Bed not level after bed level correct  

Re: Bed not level after bed level correct

Well, that looks to be more than the bed level correction settings could cope with. Can you use a piece of glass or a straight-edge to determine whether your bed is indeed flat? Is it possible that your X-axis rods are warped or that you've tightened the bed too much in assembly?

Re: Bed not level after bed level correct

Thanks David for the reply. So i have already checked for a a warped bed and got a a replacement since my old bed was warped. When you say check the x axis how do i check if it is warped. Finally which screws do i check the ones holding the bed to the y carriage or the screws holding the y carriage to the hardened steel rods. 😀

Re: Bed not level after bed level correct

After changing the screws on the bed and y carriage the bed level is still uneven and unchanged. The x carriage is level as the rear side would be unlevel to but it is not. Thanks

Re: Bed not level after bed level correct

Connect pronterface then carry out a calibrate z from the LCD menu on the printer, dont use g80 from pronterface.
The printer will drive up an set the z level the same for the 2 screws then tell you to clean the nozzle etc and carry out a 9 point level check.
When this has finished type G81 from pronterface then use this to check you bed and adjust as necessary (If you have fitted springs or wave washers etc).
Note: sometimes the two screws dont home together properly and you end up with a skewed bed shown from left to right with one side higher than the other by about 0.1mm, if this occurs, just run the calibrate z again then the G81 and see that the data changes, you should see the 4 corners all being about the same height and the middle slightly higher or lower ideally the same as the corners, but I think your patience will give up.
You will find a thread where I have been struggling to get a flat bed, but this is what I have just managed.

0.00250 0.01093 0.01676 0.02000 0.02065 0.01870 0.01417
0.01407 0.01828 0.02115 0.02269 0.02288 0.02174 0.01926
0.02074 0.02282 0.02412 0.02463 0.02436 0.02331 0.02148
0.02250 0.02454 0.02565 0.02583 0.02509 0.02343 0.02083
0.01935 0.02344 0.02575 0.02630 0.02507 0.02208 0.01731
0.01130 0.01952 0.02442 0.02602 0.02430 0.01927 0.01093
-0.00167 0.01278 0.02167 0.02500 0.02278 0.01500 0.00167

Not bad at all now.

Re: Bed not level after bed level correct

Oh I then carried out a G80 G81 run and got this:
0.13083 0.13944 0.14500 0.14750 0.14694 0.14333 0.13667
0.14630 0.15401 0.15827 0.15907 0.15642 0.15031 0.14074
0.15602 0.16284 0.16608 0.16574 0.16182 0.15432 0.14324
0.16000 0.16593 0.16843 0.16750 0.16315 0.15537 0.14417
0.15824 0.16327 0.16531 0.16435 0.16040 0.15346 0.14352
0.15074 0.15488 0.15673 0.15630 0.15358 0.14858 0.14130
0.13750 0.14074 0.14269 0.14333 0.14269 0.14074 0.13750

Way different and showing a larger hump in the middle, but I had already checked the lead screws for turning whilst moving the head in the X direction and the bed in the Y direction so knew the bed is flat.

After that I carried out a complete factory reset selecting All Data to wipe the EEPROM and basically recalibrated the complete printer but now it has calibrated with the 4 bed calibration points level.
I know now that any stored values used for automatic levelling are going to be as accurate as possible.
Also interestingly, my Live-Z value has come right down from about 1.3 to 1.15

Re: Bed not level after bed level correct

Thanks for replying how about these numbers
0.03583 0.04704 0.05759 0.06750 0.07676 0.08537 0.09333
0.01056 0.03655 0.05591 0.06861 0.07467 0.07408 0.06685
-0.00750 0.02032 0.03967 0.05056 0.05297 0.04692 0.03241
-0.01833 -0.00167 0.00889 0.01333 0.01167 0.00389 -0.01000
-0.02194 -0.02940 -0.03644 -0.04306 -0.04925 -0.05502 -0.06037
-0.01833 -0.06289 -0.09632 -0.11861 -0.12977 -0.12980 -0.11870
-0.00750 -0.10213 -0.17074 -0.21333 -0.22991 -0.22046 -0.18500

Re: Bed not level after bed level correct

After a couple of changes the numbers have changed to these
-0.03083 0.00750 0.04500 0.08167 0.11750 0.15250 0.18667
-0.04602 0.00705 0.05350 0.09333 0.12655 0.15316 0.17315
-0.05157 0.00328 0.04983 0.08806 0.11797 0.13958 0.15287
-0.04750 -0.00380 0.03398 0.06583 0.09176 0.11176 0.12583
-0.03380 -0.01419 0.00597 0.02667 0.04791 0.06970 0.09204
-0.01046 -0.02789 -0.03422 -0.02944 -0.01357 0.01341 0.05148
0.02250 -0.04491 -0.08657 -0.10250 -0.09269 -0.05713 0.00417

RE: Bed not level after bed level correct

Hi, I know this is an older thread but I'm hoping you guys can help me sort out my printer. What is going on is the back side of the printer is staying lower than the rest of the bed even after mesh bed leveling correction. One odd thing is this just started happening (had my MK3s for a year or so). I tried the mesh bed calibration correction and that did not work even maxing out the back to -100 microns. I also tried 3x3 and 7x7 meshes with no changes. I also cleaned under the sheet, and swapped sheets with no changes. 

I think maybe physically tuning the bed is a good next step so that is why I am here. I followed the process of using the calibrate z (on the lcd) to get the z lead screws aligned then I used the G81 command in pronterface to get this result:

0.03083 0.10407 0.16380 0.21000 0.24269 0.26185 0.26750
0.07398 0.11927 0.15773 0.18935 0.21415 0.23211 0.24324
0.09676 0.12331 0.14760 0.16963 0.18939 0.20689 0.22213
0.09917 0.11620 0.13343 0.15083 0.16843 0.18620 0.20417
0.08120 0.09794 0.11520 0.13296 0.15124 0.17004 0.18935
0.04287 0.06853 0.09291 0.11602 0.13785 0.15841 0.17769
-0.01583 0.02796 0.06657 0.10000 0.12824 0.15130 0.16917

I can't seem to find what these numbers mean, I assume they are coordinates but which is for what axis? I found the link to a visualizer ( https://pcboy.github.io/g81_relative/) and it spit out this:

Raw values:
-0.12 0.06 0.12
-0.05 0 0.05
-0.17 -0.05 0.02

Degrees:
86°CCW 43°CW 86°CW
36°CCW 0 36°CW
122°CCW 36°CCW 14°CW

Fractional Turns:
1/5CCW 1/10CW 1/5CW
1/10CCW 0 1/10CW
3/10CCW 1/10CCW 0CCW

My plan is to buy very thin washers from mcmaster car to level out the heated bed, I'm just not sure how to interpret the mesh output. Any advice would be helpful, eager to get printing again.

RE: Bed not level after bed level correct

have you run the z axis all the way to the top, reset the printer and run the z axis to the top again, so that the X axis end pieces stall against the Z top brackets on both sides?
then recheck live Z... ?

the plotting  information is for the 49 test points of the 7x7 mesh bed levelling. 

the two lots of information following are the adjustments are for adjusting the bed, around the centre screw

this information is intended for use with either springs, silicone tubes or nyloc nuts to level the heatbed mechanically

regards Joan

RE: Bed not level after bed level correct

I went the route of washers to shim the bed.  It was a total complete waste of time. It sort of worked, but I eventually removed them and replaced the one ferrule I had filed down a thousandth.

In time I think I realized the bed really wasn't that "off" - that is was a flaw in how the PINDA works and is temperature sensitive and how the bed was warping or not warping with various temperatures.  I now have a bed compensation of -50 um for one side of my bed, done in the menus, and I get very good layer one across the full bed. Not perfect, but good enough for full bed prints.

The trick is to only start the bed level when the PINDA is at a defined temperature. And this can be done with gcode.

However, if you do want to dial in the bed to perfection, I'd recommend the "Nylock Mod" over washers. The concept is simple: you place a nylock nut on the back of the fiberglass heater, snug it up so the screw and nut are semirigid but can still turn. You then install the heat bed, and can now turn each screw into the frame. Slowly lowering it to the proper height. Some use the center ferrule as a reference, lowering the bed until that center screw is tight. You can then turn the outer screws as needed to raise or lower the perimeter to make the heat bed as level as you want.

Octoprint has a plug-in that turns the bed level figures you posted into a 3d view to make the process easier.  But - be prepared to chase this in circles if you also don't use a set PINDA temp every test run.

RE: Bed not level after bed level correct

Here's a view of a worksheet I created to use the measurement dump - emulating what the Octoprint plug-in does.

 I recommend Octoprint: https://plugins.octoprint.org/plugins/bedlevelvisualizer/

pps: if you believe the numbers, my bed was off nearly a millimeter. Which - in the end - it wasn't.

RE: Bed not level after bed level correct

Ah Joan, thank you. So you are saying that these are absolute heights for the 7x7 mesh bed. In my case 0.03083 would be the back left and 0.16917 would be the front right? Do I have this correct.

Rather than springs I wanted to use thin washers to manually level the bed, but 0.5mm is the thinnest washer I could find so maybe this is too large.

Anyway I tried running the z axis up to the top on both sides then reset the printer (by reset I'm assuming you mean the x button). I then printed a 9 square calibration .stl and the print actually failed on the front left square, part of that is that pla doesn't stick well to my textured bed (and I'm printing inside so I didn't want to use my normal abs). Anyway I realized that the area I'm having issues with is in the back right quadrant, but not exactly the back, see attachment. I'm going to try the print again tonight after running up the z axis manually.

I got the 7x7 data back from pronterface and it was very similar. Doesn't calibrate z to the same thing as manually running up the z axis?

0.01000 0.07889 0.13750 0.18583 0.22389 0.25167 0.26917
0.05157 0.09868 0.14001 0.17556 0.20532 0.22930 0.24750
0.07491 0.10655 0.13566 0.16222 0.18624 0.20773 0.22667
0.08000 0.10250 0.12444 0.14583 0.16667 0.18694 0.20667
0.06685 0.08652 0.10637 0.12639 0.14658 0.16695 0.18750
0.03546 0.05862 0.08143 0.10389 0.12600 0.14776 0.16917
-0.01417 0.01880 0.04963 0.07833 0.10491 0.12935 0.15167

Raw values:
-0.14 0.04 0.12
-0.07 0 0.06
-0.16 -0.07 0.01

Degrees:
101°CCW 29°CW 86°CW
50°CCW 0 43°CW
115°CCW 50°CCW 7°CW

Fractional Turns:
3/10CCW 1/10CW 1/5CW
1/10CCW 0 1/10CW
3/10CCW 1/10CCW 0CCW

RE: Bed not level after bed level correct

@tim-m30

Hi Tim, this sounds intriguing to me. I'm not after perfectly level so maybe I am barking up the wrong tree. Full bed prints is all I am after, can you elaborate on how to set the PINDA temp in gcode, I did a quick google and found a lot of opinions. What warms/cools the PINDA? I live in Colorado and see a lot of hot and cold days. I use an enclosure, but in a non-heated garage so temperature control is a constant problem for me.

RE: Bed not level after bed level correct

Perhaps it will be best to simply ask what you are trying to achieve.  If chasing numbers, you are on track to do that for a very long time. If you just want to print, then post a photo of the print issue you are having.

Use the startup gcode below, and print out a set of test coupons (there are several 9 x 9 test prints out there, and I've attached a simple set). By looking at the actual layer one pads, then adjusting bed level compensation may be enough.

TestPads

The PINDA sits is free air, mostly. So anything around it will warm it up: the bed, the nozzle, the room... but mostly the bed and nozzle. Since you might start a print from a cold start; or you might start a print immediately after a long ABS print, the PINDA temperature can swing wildly. A 10 degree temp difference in the PINDA will affect Layer 1 dramatically. 

Here's my 'stabilize the PINDA' startup gcode. It also reduces oozing before printing by preheating the nozzle to a lower temp. Red highlights the PINDA control section - but other things are happening in there, too.

M115 U3.9.1 ; tell printer latest fw version

; printer specific Printer Start Gcode
M862.3 P "[printer_model]" ; printer model check
M862.1 P[nozzle_diameter] ; nozzle diameter check
{if print_settings_id=~/.*(DETAIL @MK3|QUALITY @MK3).*/}M907 E430 ; set extruder motor current{endif}
{if print_settings_id=~/.*(SPEED @MK3|DRAFT @MK3).*/}M907 E538 ; set extruder motor current{endif}

; generic Printer Start Gcode
G90 ; use absolute coordinates
M83 ; extruder relative mode

; M104 = set hot end temp
; M109 = wait for hot end temp <Sxxx and Rxxx interchangable>
; M140 = set bed temp 
; M190 = wait for bed temp <Sxxx ignores too hot, and Rxxx waits for heats or cools as needed>

; cool down PINDA
M106 S255 ; turn on fan
M104 S0 ; turn off nozzle heat
M140 S0 ; turn off bed heat
M860 S35 ; wait until PINDA is less than 35C
M106 S0 ; turn off fan

; preheat nozzle to a low temp, get plastic mushy before driving into the bed with G28
M140 S[first_layer_bed_temperature] ; set bed temp
M109 R175 ; wait for extruder temp
M190 R[first_layer_bed_temperature] ; set & wait for bed temp
G28 W ; home all without mesh bed level

; soak PINDA then level
G0 X50 Y50 Z1 F3000; this is a good PINDA heating position
M860 S37.5 ; wait until PINDA is >= 35C in winter, 37.5C spring/fall, 40C summer
G80 N7 R5; mesh bed leveling

; heat to extrude temp
G0 X0 Y-3.0 Z10 F3000; this is a good nozzle heating position
M109 R[first_layer_temperature] ; set & wait extruder temp

; purge
G1 Y-3.0 Z0.20 F1000.0 ; go outside print area
G92 E0.0
G1 X1.0 Y-1.0 E0.5 F500.0 ; scribble 1
G1 X1.0 Y-3.0 E0.5 F500.0 ; scribble 1
G1 X2.0 Y-1.0 E0.5 F500.0 ; scribble 2
G1 X2.0 Y-3.0 E0.5 F500.0 ; scribble 2
G1 X3.0 Y-1.0 E0.5 F500.0 ; scribble 3
G1 X3.0 Y-3.0 E0.5 F500.0 ; scribble 3
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.0 F1200.0 ; intro line
G1 X97.0 F2000.0 ; wipe left
G1 X105.0 F3000.0 ; wipe right
G92 E0.0

; reduce extrusion rate for larger layer heights
M221 S{if layer_height<0.075}100{else}95{endif}

; end Printer Start Gcode

RE: Bed not level after bed level correct

@jessebaker09

Hi Jesse, 
I have never personally done the Nyloc method, or springs, wave washers or silicone sleeve adjustments, so I am not a good reference to which number is which point on the bed...  (Have a look at the i depth threads)
I did try variable thickness spacers, but that didn't end well, so I went back to original spacers
in the days before 7x7 Mesh bed levelling, I did use 'bed level correction' which allows you to adjust Front, Back, Left and Right sides, relative to the centre of your build plate (to address a corner you could adjust the two adjacent sides). but since 7x7 Mesh bed levelling I haven't used that feature. 

regards Joan

RE: Bed not level after bed level correct

@tim-m30

Hmmm.... The fact that the PINDA doesn't have a defined heating or cooling source is a bit frustrating. The way your g code is written seems like you are walking a tight balance of keeping the PINDA at the right temperature and your extruder/bed at material temps. I might want to try something simpler like what I have below. I'm assuming that since I typically print ABS the heatbed/extruder will get my pinda probe above the set point temp and if I move the extruder up 150mm with the fan on it will cool the PINDA without me having to turn off my extruder/bed. Since I am fighting cold temps right now in the winter I have to manually sit through the warmup process so I'm trying to reduce startup time. Do you think this looks ok?

G0 X50 Y50 Z1 F3000; Set position to ensure PINDA heats up with bed/extruder
M104 = set hot end temp
; M109 = wait for hot end temp <Sxxx and Rxxx interchangable>
; M140 = set bed temp 
; M190 = wait for bed temp <Sxxx ignores too hot, and Rxxx waits for heats or cools as needed>

G0 X50 Y50 Z150 F3000; Lift nozzle to 150mm to cool PINDA
M106 S255 ; turn on fan max to cool PINDA
M860 S37.5 ; wait until PINDA is 37.5C
M106 S0 ; turn off fan

As far as the print I have been struggling with my immediate problem seems to have gone away. You can see I produced another failed print, see attached. But this peeled up because I used the prusa recommended 105 bed temp for abs, which from my experience is too low. I watched the first layer and it was pretty darn good, it also peeled from the left side rather than the upper right like before. Right now I'm 80 percent into a good print with the proper bed temp. I'm going to do some A/B testing when I have time on the PINDA settings. Thank you for the test pad .stl.

One clarification on the M860 S37.5 command, I'm a little confused. It seems like this command just waits til the PINDA hits your set point whether it is increasing or decreasing to s37.5. If so it seems like there is a chance it would time out because you might be trying to cool the PINDA when you are below your set point or trying to heat it when you are above it, if either of those happens you will never hit your set point. This is where I wish there was a dedicated heating or cooling point for the PINDA, maybe I need to design a duct.

RE: Bed not level after bed level correct

Won't work for a few reasons I don't have time to go into... but good luck trying.

RE: Bed not level after bed level correct

Alright so I think I am close, can someone look at this? I highlighted in red what I added to the start up g code. When monitoring my PINDA gets up to 50C, so that part is good. I also got my extruder to raise from the bed and the fan to come on, but my "M860 S37 ; wait until PINDA is 37C" command doesn't pause the hotend to cool the PINDA, it just proceeds to home and start the print. Any ideas?

M115 U3.7.2 ; tell printer latest fw version
G90 ; use absolute coordinates
M104 S[first_layer_temperature] ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
G28 W ; home all without mesh bed level
G0 X100 Y100 Z5 F3000
M83 ; extruder relative mode
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S[first_layer_temperature] ; wait for extruder temp
G0 X0 Y0 Z150 F3000; Lift nozzle to 150mm to cool PINDA
M106 S255 ; turn on fan max to cool PINDA
M860 S37 ; wait until PINDA is 37C
M106 S0 ; turn off fan
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
G1 Y-3.0 F1000.0 ; go outside print area
G92 E0.0
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line
G92 E0.0
M221 S{if layer_height<0.075}100{else}95{endif}