3D Touch Sensor:Auto-levelling for Geeetech 3D printer

[Richtofen]

NilasO -

After Reading through all this thread, it seems that you are the only one who got the 3D Touch (or BLTouch) sensor to work on an Acrylic I3 Pro B, and it has been using a different Marlin FW versión than the one suppplied by Geeetech.

New to 3D printing, I bought the I3 Pro B, assembled it (assembly instructions were not so bad, other than the poor layout); not without problems (here instructions suck) I managed to correct the wrong direction for the X axis (not new to Arduino), and get it printing, still with not so good quality, but good enough to print the support for the 3DTouch. I installed the sensor, modified the config.h and pins.h files as indicated in the wiki, and got the sensor to respond to the test commands, but I cannot complete calibration. If I calibrate the bed manually (with previous FW), and then follow the procedure as indicated, the extruder moves to all four corners, in each one the sensor comes out (not reaching the bed), retracts, and the extruder goes up a few mm before moving to the next corner.

Now I have read that the Z_PROBE_OFFSETs suggested would not allow it, and that the sensor Z min has polarity (vs the open/close of the Z normal endstop functioning), what could explain why the extruder goes up after the sensor fails to touch the bed. All this was to explain that I am almost there, but I have also read that you got it runing with the firmware you posted, and I am tempted to take this shortcut and use your solution.

Opening your config.h, it appears that you have a 2nd Z_MIN sensor (if what the comments say is meaningful). 1) Is that correct? 2) Can I just comment out those lines defining the Z_MIN_PROBE_PIN for the 2nd probe? 3) Having a 2nd Z_MIN sensor sounds good, as an additional limit control (and it is there after all), where is pin 30? in other words, how can I connect both the sensor and the original Z_MIN endstop? (if this is in fact what you have).

Thanks (to you and to all the other posters who helped me find out where I stand).

[flunk]

Having a 2nd Z_MIN sensor sounds good

I second that. Is that achievable? My 3DTouch is working fine after some initial struggles with the offset value, now I get good prints every time. I even tried the trick with a tilted bed. However, it would be nice with an additional safety end stop for Z-axis.

Greets from Sweden.

[jmt75]

Hi flunk

happy to read that some people reach to make this 3DTouch working. Mine is always blinking. When I tell it to push the pin, it just vibrate a little, and then it is in error because the pin stay inside, even if I turn the screw up or down. What is your secret to have it working? Can you help us to find THE solution, since I am afraid we cannot have it from Geeetech?

Thank you very much.

Greets from France

[flunk]

I actually, after my previous post, found out that my pin did not have a smooth surface and sometimes got stuck (blinking LED) . I removed the grub screw and the pin and then very, very carefully polished the pin.

Do not damage the heat shrink. Reassemble and it should work fine. Mine has been running a lot of prints since polishing, no problems at all.

[jmt75]

I actually, after my previous post, found out that my pin did not have a smooth surface and sometimes got stuck (blinking LED) . I removed the grub screw and the pin and then very, very carefully polished the pin.

Do not damage the heat shrink. Reassemble and it should work fine. Mine has been running a lot of prints since polishing, no problems at all.

Thank you for these details. So bad that we need ourselves to polish a pin... The finish of the product is... well... minimum.

For my sensor, I looked very close if the pin was sliding well, it is ok when there no electricity, but perhaps when the electro magnet is on, the pin is blocked by friction? I am tired to try to guess what happens. The product is not so cheap (near of 30€ delivers in France), and it doesn't work, that's all. I am trying to negociate a new one from Geeetech, and then I will decide if I buy a capacitive sensor, perhaps less accurate but a lot more reliable and cheaper.

[faridy100]

Hello !
I mounted the 3D sensor on my geeetech prusa i3 pro B and it works, but I have to calibrate the z offset for each print.
The offset can change to 0.4 mm and the first layer becomes bad.

Is it normal to have to calibrate the z offset before each printing?

Someone has an idea?

Thank you !

[NiklasO]

Not normal.
Do you have EEPROM enabled? If you have, do you save the offset to eeprom using M500 after change?
How do you set your offset?

[faridy100]

Yhank you for the answer

I followed the wiki instructions and the offset is saved well by the M500 command

[daveapplemotors]

Yes, I change the Z offset often. Sometimes from -1.95 all the way to -2.35. depending on temperature mostly. If the device has heated all day I use a larger offset--(higher absolute value. At least there is only one variable to change

I change it as needed. If it can't print because the nozzle is too close and I hear the extruder grinding then I go toward -1.95. If it is too loose or not sticking to the bed then I raise toward 2.35 usually about .05 at a time.

One real benefit of the ABL routine is watching the height of each corner and the center. I stop a print and make a small adjustment to a corner and then let the 3D touch measure again. It measures better than I do.

My glass bed top is still warped even though I bought double strength glass last week. It sags in the middle .2 to .3mm. I am going to get a thicker--hopefully flatter--aluminum plate and maybe tempered glass next.

[Porkisek]

Hello Everyone, greetings from Czech Republic. I am owner of geeetech prusa i3 pro B with 3d touch. I am tried firmware from NiklasO - firmware was flashed, when I tried level the bed there was strange movements on the right side:
20:05:40.759 : G29 Auto Bed Leveling
20:06:41.621 : Bilinear Leveling Grid:
20:06:41.621 : 0 1 2
20:06:41.621 : 0 -0.02 +0.13 +6.99
20:06:41.623 : 1 -0.06 +0.08 +8.98
20:06:41.623 : 2 +0.06 +0.21 +6.98
20:06:41.623 : X:196.00 Y:190.00 Z:4.54 E:0.00 Count X: 15680 Y:15200 Z:28672

Physically tip on sensor was not down, motor goes up at this points. Do you have some idea what is bad with my i3?? Thank you for your time and response....