As always with Lost in Tech videos, you shine a bright light on a topic not well understood by many. And the flow charts! I love the flow charts!

Great video as always man :) I never thought about the fact that z height moving during the first layer helps show the mesh working! Thanks for the tip 😎

The S argument for M420 can be understood if you understand what the manual says. As I recall the online manual says "S". That means the value for the S argument is a boolean value with 1=true or on, and 0=false or off. This (and a lot of the Marlin documentation) is what happens when programmers write documentation before remembering to code-switch from programming jargon to normal vocabulary.

Oh this is great information. Thank you for the clear explanation!

Definitely more videos on mesh bed leveling and Gcode

Hey! I'm a machinist and i use Gcode when I have seen the title I asked myself "wtf is m420?! I have never used it before" and it didn't even crossed my mind that you were talking about 3dprinter Gcode 😂 it was a good surprise!

I kept reading all the code notes hoping there's more jokes than just the first line XD

dude u have saved me!! i was so close to sending my cr touch back! i could not for the life of me i could not get UBL to work! turns out i was missing M420 on my gcode thingy...ur a legend! subbed!

Very Good and Clear Video! Thank YOu!

Great video! I had been trying to add more probing points on my ABL mesh for weeks LOL!

Awesome thank you so much for clarifying all this up for me! I've been pulling my hair out trying to figure out what was wrong with my printer. Come to find out I had no idea my mesh leveling wasn't being saved. Lol. Ya I'm new to all this but learning everyday. Thank you again! Going to go try it out now

I would love more of these videos

Great video!

ROM = Read Only Memory, comes preprogrammed on the chip die. PROM = Programmable ROM, can be programmed ONCE, then that's it. EPROM = Erasable PROM, can be erased with UV light and the package has a transparent window, usually covered with a metallized sticker. EEPROM = Electronically Erasable Programmable Read Only Memory, it's almost static RAM, but less volatile. Still waiting for the next letter to be tacked on the front.

@6:55 The setting ENABLE_LEVELING_AFTER_G28 is what I use, and works perfectly: Every print use the mesh automatically. If you messed with the bed and you find you have to re-mesh, just do a G29 and a M500 to store the mesh and Bob' your uncle..

Great video. I setup my gcode using Jyers guide when I flashed that on my Ender 3 v2 so now I want to verify I have it right

Ahh the old 420 helping people to be happy

M420 (blaze it) S1

M420 ZXX sets your fade height. Hence, at 7:27, your Z will stop moving in between layer heights, after the fade height is surpassed.

I've had a CR Touch installed for close to a year. Somewhere along the way I got messed up with the commands. After your Twitter post last week, I looked into it more. Yep, been creating nice meshes for nearly a year but was not using them 🤣🤷‍♂️ My E3V2 is still a PITA at times, but it's printing better now.

Thank you!!

Please expand on this. I can't believe how little info exists about this. I have installed ABLs on my printers for the longest time not know what the hell is going on

Thank you!

If you have UBL have it build a very fine mesh and on every G29 command add a J argument "G29 J" to do a 3 point probe but 10x each point. In firmware set it up so the outliers get automatically omitted and you will get insane accuracy of course this works best on the most rigid of bed substrates such as glass beds or extremely thick aluminum or steel bed bases.

yeah the s in m420 is boolean operator for g29 is slot operator so its self explanatory after some googlin

Flying Bear Ghost 6 has manual mesh enabled from factory in Marlin 2.x (no ABL in stock configuration)

Yeah, more of these.

Literally can't remember the name of it but, yeah.... I video on how to do a manual mesh would be interesting, I get on well with how you explain Gcode.

great video, I have been struggling with the automatic bed leveling...

I have a cr touch I do the paper test then I print. Once it’s starts printing my nozzle is not where I set it do you think this code will help?

a little help please.can you tell me if this is correct? I have a ender 3v2 with cr-touch,these are my g codes.G28 ; Home all axes G29 P1 ; Home automatically and run mesh leveling on every print

So it's like 42, but with 0! Probably not the 420 joke you've meant ;) Manual UBL looks interesting, it _seems_ possible but reading the Marlin doc about it becomes impossible quite fast. Also as for 00:05, yes.

If I'm understanding this correctly, with ABL (BLT) all you really need is the G29 command AFTER the G28. Even if G28 disables bed leveling, G29 would enable bed leveling and do the bed level, creating a mesh. This mesh is then saved to RAM and used for the current print. Yes, if you turn off printer, this bed mesh is lost, but run the G28/G29, creating a new mesh in RAM and everything should be fine? Is this correct? Thanks! Great video.

I just use klipper, it’s quite useful and does the bed leveling mesh thing

I want to plot the bed leveling (x,y,z) data in a 3d mesh using javascript. How do I export the ABLdata once the machine has collected it? After ABL is done I would connect to the printer with Pronterface and get the 49 ABL data points, to copy them, Is this right? M420 V1 T1 ; export abl data in csv format

So I have been stuggling to find a solution to my auto bed leveling problem and I can't find a solution to it. My problem is I have the CR Touch on m Ender 3 V2 and when it levels, the back left corner and the front right corner are not level even after manually leveling it. The points of measuring are not really that good and far over to 1 side and dont know how to change that but shouldn't give me false measurements. but the problem is the back left corner keeps adjusting upwards thinking its too close and the front right keeps adjusting down almost scraping the bed thinkig its too low. I dont know if the sensor is faulty or of the printer thinks its measuring somewhere else or if its measurements are inverted. I tried updating the software and it doesn't work so currently I disabled the loading mesh and auto leveling in the start code so I have to manually level like before I had it. If you have any way of editing points or measurement or rotate a mesh I would gladly like some help with it.

so if i click bed leveling on the printer, and have m420 in the Gcode. it will load the firmware that the printer just mapped out? is this correct?

Does anyone know m915 or the stall detection

Ender 3 V2 with professional firmware here and no probe (only manual mesh bed leveling)...so I should use M500 after the M420 S1 command?

I use this to load the mesh and do a 3 point level in case my gantry is off a little. With dual Z screws that happens a lot with mine. G29 L0 ; Load UBL mesh values from slot 0. G29 J ; Probe 3 points and tilt the mesh to the plane.

Is there a G69 to go with my M420?

it's like the M211 command to turn on and off soft endstops "S" stands for "Switch" as in "switch on" or "switch off" just like in binary 0=off 1=on so M420 S1 = bed mesh on.

Thanks for the info! So something like below would be redundant, or basically make its own mesh, then load one that you stored from earlier, correct? G28G29 ; Home all axes M420 S1 ; Enable mesh

The ender 3 factory firmware seems to have the RESTORE_LEVELLING_AFTER_G28 option set - but with G29 disabled as I get the message below. They have a different binary for use with a BL Touch, which presumably re-enables the G29 / M420 commands. This seems like a fairly logical way of doing things. >>> G28 SENDING:G28 echo:Unknown command: "M420 S1" >>> G29 SENDING:G29 echo:Unknown command: "G29"

So if I wanna Auto Home -> Create Mesh -> Use Created Mesh I just put G28 -> G29 -> M420 S1 in the gcode right?

I cant for the love of god get my ender 3 v2 neo use the mesh. It just wont move the z axis at all in any layer. I use the G29 after the G28, it does the probing but never uses it. How can I solve this please?

You mentioned it briefly - I have an E3 v2 with the crtouch. is that ABL or UBL?

I think it’s important to mention the fade height as if the bed is poorly trained and no height is set, the printer will recreate the mesh for the entire height of the print, leaving you with apparent z-banding.

Nice

For Bltouch the gcode then is G28 ;home all axes G29 ;ABL M500 M420 S1 ?

Need more Input! I may have to watch this again later at a reduced speed. Haha

It’s interesting that there are scores of ABL videos but almost zero mention M420 and I’ve found only one that is any good- yours.

please do a UBL G29 version.

Awesome. I just realized how much time I've wasted doing bed leveling since the startup gcode in Cura has always had G28 at the beginning; I opened the Marlin configuration file on VSCode just to check, and sure enough, both lines that reload the bed mesh were commented. Luckily, my heated bed is pretty flat so bed leveling has never been crucial, but now I wonder how many defects have been just because of those tiny variations. 🤡

I use G29 or M420 S1 but the compensation don't work, please help me :(

Hi very thorough video, I have what maybe a dumb question, Will a code without the letter work or be ignored? Example M420, will 420 produce same result? Thanks

Can you make video guides for Klipper please.

Sorry, kinda phased out on the explanation (more likely due to me being noob in 3D printing), but all this fancy stuff doesn't apply if I have no auto bed leveling or some sort of electronic bed probe, right? I use paper to do that...

should we do an auto level for every single print we print out ?

Hi! Working with a CR10 Smart. So I added the M420 S1 and checked that Z axis is compensating while printing. Checked X grantry, bed bolds and updated firmware. Any suggstions?

I am having a very strange issue with my modded ender 3 with idex and octopus board. It recently started happening. Is there a way we could chat and I can pick your brain? It's something I think with e steps changing in mid print. But that's just a thought. I like to get into pretty detail

This video kind of confused me further. So, what do I use if I just want it to level before every print, G29 then M420? I've been using g29 as I thought it would auto level before every print but the first layer is not coming out good. I have set the z offset according to another video but I am still getting really crummy first layer with a 16 point mesh.

The M420 S0 confused me for some time. Marlin using S to enable/disable the mesh really seems like a poor decision. So...how do you load a mesh from a specific slot??

It's specifically listed as a command that takes a boolean argument. either 0 or 1 (on/off). has nothing to do with slots.

why doesnt it work for creality? whatever I list in the gcode sequence it will always repeat G29 instead of reading from the saved mesh? It just ignores M420, or it re-levels even if there is no g29 in the gcode. Is there a way to change it?

Can this be applied to a cnc machine for warped wood?

so if you use g29. it will map the bed, and then save and use that mesh right away for the print it is working on?

Should I put M420 before or after G92 because unlike other profiles I’ve seen, my G28 comes first then G92 and I’ve then put in M420 S1 and I’m still having mesh issues

It'd be awesome if you did do a separate video on the unified bed leveling and show us your start g code! Pleaseeee

SOOOOOO ,you maybe able to help me out then , with the Neptune 3 I'm having issues with it saving the Z offset and it may be because of my starting Gcode What would be a good starting gcode for the Neptune 3 since it's not a actual probe but the sensor nozzle thing probing the bed ??

1:40 artillery hornet does it this way and i love it ….. that printer is stupid fast for an ender like machine and i didn’t want to add any weight on the printhead with a BL touch

Why dont they use a method that purges more on lower areas only on the first layer instead of moving the z axis for the complete print

Wait, auto bed levelling doesn't do anything unless you have m420 in the start gcode? A'd the mesh gets removed every time I turn off the printer? This is a confusing video.

Thank You! Subscribed.... Why is this info so hard to find???

i do have one question.. why do have 100 probe points but it only ever gets to 57??

Can a printer print without a nozzle? Could you test that?

Please sir teach me what UBL/ABL mean

great video bro, but please there is absolutely no need of annoying background music. We are here to listen to what you have to say.

P = programmable

G28 clears the mesh 0_0?!?!!

420 haha

Stay in Cura 5 (has Z-offset... !!!) Good for 90% of 3DP Users ! Marlin is machine code intensive, If your an engineer, Rock Out, otherwise dont kill yourself with needless overcomplication ! Great video ! ~liked ~subD

0:48: NOT AN ACRONYM ... Acronyms are a subclass of initialisms that are pronounceable as their own word. ABL is not normally referred to as "able" nor is UBL normally referred to as "ooble", and MBL is possibly only pronounceable as a word in languages like Welsh. Therefore, these terms are spelled out when spoken and each letter refers to the first letter of an actual word, so it's A, B, L, for example, and therefore they are initialisms. Now, let's talk about the signs at the market checkout station that says "15 or less" ... So many English ignorant people (sadly, usually a result of American public education). SMH.

I think you dont teach good because you just talking please put much more picture and tell me what should we do you other channels doing like this and they are hekp to solve our problems