UM3E Auto bed leveling issue

[V3DPrinting 11]

Hi

 

I have an issue performing the auto bed leveling :

- the slot 2 nozzle height measurement procedure starts, but complete before the nozzle touches the glass plate : there is a gap of 3 mm approx

- then  the slot 1 nozzle height measurement procedure starts, but complete before the nozzle touches the glass plate : there is a gap of 3 mm approx

 

Done the auto bed leveling  3 or 4 times in a row, without completing the bed leveling procedure

Sometimes one nozzles touches the glass plate, but not the other.

Sometime the nozzles height measurement procedures completes, but the bed leveling procedure fails.

 

I've checked the bed sensor performance and the test was OK.

 

So I've done a manual leveling and disabled the auto bed leveling. But as I change often print cores, I would like to get back to the auto bed leveling enabled.

 

Thanks for your help.

[Crystalvalen 3]

I just did a bit of work this past week to fix a UM3 that was having similar issues. My first recommendation is almost always to start with a manual bed leveling, but it sounds like you've done that already. Kudos to you! 

 

In any of your tests, does the plate press the nozzles into the print head at all (as opposed to just lightly touching them)? If so, it may be a faulty connection with the sensor wires in the print head. There are two wires behind the print cores (red and white) which connect to a capacitative sensor board via contact springs to sense when the nozzle touches the plate. Especially on older or more frequently used machines, these wires can be knocked loose and may have to be reinserted. Here is a photo of the wires as they looked when they were disconnected on our printer:

 

[V3DPrinting 11]

Hi @Crystalvalen

 

I am aware of the connectors issue. I had to repair them on my two UM3E.

 

In fact the sensor is working. A bit too well because it get somehow saturated before the nozzle touches the build plate and detects that the capacitive charge has reached a plateau -> for the printer it has triggered the right height.

But it's in the air .....

 

I have a doubt about the glass plate accumulating too much charge with the 3D Lac coating. I don't clean my glass plates that often and when printing PETG or Nylon I can have a thicker coat.

[Crystalvalen 3]

Interesting indeed. Even if there is a higher charge, 3mm seems like an awfully far distance for the sensor to trigger. I'm afraid I haven't encountered that particular issue you are describing before (nor do I use 3D Lac), so I don't know anything for sure. I imagine nothing has changed recently in your working area which has its own electric field that may interfere?

 

If I do hear anything, I will be sure to let you know. In the meantime, if you find that wiping down the plate works or you come across any other solution, please do give us an update! I am sure it would be helpful to others reading in the future.

[V3DPrinting 11]

1 minute ago, Crystalvalen said:

 I imagine nothing has changed recently in your working area which has its own electric field that may interfere?

 

No still the same for a year now.

 

2 minutes ago, Crystalvalen said:

If I do hear anything, I will be sure to let you know. In the meantime, if you find that wiping down the plate works or you come across any other solution, please do give us an update! I am sure it would be helpful to others reading in the future.

 

Thanks ! If I have some more informations or a solution, I will post it.

 

BTW my other UM3E doesn't have that issue though I don't care much of the glass plates.