Just a wild guess, is static maybe contributing? Can you somehow ground work piece and try?
Are you trying to run dust collection, if so can you leave it turned off?
I have no Dust Collection At the Moment.
When i Ground the Aluminium does the Problem get even worst.
The Z Goes down even Faster.
Okay, this is above my understanding of electronics and interference and stuff, sorry. 
Couldn’t do that even in German. 
Wow. Not sure. I am going to tqke a back seat. Static made sense to me as you said it quits upon touching, but grounding should not have made it faster at all. Do you have any pictures of your set up?
Thx for your Help. I will make you pictures from everything.
It looks a bit rough at the moment because im ripping everything apart in Hope the find my Problem 
Hi Stefan,
I had Problems similar to your’s in the past, my z-axis was moving without g-code to move the z-axis.
This post from @jeffeb3 helped me to find the issue: Z-Axis moving up when in contact with material - #9 by jeffeb3 put a piece of paper on your leadscrew and make a video.
HTH
Cheers from Heidelberg and good luck with your problem solving attempts!
felix
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Hi,
i can check that.
But i can see my Cuppler turning when the z goes down.
At 0:44 you can see the step it makes.
The Black wire you see in the Video goes directly to PE.
In the video i touch the Aluminium and after that the Spindel Housing.
When i touch the Spindle, something happens and i dont know why.
I used the 4th Contact on Top of the Spindle to ground it.
I can Check with a multimeter between PE and the Spindle and i have contact.
Sorry for my Shaky Hands.
By doing a search I see we have a few people on here with a Tillboard. I am not so sure about that board. I cannot be of much help. You definitely have something odd going on there.
I think it is a communication issue. Somehow the ground wire is communicating to the board.
(Just my GUESS.) I think you need someone familiar with that board!
Do you have a router or something to try to see if it is the spindle causing the interference?
I also am not sure, but are all tools grounded in Germany?
Sady i have nothing else to test it with.
Normally everything should be grounded in germany with a metall case.
Its Strange that giving the spindle “More” PE does anything…
so I do I.t. for a living. One thing I can think of. The communication between pc and the board, is it away from anything it might get interference from?
The only things that are running when i do this tests are:
The Frequenz converter
My Laptop (tested it with another tablet and a 3. pc)
The Tillboard
The Waterpump
and the 24v power supply.
No. 
Only brown and blue cables as well. It does make sense to ground some things like a spindle though.
I cannot tell, but it looks like the aluminum is on aluminum or metal. Put the part you are machining on something that will insulate it. Rubber, wood, anything non conductive, and does it still do it?
Most of the mpcnc’s have wood as the base.
Sadly its a wood table.
And the Plate its on, is wood too.
Here a pictures of Everything.
I thougt of turn off the Waterpump to see if it maks a difference.
When i put the cable from the pump back in the wallet. The Spindle moves a bit.
I dont know what to do. It doesnt look that great at the moment. Its Just to test.
Some cable changed in testing and soldered back on.
After everything works, it gets in a nice enclosure where no dust or anything can come near it.
And no the chunks from testing are not the Problem. It was before
Are my cables not thick enough?
Should i buy new cables and build the clean enclosure before?
I can make a picture how everything is connect in photoshop. maybe i did somethin wrong?
I really need help, please
i will make u a picture now to hope to understand my setup Maybe u see instant whats wrong
Unfortunately, some of those spindles are terribly electrically noisy.
If grounding the workpiece makes it worse you have a big problem. I would start with testing things with a multimeter to see if you can track down stray voltages. From the ground pin to anything you can safely probe.
You need to clean up the board wiring, having wires cross over each other and all the components is not a good idea, and any wires related to the spindle need to be completely separate. They should not be bundled with other wires (ideally cross other wires at 90 degrees). Some spindles are really nasty. Getting shielded spindle wires and grounding the shielding at one end is also best practice.
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