Z_offset isn't respected

General Discussion
1

Basic Information:

Printer Model: Ender 3 Pro
MCU / Printerboard: MKS Robin E3
klippy(15).log (383.1 KB)

I did the bed leveling (bltouch) and the paper test with the resulting z_offest equal to 0.9. After that, I start printing and hotend scratches the bed. This is very strange if a z_offset is correct, so I performed another test changing the z_offest to 2.4 to check if something might change. The result is the same, hotend still scratches the bed.

The klippy.log shows the correct z_offset value (first 0.9 and 2.4 after manual change) and I don’t know what’s wrong. It looks like at the beginning of printing, the hotend is not adjusted to z_offset and bed leveling values.

2

You increased the offset, so it will try to go even lower. 2.4 means it moves another 2.4mm down after the sensor triggered.

Also make sure the z_offset isn’t also set in the grayed out area at the bottom of the file. That one will take priority over the one in the main config above.

3

So, why the 0.9 (result from the paper test) doesn’t work?

If I change it to 0, the hotend starts printing around 1-2 mm over the bed which is incorrect.

If I set it to 0.1, the hotend scratches the bed.

For me, it looks like any value (other than 0) doesn’t work at all.

I have a Creality BLTouch, and it’s mounted with an 8mm height difference as described in the instructions.

I’m so confused about it.

4

This seems odd. A genuine BLTouch has the following parameters that should be closely followed or otherwise it will deliver crappy results:

BLTouch_position

5

In my instructions, the mentioned 8mm is measured from a plastic corpus to the end of the hotend so this picture is pretty similar. If you add a 4 mm probe height to 4.3 mm it’s around 8 mm.

6

Do you have a link?

7

It was a paper one, I don’t have it anymore. But the dimensions are the same as on the above picture

8

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.