Duet3 not changing Z height on second layer

[eduard]

@rjenkinsgb Sure, I don't take personal
If there was a backlash, the motor shaft would move, but the bed would not. However, the motor shaft does not move at the second layer.
I measured the backlash and about 0.01mm (the bed moves on a ball screw)

[rjenkinsgb]

@eduard
That could still be mechanical stiffness, giving the same effect.

The same test would prove or disprove that.

[rjenkinsgb]

Have you posted your config.g file yet?

[eduard]

@rjenkinsgb When I built it, I measured the backlash using the method you wrote. I have measured it several times since then and get the same value. This is unlikely to be where the problem comes from. Mainly because the bed goes higher (endstop) to the first layer and then comes lower, 0.2mm.

[eduard]

@rjenkinsgb Yes, but you can find here again:

config (1).g
homez (1).g
homeall (1).g
bed.g

[rjenkinsgb]

@eduard
If you reference it, get the bed & extruder up to temperature and then command Z to 0.2mm, can you still get the 0.2mm gauge in the gap without excess force?
Just to rule out any thermal effects.

I'm guessing the 0.6mm Z offset in the tool definition is the difference between the Z home height and the tool nozzle height?

You also try adding M669 K0 at the top of the config, before any drive or motor stuff. It should not make any difference as the default is cartesian mode, but you never know!

Other than mine being corexy and having two z motors, your general setup is quite similar, which is why it's so puzzling..
I'm also having problems with Z, but only relating to probing accuracy and not layer movements.

[deckingman]

@eduard In addition to the other advice you have been given, there is one other thing you can do which is to observe the commanded Z position in the web interface when you run your print. Looking through your gcode, after homing the printer using G28, there is a G1 Z move to +15 prior to priming the extruder. Does DWC show the Z position as being +15 at this point? After that, there is a G0..... Z move to 0.2. Is DWC showing the Z position to be 0.2 at this point in the file? The next Z move that I can see is on line 448 which is another G0 .......Z 0.4. Does DWC show Z0.4 at this point? If it does then the hardware and firmware would appear to be working as intended and if the Z axis doesn't move, then it must be for mechanical reasons or some issue which prevents the Z motor from moving as commanded. If DWC still shows the Z position to be 0.2 after the G0.....Z0.4 command, then there is a firmware issue which might be related to using G0 rather than the more normal G1.

[eduard]

@deckingman Thanks, I'll try and give feedback.

[eduard]

@deckingman It is possible to print out the G code while printing like on CNC?

[eduard]

Thank you all for your quick and efficient help.
I found the error, it was here:
G10 P0 X0 Y0 Z0 ; set tool 0 axis offsets
It was Z0.6, after an earlier setup and I skipped over it several times. In my case, zero is a good solution.

Hi,
Eduard