3D Touch working ... but not totally

[Rege]

Hello,
I've an issue with my 3D touch on my I3 PROB acrylic:
installed its following the guide, no problem with hardware nor firmware.

Tuning of Z offset done.
G28 and G29 works fine , and I can see Z motors working during a layer, proof that the sense of the bed is taken in account in my marlin.
Video showing the init & good start of the print with 3Dtouch:
https://youtu.be/HVo79KxrjIE

The problem is that during print, the needle falls, and removes the layer already there (see video)
https://youtu.be/JCAzD4juWuI

So i tried to put in my start G code a command M280 P0 S90 (to pull the pin up) but it always falls after a while...

What is the issue , what can I do ?

[slipknot28]

I can not see on the video is pin down (because red light is on which means that pin is up).
If pin is not down I think only problem you have is that your sensor is too low.

Raise the sensor a bit and everything will be ok.

[Rege]

Hello - Thanks for your answer.

I tried to raise the Sensor (by changing the support), but the result is the same.
I have now a Z offset around 1.8, but when the print starts, after a while the needle fall, even if the sensor led is still active.
You may see it in my first video around 1min16s - https://youtu.be/HVo79KxrjIE

After this moment the light is ON but the needle is down.

I tried also to re calibrate the sensor magnetic force (with the upper hex screw) with no success...

[William]

Hi,I think the magnet of the probe are not strong enough to keep it up while working.
According to this

I tried also to re calibrate the sensor magnetic force (with the upper hex screw) with no success...

,it only adjust the position of probe and it cannot increase the magnetic force.
So I suggest you can change a probe which have stronger magnetic force to make it work again.

[andreb70]

Hi,

Dont now if this helps after that time. But i did see a vid to fix this!!

https://www.youtube.com/watch?v=eDfGZ4bjxiM

Magnatize the needle with a other magnat.

Seeya, Andre