Z axis is cutting below what gcode shows

I cut this hollow heart shape out and had to stop the machine just before ending.
The Z axis when I stopped it measures at -0.920" and the maximum depth set in the gcode is 0.750"
I was trying to keep a skin section with tabs since my wood measures 0.780" thick
This was cutting the profile section.
Anybody see what is happening.
I set z zero to the top of the work.

T1
G17
G20
G90
G0Z0.8000
G0X0.0000Y0.0000
S16000M3
G0X0.0000Y0.2278Z0.2000
G1Z-0.1000F10.0
G1X0.1643Y0.3921F40.0
G2X-0.1643Y0.3921I-0.1644J1.7784
G1X0.0000Y0.2278
G1X0.0000Y0.0878
G1X0.4596Y0.5474
G2X-0.4595Y0.5473I-0.4597J1.6231
G1X0.0000Y0.0878
G1X0.0000Y-0.0522
G1X0.7332Y0.6810
G3X0.7346Y0.7318I-0.0261J0.0261

Cut out 3000 lines of code.
End of gcode

G1Z-0.7500F10.0
G1X0.4413Y-1.8568F40.0
G1X0.4055Y-1.8915
G1X0.3682Y-1.9255
G1X0.3302Y-1.9581
G1X0.2913Y-1.9894
G1X0.2518Y-2.0193
G1X0.2115Y-2.0479
G1X0.1706Y-2.0751
G1X0.1307Y-2.1000
G1X0.1290Y-2.1010
G2X-0.1322Y-2.0989I-0.1289J0.2144
G1X-0.1719Y-2.0741
G1X-0.2127Y-2.0470
G1X-0.2527Y-2.0186
G1X-0.2921Y-1.9888
G1X-0.3308Y-1.9576
G1X-0.3686Y-1.9251
G1X-0.4057Y-1.8913
G1X-0.4413Y-1.8568
G1X-0.9253Y-1.3727
G1Z-0.7250
G1X-1.1905Y-1.1076
G0Z0.2000
M5

  • How did you zero Z ? (probe or manual?)
  • did the first pass look like it cut at the correct depth (0.1")?
  • If you jog the Z in the air 1 inch, does it actually move 1 inch ?
  • any chance your endmill may have slipped in the collet ?
3 Likes

I manually set Z
First pass looked correct depth .1"
I moved the Z axis around and yes it tracks to a ruler.
Endmill and spindle are tight.

I may have found the problem, I moved the machine over the side of the work to check the Z axis.
The Z axis wouldn’t move with the jog commands.
So I turned the machine off and hit initialize, got an error message grbl cannot find z stop.
So I turned everything off with power and then everything seems to work again.

Now for another maybe related question.
My bitsetter home did this once before, it slammed into the x side of the table.
Did this again after resetting everything.
I manually jogged over the bitsetter and hit the button for use current location.
It should be some small negative x number, it moved to -8.5" I know that isn’t correct.
Somehow it seems like the machine is loosing track of location.

How much room does your Z have to retract when zeroed? (How far is it from the limit switch when at Z0?)

1 Like

It looks like about 1 1/2" or so from the top of my wood surface which is z zero.
Something is screwy with my machine, I sent off a picture to carbide 3d just now.
Everything home great on the machine, did a tool change and the x axis misses the bitsetter by at least .5".
Every so often it crashes into the x axis side when going for the bitsetter.
20210929_163559

Losing steps maybe? Check pulley is tight on stepper motor, and check wiring harness to see if there are intermittent connections.

1 Like