IR Trigger height suddenly changed a lot

  • I had a print running overnight, and it went to the noodle fail. After that event the trigger height of my ir probe went from Z1.66 to Z4.85.
    I see no physical damage to the probe, and while the plastic coating on the capacitor in between the IR bulbs and the IR sensor did get torn at one point, that happened months ago and has had no effect on performance.

    The probe triggers at values over 500, which is expected. Its like nothing is wrong, except that the trigger point suddenly moved. Any ideas?

  • What was the cause of the noodle fail? Did the print head come into contact with the print and maybe jostle it loose?

  • I have been looking for exactly that. I cant find anything wrong. The print had a layer shift, i could see a blob that hung up the nozzle enough that it was then airprinting the supports and it was all spagetti time after that. But that did not seem to make the nozzle, hotend, mount, or sensor loose. At the moment i have recalibrated to this new larger offset and I am going to see if a print works fine with it in this state. But it sure seems wacky.

  • 0_1551990907802_0307191426_HDR.jpg
    Here we are printing with a recalibrated z offset of Z4.956
    This is the same part, after i resliced it and double checked all my settings. Hopefully it works. Its a 9 hour print.

  • administrators

    Have any of the IR components at the bottom edge of the sensor board become contaminated with filament?

  • @dc42

    i never thought of that. what is a safe way to clean them? I dont think there is actually plastic stuck on there, but there was contact between the sensor and some heated up molten plastic. I could see how some kind of contamination would cause a difference in refraction on either emitter or receiver and make it trigger at wrong height

  • administrators

    You can clean them using a cotton bud moistened in isopropyl alcohol.


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