Thanks to all for the fast replies!
@David
If I understand correctly, I have to increase the idle current M906, not M916 (stand still current). I will try out this with the M906 in the config.

@Mrehorstdmd @DocTrucker
I will try this, if that with the M906 doesn't work.

Thanks again for your help.
Incidentally, I am Swiss and live with my wife in Malaysia. My English is not good so my wife does the translation. Because of the time difference, it may take a little longer for my answer.

here is an image of my 3D Printer. The wiring and finishing work aren't ready now.

@jens55
The M907 command put a strain on the motors, they all get warm, the NEMA 34 not much but the NEMA 23 on the X- and Y-axis gets hot, even though I specified only the Z motors with the M906 Z5600 I100 without Y and X.
I tend more and more to a Gear Reducer, but I have no clue which gearing I should take 10, 15, 20, 25, 30, 40, 50 or 100:1

@dc42
is it worth to repair the old board, which burnt through when the z-axis has fallen down
it's a shame about the Trinamic 5160

Board Picture 1
Board Picture 2

@dc42: yes, I will wait until the update arrives.

I will use two worm gear reductors, but I don't know actually which one I should take.
I read a lot in the internet about worm gear reductors and two of them are interessting.
The first is NMRV Worm Gear Reducer Nema 34 30:1 and the second is Rino Motorized Rotary Table Stang 30:1.

Here are the details of my motors
Datasheet Nema 34BK50-120.pdf
Datasheet Nema 34HS59-5004S.pdf

With the transmission ratio I am not sure that this is the right one. The Z-axis printerbed has a weight of about 45 kg and in additon the model you print

@mrehorstdmd
Is this possible with this motor

@Dougal1957
CCM Linear Rail

@jens55
The M907 command put a strain on the motors, they all get warm, the NEMA 34 not much but the NEMA 23 on the X- and Y-axis gets hot, even though I specified only the Z motors with the M906 Z5600 I100 without Y and X.
I tend more and more to a Gear Reducer, but I have no clue which gearing I should take 10, 15, 20, 25, 30, 40, 50 or 100:1

@dc42

Hello David
I typed on M906 Z5600 I100 and now the Z-axix holds 50kg after homing or Z-rides.
As soon as I put the order M917 Z100 the bed is falling down, also without weight on the Z-axis.
The Z-axis falls also down when I stop it or do a reset
In the attachment my config,g don't be scared, i am working on it how I have to adjust it. The RepRap firme ware is new for me.

config duet 3.txt

Marcel

Thanks to all for the fast replies!
@David
If I understand correctly, I have to increase the idle current M906, not M916 (stand still current). I will try out this with the M906 in the config.

@Mrehorstdmd @DocTrucker
I will try this, if that with the M906 doesn't work.

Thanks again for your help.
Incidentally, I am Swiss and live with my wife in Malaysia. My English is not good so my wife does the translation. Because of the time difference, it may take a little longer for my answer.

here is an image of my 3D Printer. The wiring and finishing work aren't ready now.

Hello
My name is Marcel. I try to build a 3D-Printer (cartesian printer) of my own. I am self-taught.
Here are the data of the printer:

• board: Duet3 Board
• Firmware: RepRap version 3
• Configuration tool: Version 2.1.3.
• Driving force: Y- and X-axis NEMA 23, Z-axis 2x NEMA 34 (34BK50-120) with magnet brake
• Extruder: Typhoon with NEMA 23
• process route: Y-axis 1100 mm
  X-axis 600 mm
  Z-axis 900 mm
• total weight: about 180 kg
  The printbed weights about 45 kg (a aluminium frame, a aluminium plate, a heating mat and a glas plate)
  So far everything works fine and the axis do what they should do. But as soon as I press the stop button (reset), the Z-axis falls down. This costs me the first Duet3 board (it's burned (destroyed)). I can prevent that with the magnetic brake by activating the brake beforehand. So far so good!!!
  The big issue is that as soon as the Z-axis stops after a movement, it drops down. Without the glas plate, it can hold the position but with the glas plate it doesn't work. It's clear to me that the glasplate is too heavy. I suspect it is the holding current.
  Now the questions:
• Can I increase the holding current?
• Can I set the holding current in the config?
• Can I keep the Z-axis-motors under constant current?
  I would be happy for help. If there is no solution for my problem, I will have to change the printer to a fixed printer plate,