Ultimaker s5 fails on bed leveling repeatedly

[scummings 0]

My s5 continuously fails to level the bed. The bed will raise until it experiences resistance of the nozzle intermittently. Sometimes it will fail on the 1st extruder 2 test, sometimes the 2nd extruder one test, and sometimes as it surveys the bed with extruder 1 nozzle.  I have greased and lubricated the guides and drive screw, Restarted, factory reset. Nothing seems to fix this issue. I can run a print 20 times without being able to complete a leveling, and then randomly it will work.

The bed never reaches the nozzle when it fails. It seems like it experiences enough resistance to make the printer think it has met the nozzle, although it is approximately 1/4" away.

 

I have a video of this but cannot seem to upload it

 

[gr5 2,071]

How old is this printer?  Your description of the problem was very helpful.  This is what I recommend you do.  Well first contact your reseller and let them know.

 

Then you need to go into the maintenance menu and somewhere there is a test to test your sensor (by the way they call it "active leveling").  After the test it will display a number.  That number shows the rms noise at the sensor.  Values 8 and below are considered a pass.  Values above 8 are a fail.

 

Note that this test must be done with the bed heat off.  Unfortunately that is not enforced.  The true active leveling turns this off.  I'm told the results can vary with bed temp (even if the bed is off).

 

Do that test a few times and then the most common fix by far is related to your 3rd fan in the print head which is in the center - in the door that flips open.  The best thing to do is to unplug that fan which is not trivial as you have to take the head apart.  But you really should just bite the bullet and do that.  If that then passes then you can ask for a new fan.

 

There are many many other things that can make the test fail.  Bad wires to the middle fan.  Bad wires to the sensor (visible when you open the test head door you can see two wires (typically one red and one white) going to the base of the open door.

 

Sometimes you have to replace the circuit board in the print head.

 

Another option is you can turn off active leveling and do manual leveling instead.  ONly recommended if you use a small portion of the bed (like divide in your mind into tic tac toe and if you only use one or two squares).  This can get you going until you get this problem fixed:

 

[gr5 2,071]

By the way the sensor has nothing to do with mechanical resistance.  There is an electric property called capacitance which changes depending on the distance between the flat plate in the print head and the flat plate on the test bed.  As the bed moves up to the nozzle that capacitance changes and this changes the frequency of an oscillator.  When the nozzle touches the bed the frequency stops changing because the distance stops changing.

 

But if there is a lot of electric noise (like from nearby equipment - like a tesla charging 10 feet away or a mini fridge under the printer or the front fan on the printer) the frequency changes erratically and you get problems.

[scummings 0]

Thank you I will try this out!

[Torgeir 228]

Hi there.

 

Just come to think about an issue with two of the "late" firmware versions for the 3S and 5S printer's, as a few people lately complained about the bed leveling.

 

See this:

 

Bed leveling reliability

Ultimaker S-line firmware versions 7.0.4 and 7.1.0 contained an error in the bed leveling code. This caused an increase in failed bed leveling attempts when starting a print, while the hardware was working perfectly fine. This 7.1.3 release fixes the issue and significantly improves bed leveling performance.

 

Here's the direct link:

https://support.makerbot.com/s/article/1667410781982

 

Just to be mentioned.

 

Thanks

Torgeir