So I am running CNCjs, but have run UGS as well. Once on UGS, and now a few times on CNCjs, when my origin is not at at start point, it has to rapid transit to the first cut. It will drop 16mm (or similar depth) rapid, then begin operations at normal top height.

Not an issue with zero’ing at top height, and my retracts in Fusion360 are all around 2mm for clearance.

If I reload the Gcode, it’s fine. Kinda random. With plastics I can stop machine before endmill destruction. The CNCjs display actually shows -16mm on Z as it does this (I saw it once, other times I was not able to look at monitor). Then it goes to Z=0 and begins proper plunge.

Ideas as to what is happening?

*Update: I now manually set “Z8” in the place where you must delete the tool selection, and it goes to 8mm. Basically Fusion360 is not defining the first Z, so I feel that led to random instability. Why does fusion360 not make the first order some retract height, etc?!?*

**Photo:**

Origin is corner point of item, it transits fast thru PVC and then tries to start ‘proper’ pocket drilling at first hole. Today had a similar fail on the other axis too.

**Code below:**

%

(1001)

(T2 D=5.156 CR=0 - ZMIN=-10.451 - flat end mill)

G90

G17

G21

G28 G91 Z0

G90

(Drill1)

M9

T2 M6 ( <-- I always have to delete this tool selector line for grbl, no prob) *(Update now Z8 goes here)*

S20000 M3

G54

G0 X0 Y9.245

Z6

Z3

Z2

G1 Z-1.289 F100

G0 Z3

Z0.711

G1 Z-2.578 F100

G0 Z3

Z-0.578

G1 Z-3.867 F100

G0 Z3

Z-1.867

G1 Z-5.156 F100

G0 Z3

Z-3.156

G1 Z-6.445 F100

G0 Z3

Z-4.445

G1 Z-7.734 F100

G0 Z3

Z-5.734

G1 Z-9.023 F100

G0 Z3

Z-7.023

G1 Z-10.312 F100

G0 Z3

Z-8.312

G1 Z-10.451 F100

G0 Z3

Y-20.955

Z2

G1 Z-1.289 F100

G0 Z3

Z0.711

G1 Z-2.578 F100

G0 Z3

Z-0.578

G1 Z-3.867 F100

G0 Z3

Z-1.867

G1 Z-5.156 F100

G0 Z3

Z-3.156

G1 Z-6.445 F100

G0 Z3

Z-4.445

G1 Z-7.734 F100

G0 Z3

Z-5.734

G1 Z-9.023 F100

G0 Z3

Z-7.023

G1 Z-10.16 F100

G0 Z3

Z6

G28 G91 Z0

G90

G28 G91 X0 Y0

G90

M30

%