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Problem with the auto bed leveling (IR probe)

Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
Hello everyone,
I am Chris from Austria and I have some problems with the funktion of my IR probe on my A5.
Everything is working but when my probe does a measurement I got for example that:

LESEN: Bilinear Leveling Grid:

LESEN: 0 +0.486 -0.046 -0.089 -0.378

LESEN: 1 +0.040 -0.001 -0.086 -0.044

LESEN: 2 +0.004 +0.094 +0.158 -0.050

LESEN: 3 -0.086 +0.004 -0.115 -0.236

Offset is at Z-3.3    But when I try Z0 in different spots the high is not at 0.2mm as i want.
For example now on the left front the nozzle is in the high and on the right i crash.... WHY is that so?
I tryed turning off the light and everything but that goesnt change anything...

Can anyone help?

Best regards,
Chris

Comments

  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    I am not sure but I think there is a problem with the metal clamps of the plate.
    I changed the max of the measurement range to:
    #define LEFT_PROBE_BED_POSITION 20
      #define RIGHT_PROBE_BED_POSITION 285
      #define FRONT_PROBE_BED_POSITION 30
      #define BACK_PROBE_BED_POSITION 270

    and got that result:

    LESEN: 0 -0.061 -0.179 -0.092 -0.180

    LESEN: 1 -0.080 -0.043 -0.009 -0.185

    LESEN: 2 +0.047 +0.077 -0.179 -0.134

    LESEN: 3 +0.036 -0.186 -0.021 -0.076

    Looks better to me
    I keep you in touch...
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    Same situation and more measure points, bad result (my plate is stratched because of that measure problem in the middle, you can see that even in the result of the measurement)

    LESEN: 0 -0.060 -0.197 -0.146 -0.074 -0.196

    LESEN: 1 +0.006 -0.006 +0.114 -0.035 -0.129

    LESEN: 2 +0.082 -0.078 -0.267 -0.095 -0.020

    LESEN: 3 -0.039 +0.044 +0.013 -0.092 -0.197

    LESEN: 4 +0.039 -0.223 -0.194 -0.063 -0.086

  • Samuel PinchesSamuel Pinches Posts: 2,841Administrator
    edited December 2018
    Welcome @Der_Muck !

    I did not have good results with the IR probe. I think the pattern of the coating on the bed confuses the probe.

    I suggest this: put a flat solid (no pattern) sheet on top of the bed, and try again.
    Post edited by Samuel Pinches on
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    edited December 2018
    Hi Samuel,
    I was testing it till 03:00 and it is how you write.
    When you go to the trigger high and go in X or Y the probe triggers sometimes because of the gridy surface.

    Guys dont go and buy the mini IR Probe for autobed leveling on the black strandard plate, its useless!

    @Samuel Pinches a microswitch would be the best but I realy dont know how to set the switch up and down or turn away while printing without loosing accuracy.   Next would be the BLtouch. How do you think about it? It would be the easyest way before I experiment with micro switches.
    My goal is to measure as exact as passible but is that realistic with such a probe? It must be min. +- 0,05mm accurate otherwise its generally better to do manual bed leveling or standard 5 point leveling, there you can reach easy the +- 0,05mm accuracy. That accuracy would be my max. limit I would like to work.

    Greets
    Post edited by Der_Muck on
  • Samuel PinchesSamuel Pinches Posts: 2,841Administrator
    edited December 2018
    Hi Chris,

    I'm sorry, I understand it is frustrating. I tried two different IR sensors, many hours too... I share your pain.

    I think Genuine BLtouch is the next best option. I have retreated to manual mesh bed levelling, because I don't have time to try the BLtouch at the moment.

    Best regards,
    Sam
    Post edited by Samuel Pinches on
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    Hi Samuel,
    nah it was no problem. Now I know much more about the system and how it works, I am new in such stuff, just got my A5 3 Weeks ago :dizzy:

    I followed your tip and add adress stickers on my beds meassurement positions and also on the Z home position.
    It worked this time but it was the same. Some stickers where not so correct and the probe measured near to the edge of the sticker what made the measurement wrong.   
    But in the end it worked and I have a mash saved.

    Can you tell me why the G29 A or the G29 Q doesnt work?   Wanted to do a auto bed leveling first and correct it manualy but it turned out thats not passible because G29 always starts the automatic mode and it ignores the A or Q or anything after the G29     http://marlinfw.org/docs/gcode/G029-abl.html

    So now I have the mash saved in the eeprom. Does it load the mash after a restart and the first G28? Or do I have to add a code in a script?

    Greets
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    Here is the result of the paper auto leveling



    @Samuel Pinches
    I used G28; M420 S in Pronterface. Than i got to Z0 and went +-X and +- Y   left side is at 0,2mm but when I go right, it scratches at 3/4 on the way.    

    I think it will not work ever because autoleveling at the beginning doesnt work at all and building a saved mash is maybe ok but when you use your printer next time it turns out that the mash is wrong.    Even only with G28 Z homing its better and it doesnt scratch my plate.

    Sorry for my english :D 
  • Samuel PinchesSamuel Pinches Posts: 2,841Administrator
    edited December 2018
    You need "M420 S1" to enable mesh levelling in your start gcode script. This command needs to be after the G28 command, as the G28 command disables mesh bed levelling.

    If you do manual mesh bed levelling, it should work well.

    Please note, there are several different auto bed levelling methods, so it is important to read the correct documentation for the method you are using (automatic bed levelling vs unified bed levelling). Adding more confusion, I think there is some difference between firmware versions too...

    Post edited by Samuel Pinches on
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    Hi Samuel,
    yeah i did the M420 S to set the saved mash leveling.    I strongly think that the mash leveling is inverted.

    I reduced the mash points from 5 to 4 rows and add 10mm space on every side because of the bed clamps. When I did it, the mash leveling now begins at the left. Before it began on the right.  Is this a sign of a bug and equals in a invertation? 

    When you look at the last picture you see the middle is about Z0, on the right level point (seen from the front) its +0,140.
    When the nozzle is 0,2 and i go right to the 0-2 point, the distance reduces with normal 5 point level.
    Than i load the mash, same situation, I go right and the nozzle crashes. Means for me, the leveling goes it the wrong direction.

    But all in all, yes I now will go back to the manual bed leveling like you did and when I have time, I will check out the BLtouch.
    I work on a  fine plasma cutting system in my work. There i have such a probe, in the end, the accuracy will show if its worth it. For me, a mechanical probe makes more sense because its easyer to use and much less error prone. With a IR probe its passible that even fingerprints can result in a wrong measurement.
  • Samuel PinchesSamuel Pinches Posts: 2,841Administrator
    To be very clear, I mean "M420 S1", not "M420 S" as you have written. My mesh bed levelling always starts on the left.
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    Hi Samuel, yes ment M420 S1   but it was the same. Now I am working with manual mash bed leveling an everything is fine.
  • Charly3Charly3 Posts: 35🌟 Super Member 🌟
    Got IR Sensoring on two A5. Whilst with one it works perfect, on the other it levels left 0,1 mm lower than right - constantly.Will try a sensor switch with the next days, for firmware and all other settings are similar. IR Probing seems to be a really miracle thing on the A5 Bed.
  • Der_MuckDer_Muck Posts: 265🌟 Super Member 🌟
    Yes, its because sometimes it focus on the glas spots, sometimes in the high of the black diamond surface.
    I now got the BLtouch but I hate the plastic pin and to that, you have to add a flat plate on the pin about 3-4mm diameter because of the black diamond surface. It would be the same problem like the IR probe has. 

    Only a probe whats about 0.05mm accurate is worth to be used. For now the manual mash bed leveling is without any problem.    I try to get the BLtouch heat resistent and get the plate on the tip. Only than its for me usable.
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