IR Z Probe weird problem



  • So, this ist how i mounted the IR Z-Probe:0_1563135126938_3.back.jpg
    The whole 3D printer "was" a Tronxy X5S with a bedsize of 330x330. The Probe is mounted on the back of the whole Hotend-Construction with an Offset of 0mm in the x-axis and 43mm in the y-axis. (I have checked the wiring about 10 times now and I am 100% sure, that everything is fine.) Now the problem(driving me crazy for the past 2 days): the probe ist crazy accurate when probing the same spot over and over again, in my case X150 and Y150. Absolutely no issues! BUT: when i try to home Z for example at X0 and Y280, there is always a distance of the nozzle to the bed which is about 0.2-0.3mm when Z is set to 0. I only have this issue when I probe with y-axis-values above 200.
    The same problem occurs when I try to execute the AutoBedCompensation:
    0_1563135800033_Mesh-Test.png
    The further I go into Y-direction, the greater the distance between nozzle and bed... I have absolutely no clue what to do and I would be very thankful for any information/help.


  • administrators

    @flipil said in IR Z Probe weird problem:

    The further I go into Y-direction, the greater the distance between nozzle and bed... I have absolutely no clue what to do and I would be very thankful for any information/help.

    If it's a continuous increase as the Y coordinate increases, then I suspect that the print head is tilting by an amount that depends on the Y coordinate, when the Y coordinate is greater than 200. Because the probe is offset from the nozzle, tilt in one direction will change the relative heights of the nozzle and the probe. This causes an apparent change in trigger height. To test this, drop the nozzle until it is just touching the bed, and use feeler gauges to measure the distance between the bed and the bottom edge of the IR sensor board. Then repeat this at different Y positions.



  • But when I home Z for example at X20 Y0(left corner in the front), the nozzle distance at Z0 is just perfect. After the homing process I tried to adjust the bed with the screws manually to eliminate the biggest irregularities between the nozzle and the bed. I would say that the max. distance(error) between nozzle and bed is somewhere 0.1-0.2 mm after my manual adjustment and that error can be seen IN THE MIDDLE of the bed, not the edges. And that is the funny(or not so funny thing): the nozzle is exactly where it should be at the edges. That shows me that there is a slight drop/bending going on in the middle of the bed and not at the edges. The edges seem to be perfectly plane.
    I then tried to home(after manual adjustment) the nozzle at X150 Y280 and there was again an error with a value of aprox. 0.2-0.3mm.
    I am going to try to home the z axis with another bed material. Maybe that will solve the problem. I will report if my test was successful.
    But thank you for the quick answer. Great service here in the forum!!

    (I love the Duet2Wifi Board ^^)



  • Okey I got it: its the material of the bed! I dont know why and I dont really care. I took a piece of a 400x400 mm woodplate and started the whole AutobedCompensation process. Now Z0 is truely Z0 everywhere. Crazy accurate. I also moved the probe closer to the nozzle. Now the offset is only 15mm in the y-axis.
    Lessons learned: the probe is great(when you use the right bed material)


Log in to reply