BLTouch sensor not very reliable

[onki]

Hi,

I upgraded my i3 Alu to a (Geeetech) BLTouch sensor system in February. All printouts have been nice since that time.
A few days ago suddenly the trouble started. Some parts did not stick to the plate anymore and print failed several times.

Yesterday I watched the display during the bed levelling that the sensor is giving home positions with a difference of 1mm plus when the bed levelling is working towards the end (and my satin glas plate is flat and well levelled). This was the reason for the poor results because the bed levelling was extremely overcorrectiin due to the bad measurements.
After I disabled the bed levelling procedure the printouts are OK.

Looking through the web I have seen some reports that the cloned BL Touch sensors only work for a limited time and then they start to cause problems.

What is your opinion on that?

Best regards
Onki

[William]

Hi, you can refer to this:https://github.com/KevinOConnor/klipper/issues/955
I hope this can help you.

[onki]

Hi William,

The sensor has worked for several weeks and now I am getting problems with the accuracy of the z-probe.

I will run the suggested GCode on the terminal to see the results but I am pretty sure that the sensor is giving different home signals over time which will corrupt the bed levelling correction.

Best regards
Onki

[onki]

Hi,

I checked the results from bed levelling and found a 1 Millimeter difference from one corner to the other.
When I manually checked the distance with a 50µm feeler gauge I could see that my bed was perfectly levelled.

This means the BL-Touch sensor is causing a good levelling to be extremly bad corrected.
Now I rolled back to micro switch Z-homing and disabled ABL in my start script.
Print out worked well for the first layers but I have a sudden shift in my parts. But this also happened with the BL Touch and might be caused by a mechanical reason.
Next step is to remove the BL Touch from the printer and put to the trash. Since the extruder is in original condition after that I will add a part cooling fan to the assembly.

Best regards
Onki

[William]

Thanks for your feedback, maybe you can take out the 3d touch probe and re-magnetize.