G92 BUG in 5.2.x

[ataraxis 51]

Hi there!

 

We have installed an Buildtek Flexplate on our UM3 @work.

The problem with this setup is that automatic leveling does stop a bit too late so that the

first layer is pushed too hard into the bed.

 

Up to now we used the following startscript to increase the first layer height:

G91 ;Relative movement
G0 F15000 Z0.2  ; Move down the plate a bit
G92 Z0   ; Tell the printer that this is the zero position
G90 ;Disable relative movement

Unfortunately this doesn't work anymore since the last Update!

 

Why?

 

Thank you in advance,

ataraxis

Edited April 17, 2019 by ataraxis

[tinkergnome 926]

52 minutes ago, ataraxis said:

Why?

 

Because Firmware 5.2 does weird things if it processes a G92 command with Z parameter.

You should  report it back to your reseller to take sure that someone is taking note of it.

 

I don't know if it is a bug or intentional behavior, but you are not alone...

 

 

[ataraxis 51]

Absolutely... Thing is, that the build plate moves to somewhere in the middle of the build height if I add the above GCODE. So it is printing in the air @CarloK @SandervG

Edited April 17, 2019 by ataraxis

[ataraxis 51]

Any response from official side? 🙂 @CarloK @SandervG

Edited April 17, 2019 by ataraxis

[Smithy 1,141]

Have you turned off auto bed leveling on your UM3?

I have read some posts about that, that after upgrading the saved values from the auto leveling are wrong and therefore the printer prints in the air because the offset is set to some phantasie values.

[ataraxis 51]

nope, auto bed leveling is active on our printer - it levels before every print

Edited April 16, 2019 by ataraxis

[ataraxis 51]

This is how it looks like, btw: 

 

[polygonfuture 12]

I've noticed the inverse problem on my printer.  If autoleveling is not set to always, It tries to print at or below glass plate level, so it never extrudes and just scrapes on the glass.  Manual leveling doesnt fix the problem either.

 

Putting it back to always makes it work properly.   

 

[ataraxis 51]

Yeah, we saw both problems in fact, Yesterday I set it to weekly and it printed way too close - altough we leveled one Minute before.

[Trueblondegod 1]

Interesting.

The 5.2 thread issues never end.

 

Mine is slightly different to yours in the video.

mine goes to extrude the blob, Then the Bed drops for more extrusion. -Great. However when its finished...

the z goes UP to the print core, and forces the blob into the nozel then drags the blob across the plate, Being covered in plastic it then goes to start printing and every print is ruined.

 

Not going to be so eager to update my firmware in future thats for sure!