Trying to understand GCode Post 1.6

Just assembling my table and working on a simple test card in fusion to start figuring out the machine. I’m looking at the GCode generated out of fusion. I’m very familiar with GCode for milling. I’ve searched and found good explanations for the code here on the forum, but when I go through it in my head it seems the torch starts to cut at .6" over the top of the metal unless I’m not understanding the G38.4 probe retract (don’t use that on my mill). Here’s my thinking:

G0 X0.3195 Y2.1699. Starting position x,y. Torch is at some random height.
G92 Z0. Torch height is set to 0. So random height is z0.
G38.2 Z-5. F100. Probe down to top of metal and set z=0
G38.4 Z0.5 F20. Probe up to z=.5. Torch height is .5.
G92 Z0. Set torch height to 0. z0 is at .5 over metal
G0 Z0.04 (IHS Springback + Backlash) **Torch moves up .04. Torch height is .54"-backlash"
G92 Z0. **Set new height to z0. Torch height is about .54"
G0 Z0.15 (Pierce Height). Move to z=.15. Torch height is now about .69"
M3. Spindle speed/ignite torch
G4 P0.5. Pause
G0 Z0.063 (Cut Height) z move to .063. .15-.063=.087. 69-.087=.603 New torch height.
H1 turn on THC
G1 X2.5695 F150. Here we cut the line… but the torch is at .603 height
G0 Z1.

You have these two lines wrong.

G38.2 Z-5 F100 **probes down(up to 5") until the IHS switch opens (it does not set zero at this point)
G38.4 Z0.5 F20 **probes upward(up to .5") until the IHS switch closes. The following command sets Z zero at that location.

The zero, at this point, should be the top of the metal. It doesn’t raise the the full .5", it only raises until the switch closes and the torch should still be in contact with the metal at that point. The .5" value is only there to throw an error if it raises past that point without closing the switch.


Thanks! I figured the error was in that area - it’s where the numbers went wonky. Those commands aren’t used on the mill. That makes total sense.

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