you can configure in the firmware. There is no way for the firmware to "figure it out" without help.
It is quite involved to change it in the firmware, so it is best to follow the default placement. You can easily find wiring diagrams for RAMPS (showing the default assignment of motors to slots) on various resources such as the RepRap wiki.


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Considering size of smooth rod
I am making a DIY 3D printer based on the Prusa MINI. I want to ask what smooth rod size is great for a printer with a 20x20x20 cm print volume. I am planning on using a 8 mm rod for the z-axis and 6 mm rods for the Y and X axis. I chose this as I am using a 2.5 kg.cm stepper motor for all the axis, so the X-axis needed to be light and the z-axis needed to be stronger and I chose 6 mm for the Y-axis as it is cheaper then other widths. I am worried if 6 mm is too thin to hold the hot-end (Which is a Bowden type) on the X-axis and a 20x20 cm glass plate on the Y-axis.

Are you on a budget? Linear rails would be very interesting for such a printer, it is not "strength" you should worry about, but "stiffness"! If you want to copy the Prusa model, copy it, not make changes, if thinner rods where giving the same performance, the manufacturer already would have switched to that. Note that the Prusa MINI is completely open source.

Thanks ❤, Yes I am on the budget, and I had already checked the price of those, and they are more expensive that the whole 3D printer. I just checked the prusa documentation, and it uses 10mm for the z-axis and 8mm for the Y and X axis. I might do as you said, but I am worried if the 2.5kg.cm stepper motors I am using can handle the weight of two 8mm rods and the prusa uses a 5kg.cm steppers. I am not really copying the prusa, I am just basing it on the axis design

Linear rails or at least Open-V-Slot are much stiffer than any rod can be. Note that a full TronXY X1 set comes down to about 150 €, but lacks a heated bed.

Thanks @Trish ❤, I kept open-v slots away as they need more parts and need to be more accurate in the placement than rods, and might cost more.


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Can we apply more voltage to a PCB heated bed to get faster heating?
From my understanding, the power of heater must higher than heat dissipate to ambient air so the bed can heat up. The reason why a bed heats up too slowly is due to its heat capacity compared to heater power.
As the heater is a resistive load, I think we can put higher voltage to get more heating power.
The PCB heater has two parts: copper and laminate. The reason of failure is that the copper can come off the board due to high temperatures. In this case we can control temperature with firmware. The questions are:

Will this method work?
What can go wrong or what is the risk of this method?

Yes, this method will work. Some (LED) power supplies have a small potentiometer that you can use to slightly adjust the voltage. On a 12 V printer, adjusting the supply from 12 V to 14 V will give a 36% increase in power.
Obviously there is a limit to how much you can increase the voltage. The voltage itself is unlikely to be the limiting factor, but there is a limit to how much heat the bed can dissipate.

The PCB heater have 2-part copper and laminate. the reason of failire is the copper go off the board due to high temperature. In this case we can control temperature with firmware.

This is true, but you have to consider that firmware is not infallible. If you increase the voltage (and thus wattage) of the bed a lot, you risk creating a dangerous situation if something fails. Ideally, you should choose the wattage of the bed such that it does not create a dangerous situation even if it is left on permanently by accident. In extreme cases (e.g. 220V to a nominally 12V heated bed) damage will be almost instantaneous before the firmware can intervene.
You also have to consider that increasing the voltage also increases the current. The wires need to be thick enough to handle the additional current. You also have to pay special attention to the MOSFET that is used to switch the bed; it also needs to be able to handle the current (and voltage, though this is usually less of a problem). Usually the integrated MOSFETs on 3D printer control boards can only handle about ~10 A which is what the bed might normally draw. Also pay attention to fuses and to screw terminal connections. They might not be able to handle the increased current either.

What about AC heated bed(Orange silicone pad)? Why it can heat much quicker?  I thought it’s had more power per area so I think add more voltage to PCB bed. And about safety My heated bed got about 100 degree centigrade when permanently connected to supply. If silicone pad got higher wattage what happens when we left them connected?

@Mlab Centigrades is hundreds of a grad(uation) and an angular unit. It can also be a reference to any 100 graduation scale, for example Fahrenheit is a centigrade scale. While commonly referred to as a temperature, it is scientifically no longer accepted to speak of °C as centigrad: Temperature is commonly measured in Kelvin, or in the derivate scale K+273.15, aka Degrees Celsius. Do you mean "My heated bed got to about 100 °C / 373.15 K"? That would be beyond the rated temperature range for any heated bed for consumer products. Why do you need a heated bed that operates abve 80 °C?

The reason the AC bed heats faster is indeed because it has more power (per area). If you leave it connected it will reach a higher temperature, roughly proportional to the power (i.e., 2x more power will result in 2x the temperature rise -- a 100 W bed might reach 100 °C (80 °C above ambient) then a 200 W bed will reach 180 °C).

@TomvanderZanden we enforce SI formating on units, so we also should enforce talking about them in terms of SI units or derivate units.

Sorry for making that confusing. I refer to Degree celcius.
@TomvanderZanden I know that for silicone pad the final temperature will higher because of higher power per area. but with your answer " Ideally, you should choose the wattage of the bed such that it does not create a dangerous situation even if it is left on permanently by accident" So  that mean silicone pad can handle higher temperature when silicone pad left connected right?

@Mlab No, not necessarily. A lot of the silicone heaters will create a dangerous situation if left connected. With these, it is a good idea to include a thermal fuse.

Not necessarily
Potential differential U, aka Voltage of a part, is not to be ignored: a 24 V part needs only 24 V, not 36 V. A 12 V heartbeat is only safe for 12 V. There is a little tolerance for those measurements, but rule of thumb is about 10-15% of the rated voltage, so a 12 V bed should not be operated at more than 13.8 V for an extended period.
What actually facilitates heating is the Current I aka Amperage going through an item, as the formula for the Work Ph (dissipated in the shape of heat) of the electric resistance R is $P_h=R I^2$.
As long as you stay below or at the maximum rated Power Pr or Wattage of the heating pad $P_r=U I$, you can increase the Current up to the limit of $\frac {P_r} U=I$. On the bench, with a regulated power supply, we can use that to get a perfect, maximum output as we want it. But the printer isn't a bench with an expensive PSU, we get only something akin to 12 V out of it, so... what to do?
DON'T route in extra Power!
Yea, in DC circuits we can just add batteries behind one another to get twice the Voltage and push a circuit. Or we can put them in parallel, to sum up the current. But that doesn't work just as straightforward in AC circuits (phase shift between parts has to be taken into account). And routing in an extra pair of wires providing 12 V into an already 12 V part would get us something in the order of 24 V and fry the part. You'd accomplish nothing more than turn your heated bed into a fire hazard or a hunk of scrap!
So straight routing in another 12 V on top of what is rated? NOPE!
Unhooking from the same PSU?
Some printers unhook the bed from the board's PSU, running a (differently) regulated power source. In the best case, it's set up to a Voltage/Current pair that maximizes the bed's heating. In such a setup, the whole heating power runs through a MOSFET that acts as a switch: A signal comes from the board to the MOSFET to allow current to flow. No signal on the Gate of the MOSFET leads to no current reaching the bed and no heating.
However, that is a complicated setup - yet one of the only ways how a "mains voltage bed heater" can be done with a board that runs on 5 V. You also will have to route the high power through a properly rated set of wires and connectors. These thicker wires will need proper strain relief as they need larger bending radii than what is installed before. In other words: you need to know what you do!
Finetuning the power supply to the bed!
In many printers, there's also a less invasive method to finetune the power curve of a bed. usually, there is a Potentiometer that is used to tune the output of the heating wires. Altering the potentiometer's setting with a screwdriver results in the output voltage shifting. $U=R I$ does not change when flipping to AC but U and I became wave functions instead of constants. However, R of a long wire (such as a bed) does depend only on the frequency of the signal and not on either the current nor the driving potential, we can assume R to be constant. So, we know we want to maximize I². So what can we do easily?
A 24 V heatbed has something in the order of 2 Ω and accompanied mainboard in my Ender3 is - according to the labeling - good for about 13 A on the bed output, while a typical 12 V bed runs in the order of 1.2 Ω while such boards typically are limited to 10-11 A. $U= RI$ to the resuce and... Voila: For the 11 A/1.2 Ω case we can tune the potentiometer to get just a smidge below 13.2 V - just at the 10 % point, for the 13 A/2 Ω case is technically safe at 26 V - and still well within the 10% rule of thumb. However, if you have a 1.2 Ω bed and your borard only allows to draw 10 A, then you are limited to 12 V.

(also, wherever in my comment I mentioned voltage or current I meant RMS current/voltage)

Let us continue this discussion in chat.

Typically, going above the %20 power safety margin risks burning out your heater.  For a resistive heater this is about 10% above the voltage rating.  At any rate, increasing the heater voltage shortens the life of your heater.

You can add a boost converter to the bed's power supply. Assuming that you are using an external MOSFET to control the bed (and you should). Verify what the MOSFET's max voltage rating is, then obtain a boost converter and configure it to give a voltage that is 10% less than the max. I once used this technique when driving a 24V hot end heater using a 12V power supply. Be forewarned, however, the boost converter I was using exploded during use one day.

Or you could get an additional higher voltage PSU and use that as the bed's heater. They make them up to 80V I think now.


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Stringing between holes
I am printing out models with holes, the printer makes circular patterns for each hole(which makes sense) but then it also has a string that attaches between each hole. This is unsightly and results in a non-uniform surface finish at the top/bottom of prints.
I am wondering if the string is supposed to be there? I am using CURA on the coarse setting, my machine is direct drive with a 3mm retraction setting. I tried increasing retraction to 6mm but the same thing happened.
When looking at the g-code with a layer viewer it shows the strings but I am not sure if it is only representing tool path or not.
edit:
I just tried printing a retraction tower test and I haven't had any stringing, does this mean it's an issue with CURA?
edit v2:
I looked at the layer path on CURA and these strings are not shown. I am at a loss as to what is going on since the retraction test showed it worked fine but every print with holes has the same problem.

a picture is needed to explain this

I will try another print and post a picture, but basically a line is printed along the tool path between holes even though the line doesn't appear on CURA layer viewer. I assumed it was caused by not enough retraction distance but I use a tower test print and no stringing happened.

I added a photo

This is combing, one of Cura's many horribly wrong defaults. Change it to "not in skin" or "off" to fix it.

also, not leveled with too thick a gap

I leveled the bed manually then used a bltouch, I didn't adjust the z axis since it seemed OK

Ok I figured out how to adjust z offset and saved it. I lowered it a bit using the paper method.

Consider that the string you are seeing is the nozzle wiping across the surface, especially if you are not getting stringing via your test part. As you suggest, it's not unlikely that the layer viewer is showing movement and not extrusion.
Check your z-hop settings as well as the other references in the linked page. Z-hop will drop the bed by the set amount when traveling with retraction.

The other useful reference is combing, which limits the travel of the nozzle to remain within the boundaries of the print and also removes the requirement of retraction. It may leave nozzle traces, although that reference is not in the linked page.

All images attributed to linked page.

thanks, I will try changing these and see what happens.

Your newly added photo tosses my suggestion to the wind. It's obvious that you're getting stringing. Have you checked the nozzle for "hangers-on?" Blobs of filament that wipe across the build plate that aren't directly coming from the nozzle?

Hmm, I thought I fixed it by changing the z hop and combining now I am getting weirder results involving blobs

It's combing. Turn it off.

Thanks, I think I fixed it. It's a number of issues combined. Z hop, combing and I increased my bed temp to 85C for first layer to prevent bed slipping. The circles are small I think following layers resulted in some of them getting lose. I could print a raft, not sure.


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Ender 3 V2 Layer Shifting, No Apparent Reason, Desperate
I first want to say thank you for taking the time to read this. I've been trying to print out some parts for another project of mine. These parts use up around 70% of the bed so they are fairly large, unlike the smaller trinkets and things I normally print.
However, I have yet been able to print one of these larger parts without any layer shifting. The part I've been trying to print is a lid to the bottom of a case. It's square, with rounded corners, about 160mm x 160mm.
It will print the first layer without shifting most of the time. However, upon starting the second layer it will almost have at least one layer shift. I have tried a number of things to remedy this, which I will list further down this post.
The layer shifting seems to be unrelated to jerk, acceleration, bed shifting, and z offset at the very least. There is an audible clunk sound that can be heard when it does this. In the image I've linked, you can see the correct path of the print head through the green arrows. However, upon a layer shift, it follows the path of the red arrows. It never shifts during a direction change, only when it is following a straight path. It's almost as if one of the motors gives up for a second. I am aware the print is under extruded, this is one of my trials hoping it was merely the nozzle clipping against the print.

Allow me to share with you my setup:

I have an Ender 3 V2, with the stock mainboard, stock glass bed, and stock hotend.

I've replaced the extruder assembly with an all-metal one from Creality.

I have the stiffer bed springs. As well as the better PTFE tube fittings and Capricorn tubes.

I've put together a cooling pack on Thingiverse. https://www.thingiverse.com/thing:4644985 The mainboard and hotend fans were replaced with Noctua performance fans that I'll talk more about later.

The hotend assembly is a hero me gen 5 with dual 4010 fans and a BLTouch.

I'm using Smith3D's 5x5 high-speed firmware (Previously the 4x4 high speed).

Now let me share my tried solutions.

I firstly, disassembled the printer, checking all belt teeth and motor gears (which are pressed onto their shafts without a grub screw). Afterward, I readjusted all eccentric nuts to get the perfect amount of tension while maintaining smooth operation on both X and Y axes. I've used brake cleaner and dish soap to remove the grease on the Z-axis lead screw and replaced it with WD-40 dry lubricant.

Continuing, I've releveled the bed and checked all axis operation to ensure it was smooth and without any bumps, hitches, or anything of the sort.

I tightened all the frame screws, hotend screws, fan screws, grub screws. Nothing moves even a millimeter.

The belts were tensioned so that they can be strummed like a guitar string when I move either the hotend or bed to its end stop.

I checked my aftermarket fans to ensure they are working. The mainboard and hotend fan run nonstop at their optimal 12V. The PSU fan turns on and off as it needs to cool the PSU...

The cables are nicely managed in the mainboard compartment and I'm sure that the larger fans provide it plenty of airflow. Not to mention the printer was raised by the use of squash-ball feet.

I have slowed my print speed from 75mm/s to 60mm/s with this print. This means a 30mm/s inner/outer wall along with 60mm/s infill speed and 150mm/s travel speed. Acceleration and jerk are at their defaults: 500mm/s^2 and 10mm/s.

I've adjusted my Z offset so that it slightly under extrudes to prevent the filament from bunching up.

I've calibrated my e steps.

I've formatted the SD card and changed my firmware from Smith 3D's 4x4 high speed to 5x5 high speed.

I've updated Cura to the latest version 4.8 and ensured my hero me home offset is correct.

I've tried moving the model to different corners in Cura and ensured the software's jerk and acceleration control are disabled.

I've checked the bed movement with its clips, it doesn't move easily and both clips have very good tension.

I've checked the stepper driver voltages (I did not change them). E: 1.34V Z: 1.16V Y: 0.99V X: 1.15V.

I have Z hop enabled with a 0.2mm hop, no issues or noises when it moves across the print.

I've purchased a filament dry-box from SUNLU along with a new spool of SUNLU black filament. The dry box has Capricorn PTFE tubing that leads the filament straight into the extruder. There is very little friction inside the tube.

I've slightly tightened the tension on the extruder although I didn't have problems with it skipping.

Again, I'd like to reiterate, nothing is loose on this printer, it doesn't skip when it rapidly changes directions, only when following either a straight or diagonal line. The printer movement is very smooth and near-silent with all of my modifications. It's frustrating to me that I can't solve this problem. I feel like the printer has a mind of its own. I have begun to suspect either the mainboard or something else hardware related is amiss. However, I have chosen not to mess with it until posting this. If you've read through this, I thank you for your patience and time reading it.

Any advice or possible causes to this problem are welcomed. I am at a complete loss and am desperate for a solution.

SOLUTION
Unscrewing the mainboard enclosure and tilting it to allow better airflow like in the picture shown below. This is the same issue as many others.

https://forums.creality3dofficial.com/community/ender-3-v2/layer-shift-ender-3-v2/
https://www.reddit.com/r/ender3v2/comments/kn8u72/layer_shift_investigation_data_and_video/
I appreciate the assistance.

You mentioned a noticeable 'clunk' when it shifts, are you sure it isn't a physical obstruction? You said you checked that all axis run smoothly but are you sure you checked the full extents of the printable area?
Watch carefully when the issue happens, are any of the cables getting snagged on the machine or surrounding workspace? Check under the bed in particular, I've noticed on my Ender 3 V2 the bed will sometimes bump into part of the base if the leveling screws are tightened too far.

I am 99.9% certain there isn't a physical obstruction. When I reassembled the printer I made sure there were none. The bed has no wobble, it's rock-solid, but still easy to move by hand. The X-axis gantry is perfectly level and the hotend assembly glides along the rails with ease. There is some slight tension as it reaches the end due to it stretching out the wires, but nothing that the stepper motor can't overcome. The screws don't come into contact with anything that I can see... The nozzle doesn't make any noise at all while laying down filament or traveling over the print.

I have cable chains that keep them up and away from the print. The belts are snug and the teeth don't touch anything besides the gears on the motor shafts. The Z axis (while having slight wobble) doesn't snag or bind on anything. The layer shifts only persist in the X Y direction. Also, I feel like if there were a physical obstruction, it would have a persistent shift that happens in the same location. However, the layer shifts vary in location and intensity as it prints.

Good points. I just noticed from your image and the helpful arrows that it seemed the y-axis missed a step, which reminded me of some of the collision issues I noticed on mine. From your other tests, does it seem to always fail the same way - where the y-axis seems to miss a step? I wonder if it could be related to that lower voltage on your Y driver but that is beyond my knowledge level.

Funny you mention that... I found a youtube video where they (Creality Rep) are trying to fix a non functioning Z axis, but they probe all the drivers to check voltages. Mine were very similar. https://www.youtube.com/watch?v=erbyJCQDOy8 @ 3:00 Either both of our printers are malfunctioning or I'm just unlucky...

Not sure if you're still actively working on this but my setup mirrors yours almost perfectly, I added an all metal extruder, Micro Swiss hotend, a BLTouch, yellow bed springs and Capricorn tube and got great results but needed more cooling so I changed to the Hero Me Gen 5 using 2 5015 blowers and a Noctua 40x20 fan with a buck converter set to 12 V and noticed I had shifting so I printed 35 mm standoffs and wired another Noctua fan, 80x25. It helped reduce shifting but still not perfect and I as well has combed through every possible issue.


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How to design a DIY printer
I am making myself a DIY 3D printer on a budget. And I don't know how to prototype it or design it. Like, I have already planned the parts. But, I don't yet have planned the structure or how parts should go together. I tried using a CAD software, but learning one to reach a skill that is needed will take a long time. I want to know how others design their printers and learn from that.

Do you have a printer already?

@towe Nope, I don't have a 3D printer already

It'll be almost impossible to build a new printer without some sort of manufacturing machine - another 3D printer, a laser cutter, a mill etc.

@towe Yes true, But I have taken it into account in my plan. Like, for the base, I am just going to use a 40x40 plain aluminium or wood and screw the axis on it. Yes, it is not a most elegant way, but if I screw up the place where something should go, I can just make another hole on the correct spot. This will also not need heavy machinery to cut out the parts

There are lots of ways from mere specifications to designs. Most follow several of the principles below, but designing a printer is not a light undertaking. it's HUGE.
Copy and adapt
The most easy way is to take a known design, for example from the RepRap wiki, and copy it verbatim. But it can easily undergo some adaptions, like different hotends or bed sizes.
Paper sketch & notes
Writing down the specs of some parts is very important to make sure these stay consistent. Paper is also the tool of choice for initial sketches or even finished designs to guide building the actual parts.
CAD
CAD is an almost indispensable tool to map out the placement of parts and combine them. Or later design parts to print. A CAD design doesn't need to be detailed, it can use stand in rough outlines. Only where parts need to be custom-made, details are essential.
Prototype
All projects go through prototyping when groups of parts are built and tested on their own and combined piece by piece. Also, this step is where you finalize the firmware.


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Are all glue sticks PVA-based? How to find out?
I'm struggling with bed adhesion for nylon on a glass bed (122 °C measured) in an enclosed chamber (45 °C near the front, likely more on top of the print bed). I used a glue stick to enhance adhesion, but after around 20 minutes the print comes off the bed.
I tried a no-brand glue stick and a Pritt glue stick.
Now I wonder whether they are suitable for the purpose, because nylon should really be printable in these conditions. Maybe the glue cannot hold those 100+ °C temperatures.
How to find out whether a glue stick is PVA-based and suitable for nylon (or polycarbonate, ABS) printing?

For reference about nylon adhesion, see https://reprap.org/forum/read.php?1,175173

Elmer's apparently doesn't reveal its glue stick contents.  Elmer's has at least four different glue sticks without giving the difference in composition.  You can find glue sticks that specify use for 3D printers.  They contain PVP.  Many wood glues have PVA. PVA may be labeled also as PVAc, or as "VA/crotonates/vinyl neodecanoate copolymer" (for example in hairsprays).
It looks like you will need to search patents to find contents of glue sticks.  Her are examples.
According to Elmer's patent 6268413, Wood Glue Sticks have PVA, but I haven't seen such a thing:
This Elmer's patent has PVA: High-strength adhesive paste and dispenser
Patent number: 6268413
Abstract: The present invention includes a high strength adhesive and includes a dispenser containing a high strength adhesive. The invention is an adhesive composition comprising: (a) water present in an amount of from about 40 percent to about 70 percent by weight; (b) polyvinyl acetate present in an amount of about 15 percent to about 35 percent by weight; (c) dextrin present in an amount from about 5 percent to about 35 percent by weight; and (d) starch present in an amount from about 0 percent to about 5 percent by weight; the adhesive having at least 30% by weight solids, having a paste-like consistency, and having a bond strength greater than about 2000 p.s.i. as measured by ASTM D-905. The adhesive of the present invention has a very workable consistency that is very much like room-temperature butter or shortening used in cooking.
Elmer's patent with PVP: HIGH-STRENGTH GLUE STICK FORMULATION, Publication number: 20110301260, includes water; a defoamer; a bactericide; an oil; polyvinylpyrrolidone; a plurality of polyurethane dispersions; dipropylene glycol n-butyl ether; sodium stearate; casein; sodium hydroxide; and at least one adhesion promoter.
Another Elmer's patent has PVP: Adhesive applicator crayon
Patent number: 6066689
Abstract: Adhesive compositions exhibiting fast cure time in solid form, e.g. in the form of an applicator crayon or glue stick. The adhesive exhibiting polymer of the composition is based on a mixture of critical amounts of high molecular weight polyvinylpyrrolidone polymer, with a lower molecular weight polyvinylpyrrolidone polymer, with water, an organic solvent, and a salt of a long-claim fatty acid, e.g. sodium stearate. Color indicators and other optional ingredients, e.g. mildewcide, can be included.

Not all glue sticks work! The working ingredient of a glue stick is Polyvinylpyrrolidone; a more elaborate answer is found here on question: "Why does hairspray work as an adhesive for ABS?".
There are very good alternatives to glue sticks and hair spray nowadays. Specific adhesion sprays exist for several years now (e.g. Dimafix, 3DLAC, Magigoo for PA, Plasticz, PrintaFix, Dr.Mat, etc.; my personal experience is with the first 2 mentioned, both work for nylon: Dimafix has more tack at higher temperatures > 80 °C, up to 80 °C 3DLAC works perfect).
E.g. Dimafix has a higher temperature application range than e.g. 3DLAC. From the manufacturer can be seen that:

Source: http://www.dima3d.com/en/home/dimafix/
This image shows that the spray has its maximum tack/adhesion at about 120 °C and holds this adhesion level at least up to about 145 °C according to the image.
However, not all glues get stronger with temperature! PVA (also called PVAc) glues soften very quickly, making them good only at low temperature. See "Influence of temperature on the strength of bonded joints" which discloses this graph for PVAc Rhenocoll 3W, 4B Plus:

I think I tested the glue stick at too high temperature (120°C), but anyway yesterday I tried also a hairspray with PVA at 60°C bed temp. and it didn't work for thin areas of a printed part with 3 mm brim. I may try again with 10 mm brim! and with wood glue. But I ordered Dimafix as well. I should have recorded a video...

@FarO A department of the company I work for uses Dimafix for all their prints (I print other materials at lower bed temps, so it has never been my favorite, 3DLAC has better adhesion in the 60-70 °C range according to my experience). Note that also specifically engineered sprays exist for PA (nylon), you could also try Magigoo for PA. I have no affiliation whatsoever! Just sharing my experiences.

Not all Glues are PVA based. There is one glue manufacturer call CGMaxed that makes an alcohol based PVB glue. Sold on Ebay exclusively for 22 dollars per 6 oz. I use it every day when my supports fail to stick or having levelling issues.


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Safe, cheap, heated enclosure solution for New England garage
Hopefully this isn't against the rules as it may fall under "opinion" more than a concrete answer, but I'll ask anyway.
I live near Boston and it gets cold here.  My Ender 3 Pro is out in a detached garage with no heat and I'm pretty sure the garage getting down to about -12 °C (10 °F) has ruined a few prints for me. Also I'd love to print in ABS at home as well and I think I'd need an enclosure for that.
Now, the printer technically already has an enclosure. It's in a box made out of plywood with some clear acrylic doors on the front, but I think the box itself has too much extra room and doesn't retain heat well enough (thin plywood?).
So my question is, for anyone with experience printing in cold environments, what are some cheap/easy ways to keep the enclosure warm, preferably as safe as possible since I can't always watch the print.  I have a small space heater in the garage but I turned it off last night because I wasn't sure how safe it'd be overnight and didn't want to start a fire.
Thoughts on stuff like "reflectix" liners for the enclosure that would help retain heat, small heaters, IR lamps, etc...?  All preferably on the cheap side.

Sounds like you have room to insulate the box.  Some would be envious of your ability to cool with fans when needed.

The easiest step would be to add some isolation on the outside of the box. If you have space inside, there might be a good spot to store some non-flammable insulation, for example rock or glassfiber wool.
A different material might also be possible - firebrick is not only non-flammable but also a very good insulator! about 2-3 inches of firebrick can contain the heat produced by a tempering oven while the outside is cool enough to be safe to touch with gloves.
However, you should install an extra thermosensor for the chamber temperature - and make sure that the printer enters print halt mode once the temperature in the chamber gets above a critical temperature to try to mitigate fire risks and possibly start a chamber-cooling protocol - which might include aborting the print or activating coolers that rapidly cool down the chamber.
As you pretty much are going heated chamber, you might find a spot when you might want to use a flexible hose to pull non-chamber air to supply the parts cooling fan.
Also, possibly relocate as much of the electronics to a compartment separate from the printer's heat chamber to ensure the electronics don't get cooked and can be supplied with cooler air.


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Hotend functioning inconsistently. PID completed normally, heating to quickly or not at all on print start up
I have a Xvico X1 printer which I had previously installed an SKR 1.3 on running Marlin, which was functioning normally.
For Christmas I got a BLTouch, a heated bed and a Raspberry Pi for it, so I also installed a new 24 volt Meanwell PSU to power it.
I believe I have correctly installed and updated the firmware for the BLTouch and the heated bed. However, I am having confusing results for my hotend. I successfully ran a PID, though the values seemed suspiciously high (Kp 17.87, Ki 1.24, Kd 64.41).
So my next step was to run a test print. The temperature for the print was set for 200 °C, but after the bed heated, the hotend quickly got to 200 °C and continued to heat until it hit the thermal runaway limit and shut off. I repeated this 3 times, then decided to call it a night and unplugged the machine.
The next time I tried it I had a different result, instead of heating quickly, when the print was started the temperature dropped from 22 °C (room temp) to 8 °C (error?). I have seen that similar errors are sometimes caused by incorrect heater cartridge, but I changed the 12 V cartridge I had installed to a 24 V cartridge when I changed the PSU. I don't really think it's a hardware issue, but I also feel like the firmware is correct so any help would be greatly appreciated.
I have attached a picture which shows an initial drop (in response to a PLA preheat command), then a spike in temperature (hotend set to 200 °C, I had to manually stop it) then I ran a PID autotune, which completed normally, and received the values listed previously.

Are you sure it is a 24 V cartridge? This awfully looks like a large overshoot due to a wrong cartridge (I've had this once where my cartridges got mixed up in my spares toolboxes). Please measure the resistance of the heater element.

I did not think this was the case, the 12 V has a dimple at the end while the 24 volt doesn't. I checked anyway and sure enough the resistance was 14.7, so I'm still at a loss