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Zeroing is 0.5mm under surface when milling from fusion G-Code

Im trying to mill out a aluminium panel front using gcode from Fusion 360 with the contour mill with tabs. The first cut is supposed to be 0.5mm (which it does state in the gcode):

G90G94
G17
G21

(TOOL/MILL,1.65,0,8.6,0)
(STOCK/BLOCK,215,101.13,1.5,0, 0, 0)
M9
T1M6
S10000M3
G54
M8
G0X48.508Y47.99
Z15.5
Z4
G1Z1.5F100
Z-0.5F60
X47.749Y47.957F125
X46.998Y47.847

But when i import the gcode into the easel webpage and run it, the carvey machine runs the first cut 1mm deep. I did watch the machine inspector while it was running, and it claims the cut is at Z: -0.500mm, while it actually is at -1mm.

Without changing the work holding i ran a 0.5mm deep milling using a square i drew with the easel software, and it cut to the specified depth.

Do anyone know what i am doing wrong?

Thanks for any help

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I did do a test run of a 0.5mm deep square made with the easel software without changing the clampdown of the part, and it ran at the correct depth, so i would be surprised if the steps per mm is off. The cuts were made in very flat MDF, so it shouldnt be a surface problem either

The two cuts were crossing each other on the same plate, one measuring 1mm the other 0.5mm,

I did this three times in a row, on different plates. Every milling using imported gcode was 0.5mm too deep, while the easel code was at the correct depth.

The problem is in the zeroing being 0.5 mm off when i import the gcode, if i run a G0 Z1 after it has zeroed on easel code, the endmill stops 1 mm over the MDF, if i run a G0 Z1 after zeroing with the imported gcode, the endmill stops 0.5mm over the same spot

Try exporting the Easel G-code to see what it produces compared to the Fusion G-code.

When exporting the easel gcode i get this, it does seem to have quite a different “flavor” than the fusion gcode. I do use the F360-Easel.cps post config file for fusion, but it is strange they are so different!

G90
G21
G28
G21 G38.2 Z-71 F80
G10 L20 P1 X17 Y-12.25 Z12.7
G54
G0 Z20
G0 X20 Y20
M3 S12000
G0 X58.233 Y51.641
G1 Z-0.500 F228.6
G1 X38.305 Y51.641 F1219.2

Edit: I just tried to import the same code i exported, and i got a lot of invalid g-codes, so it seems that the exported g-code is not supported by easel for import…

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The Fusion G-code does not include probing, but the Easel G-code does. 0.5 mm is pretty small (about the thickness of a piece of paper) and would be an easy error to make in setting Work Zero manually.

Could that be your issue?

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Easel adds the probing before running the fusion gcode, so its the machine setting the z-zero height, and it does it consistently (but 0.5mm lower than the plate when running imported code).

I have tried to override the probing sequence setting, but easel dosent accept tool offset codes in imported gcodes…

There is a 1mm difference in the G-code.

Fusion G-code:

15.5 + 4 + 1.5 - 0.5 = 20.5

Easel exported G-code

20 - 0.5 = 19.5

What is your G28 position set to?

I’ve already demonstrated that what I know about g-code is distorted by coming from 3D printing and misinterpreting which bits of the log in Carbide Motion are coming from Grbl and which are translated, but I thought G90 was absolute mode.

@MarkWalker

By now I should know better than answering forum questions when I’m tired.

It is. Please disregard earlier post.

You have a G28 command in the G-code exported from Easel.

G28 tells the machine to move to a pre-defined location in machine co-ordinates that is stored in grbl’s space. If you haven’t set that position and the G-code doesn’t set it then that could be causing a problem. You can determine what is in the setting with a $# command to grbl.

Just to be sure, check your offsets in Fusion 360 when creating your tool path. I typically set a -.5 offset to finish cutting through the model and that might be your problem? I know it’s too simple a fix, like is it plugged in? I’m a real noob in both Fusion 360 and CNC in general so…

hello boys! it looks like i got the same issue as my bit plunges into my material with 1mm over…actualy im trying to cut a aluminuim sheet of 05mm countour with tabs but the bit goes way lower then the how material from the first cut, even if i have set multiple depths…excuse my english! kind regards!

(Just for people joining this later–a piece of paper is about a 0.1mm, 0.0039", unless it’s quite thick paper.)