Mach3 router skips in Z axis

[bulletje]

Please help me!!!!

After I zeroed my router to the work piece and start running the gcode the z axis starts moving to the z home switch.
When the z axis comes down it stops exactly 25mm above the workpiece and the dro shows zero.
It happens 9 out of 10 times.

Sometimes if it starts from the 0.0.0 position the z axis dro skips exactly 25 mm ant then starts counting normally.
When it returns to the workpeace it plunges 25mm down at full speed, it costs me plenty of broken endmills.

I cannot find the problem: I tested the connections of the wiring and all the hardware. and find there is no problem. Why this 25mm???

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• G-Code skips

[routalot]

Can you post a sample of Gcode for a program where this has happened and tell us what software you use?It might be that one of the parts has a Z0 at the base and one has it elsewhere.One other place to look for trouble is the coupling between the Z axis stepper and the leadscrew as it might have become a bit loose.

[bulletje]

It has nothing to do with the g-code because when I zero on the table and I referenced all home in Mach3 the z axis dro reading is 188.1234mm and the measurement is 188.1234 - 25 = 163.1234.
There are no loose screws or couplings I have checked them all on my very solid self build router. I used it for 3 years now without any problems. I use Fusion 360 and only mill aluminium very satisfying.

[awerby]

It sounds like you might have an erroneous offset programmed into your homing routine. Or it could be that your "safe Z" setting is 25mm lower than it should be.