Auto_Bed_Leveling: Enhanced G29 command

[Roxy]

Yes! That does look flat. Did you set the number of points for Auto Leveling at 8? I'm not sure there is enough stack space to have that much local storage. I've never pushed it to see where the limit is. But it does appear that the values are fine and the code ran to completion!

[DarkAlchemist]

Yes! That does look flat. Did you set the number of points for Auto Leveling at 8? I'm not sure there is enough stack space to have that much local storage. I've never pushed it to see where the limit is. But it does appear that the values are fine and the code ran to completion!

Yes, it is at 8 for now.

I still want to know how I can tweak X and Y to be sure the probe really is blah blah mm away AND I don't understand what this "Correct +.14 with one clockwise turn." is telling me?

[Roxy]

That 'Correct +.14mm' is for me... I should have deleted that when I crossed your configuration information over to my code base. That is so I don't have to think. If I have a corner that is +.14mm too high, I need 1 turn of the screw to lower it that much.

Can you explain in more detail what you want to tweak on the X & Y? Are you trying to set the X & Y Probe offsets from the Nozzle?

[dacb]

That 'Correct +.14mm' is for me... I should have deleted that when I crossed your configuration information over to my code base. That is so I don't have to think.

Do you still have that code around? For the MakerFarm people who all have M3/.5 screws on our bed, I could imagine printing that correction information for each of the three adjustable screws.

[DarkAlchemist]

Yes, I tried to eyeball it as best as I can but I know I am not 100% spot on accurate but would like to tweak it to be.

[Roxy]

Yes, I tried to eyeball it as best as I can but I know I am not 100% spot on accurate but would like to tweak it to be.

Well, the good news is the X & Y Offsets to the nozzle don't have to be perfectly exact. This is a simple function of the fact the bed is fairly flat to start with. So however much the Z-Axis needs to be compensated as you move around on the bed, the X & Y correction is very very small. Maybe somebody else can jump in here, but mathematically the sin(theta) approaches 0.00 as theta approaches 0.00 And the angle of your bed is less than .5 degrees out of kilter going kitty corner. Just holding a ruler up to the center of the nozzle and where the switch is going to get pressed in both the X & Y direction is going to work fine. And actually... If I remember right, those offsets are used to correct the Z height, not the X & Y. The reason is, where the probe measured is different than where the nozzle is, so it corrects the nozzle height based on how far away in the X & Y the probe is.

If it is working well... More accuracy on the X & Y offset won't help.

[DarkAlchemist]

Well, rightly or wrongly I was thinking that the amount of Z being off is at the point of the probe not where the hotend is at plus the offset from what I say is the X and Y difference and what actually is the difference only helps compound any issues.

edit: I like that it tells me to turn one full turn so how do I put that to use for me and my setup and which corner is that?

[Roxy]

Well, rightly or wrongly I was thinking that the amount of Z being off is at the point of the probe not where the hotend is at plus the offset from what I say is the X and Y difference and what actually is the difference only helps compound any issues.

edit: I like that it tells me to turn one full turn so how do I put that to use for me and my setup and which corner is that?

On the Z-Probe... You can measure the Z-Offset, but it is only a guess. You have to manually fine tune that number because every micro-switch is going to fire at a slightly different place. If it is close, it isn't too hard to watch the first layer to see if the nozzle needs to be slightly closer or further away. I move the Z_PROBE_OFFSET_FROM_EXTRUDER by .1mm at a time until I get it right for however things are screwed together on my extruder. (Every time I take it apart to clear a clogged up nozzle, the value changes... And I have to move it up or down a little to get the number right.) But once it is dialed in... Every print has the first layer go down nice and clean.

On the +.14mm per turn comment... Do you know how many threads you have per inch or per mm on your bed mounting? If so, you can just calculate the number and change the +.14 turns number to what ever you have. But if you have your bed mounted on springs in the corner, you could just take a micrometer and measure the thread spacing. That is where that number comes from. But as it turns out, that number can't be used directly. Here is why: If one corner is up 1mm from the mean, you probably only want to lower it .5 mm because the mean is going to move downward as you adjust things. (I realize it seems like you should be able to move it the full amount downward, but my experience is it is better to move it halfway of what is suggested and remeasure.) It is kind of an iterative process. With 3 or 4 adjustments you should be getting really close.

[DarkAlchemist]

On the Z-Probe... You can measure the Z-Offset, but it is only a guess. You have to manually fine tune that number because every micro-switch is going to fire at a slightly different place. If it is close, it isn't too hard to watch the first layer to see if the nozzle needs to be slightly closer or further away. I move the Z_PROBE_OFFSET_FROM_EXTRUDER by .1mm at a time until I get it right for however things are screwed together on my extruder. (Every time I take it apart to clear a clogged up nozzle, the value changes... And I have to move it up or down a little to get the number right.) But once it is dialed in... Every print has the first layer go down nice and clean.

On the +.14mm per turn comment... Do you know how many threads you have per inch or per mm on your bed mounting? If so, you can just calculate the number and change the +.14 turns number to what ever you have. But if you have your bed mounted on springs in the corner, you could just take a micrometer and measure the thread spacing. That is where that number comes from. But as it turns out, that number can't be used directly. Here is why: If one corner is up 1mm from the mean, you probably only want to lower it .5 mm because the mean is going to move downward as you adjust things. (I realize it seems like you should be able to move it the full amount downward, but my experience is it is better to move it halfway of what is suggested and remeasure.) It is kind of an iterative process. With 3 or 4 adjustments you should be getting really close.

No, I completely understand because if you move one corner up they all change slightly and the opposite corner can change dramatically. My threaded rod is M5 at 0.8 pitch so 1 full revolution moves Z by 0.8mm and my bed is hard mounted so no springs.

So, knowing that what would I change in which file and when it is telling me to rotate something which corner, or what, is it telling me to turn?

[RobH2]

Hey, there is a user here that I'm trying to help out. Any of you know if the autoleveling will work with a Flashforge machine where the bed moves for the 'z' motion instead of the hot end? It seems like it should, it's just reversed sort of.