[closed] FreeCAD path, strange movement in Z axis

andypugh wrote: Let's try to be clearer about this.

In your G-code you have:

Code:

G0 X-0.100 Y536.751 G0 Z4.000 G1 X-0.100 Y536.751 Z-0.100 F900.000 G1 X5.249 Y542.100 Z-0.100 F900.000

The third line is a move only in Z, as the machine is already at that XY point.
The fourth move is a G1 in X and Y at the same Z.

Exactly. That is what is supposed to happen.
But.... I ran the whole program. Alle movement commands except the Z movement in the G1 statements are executed.
The spindle does not move from the initial Z4 position, the X and Y movements are correct.

andypugh wrote: If the program runs to completion, finishing at X5.249 Y542.100 Z4.00 then the problem is _not_ spindle-at speed.

Ok, it does run the whole program at z=4. So I will stop pursuing the spindle-at-speed route

andypugh wrote: If the program pauses at X-0.100 Y536.751 Z4.000 and does not run to completion then spindle-at-speed seems like a very likely cause.

There is no pause, the program runs fine after toolchange and toolheight measurement.


The program does the initial xyz movements and they are correct. Until the first G1 command, of the G1 commands only the X and Y positions are executed. The Z value remains at 4.

It might be the speed, or at least thats the only thing left I guess. I will try again with different (slower) speed.

Does the DRO show 4.0 for the Z, or is it that the Z doesn't move when commanded?

andypugh wrote: Does the DRO show 4.0 for the Z, or is it that the Z doesn't move when commanded?

Was just about the post a video about the DRO.
There is something strange going on that might be my fault.
If you look at the DRO in the video you can see that right after the first G1 command the DRO goes to -0.1 But the spindle itself didn't move at all in the Z direction, it is physicaly still at 5 (in this case, I changed the gcode file a little).

I do not know how this is possible. My G54 and homing is correct to my knowledge (all the G0 commands work as they should).


Remove the .txt to watch this .mkv video

For now I blame the G43 that is inserted. Tomorrow I will know.

ikkuh wrote: If you look at the DRO in the video you can see that right after the first G1 command the DRO goes to -0.1 But the spindle itself didn't move at all in the Z direction, it is physicaly still at 5 (in this case, I changed the gcode file a little).

Right, this sounds like hardware / config.

It seem that the Z axis might be stalling. Try reducing the MAXACCEL value for Z. Initially by a lot, ie divide by 10. Just to see if that makes a difference.

andypugh wrote: Right, this sounds like hardware / config.

It seem that the Z axis might be stalling. Try reducing the MAXACCEL value for Z. Initially by a lot, ie divide by 10. Just to see if that makes a difference.

These are the values now. Not sure how low acceleration should go

Full .ini file at: git.cnckloon.nl/CNCZone/mesa_2019/raw/br...wZaxis/mesa_2019.ini