First G Code - Seems to cut down to min Z at the start

Troubleshooting
1

Just have been able to get my machine calibrated and generated my first test G code.

Was running this code with the router off to just validate everything is ok. However, It cuts down to maximum depth at the start of the cut, then back up, then cuts normally. Also does a similar action at the end of the cut. Not sure what is causing this. I exported the G code following a tutorial with Fusion 360. If another software is easier I am more than willing to switch.

It is an L shape block 2" x 2".

G Code
(Test L)
(T1 D=6.35 CR=0 - ZMIN=-9.62 - flat end mill)
G90 G94
G17
G21
(When using Fusion for Personal Use, the feedrate of rapid)
(moves is reduced to match the feedrate of cutting moves,)
(which can increase machining time. Unrestricted rapid moves)
(are available with a Fusion Subscription.)
G28 G91 Z0
G90

(2D Contour1)
T1
S5000 M3
G17 G90 G94
G54
G0 X28.575 Y0
Z6
G1 Z1 F750
Z-4.81 F250
G3 X25.4 Y3.175 I-3.175 J0 F750
G1 X3.175
Y25.4
G3 X0 Y28.575 I-3.175 J0
G1 X-25.4
G3 X-28.575 Y25.4 I0 J-3.175
G1 Y-25.4
G3 X-25.4 Y-28.575 I3.175 J0
G1 X25.4
G3 X28.575 Y-25.4 I0 J3.175
G1 Y0
Z-9.62 F250
G3 X25.4 Y3.175 I-3.175 J0 F750
G1 X15.642
Z-6.62
X3.175
Y6.985
Z-9.62 F250
Y25.4 F750
G3 X0 Y28.575 I-3.175 J0
G1 X-25.4
G3 X-28.575 Y25.4 I0 J-3.175
G1 Y24.108
Z-6.62
Y9.758
Z-9.62 F250
Y-25.4 F750
G3 X-25.4 Y-28.575 I3.175 J0
G1 X-7.175
Z-6.62
X7.175
Z-9.62 F250
X25.4 F750
G3 X28.575 Y-25.4 I0 J3.175
G1 Y0
Z0
Z6

G28 G91 Z0
G90
G28 G91 X0 Y0
G90
M5
M30

2

KrabzCAM software doesn’t seem to exhibit this issue so assuming it is a FUSION 360 setting I dont understand.

1 Like
3

Steven Marcus wrote:

Was running this code with the router off to just validate everything is ok.
However, It cuts down to maximum depth at the start of the cut, then back up,
then cuts normally. Also does a similar action at the end of the cut. Not sure
what is causing this. I exported the G code following a tutorial with Fusion
360. If another software is easier I am more than willing to switch.

did you remember to set Z=0 to the top of the workpiece before you started?

David Lang

4

Yeah. I re did it a few times always with the same behavior. The other software worked without issues.

My only other guess is a mm to inch conversion not happening correctly for the z axis causing it to bottom out on the bottom stops of the machine. Not sure though

5

try removing the comments (anything in parens like this) just to see if that
changes the behavior.

Fusion also offers a preview of the gcode in action, run that and see what
happens.

David Lang

6

Writing as the person who wrote GCodeClean, that is absolutely terrible GCode. And ignoring the messing about with G1 vs. G0 that fusion 360 does (which the comment warns you about) this is really bad GCode. I would definitely find something else to generate your GCode.

Explaining that bit of GCode above

It’s just so baaaaad. For example, travelling above the work surface you honestly only need about 0.5mm clearance, 1mm if you’re paranoid, so raising to 6mm then back down to 1mm is simply about wasting time)

I use ESTLCam to generate my GCode, and I definitely recommend it. It can work with many different file types as its source, so it’s a great ‘one-stop shop’ for doing the CAM work.

2 Likes
7

Appreciate the explanation of what’s happening and I’ll definitely try the software you recommend as well. Thanks.

1 Like