G-coding problem

(Robert Mark Etherton Jr) #1

so I’ve been trying to convert this file I got and im so close but yet so far. im using free cad to convert it into g-code and there are certain codes that ig the shapeoko doesn’t understand and im confused on how to fix it and have it work. these codes are very confusing STARSSSS.nc (25.1 KB)

(Robert Mark Etherton Jr) #2

if someone could look at it and see whats happening :slight_smile:

(William Adams) #3

You seem to be using FreeCAD, presumably to process a DXF and to generate G-Code.

The CAM tool is supposed to be in metric:


But it then uses a G-Code to switch to Imperial:


(which is a bad practice)

The CAM tool seems to have been designed with 3D printing in mind:

(move nozzle to safe location for tool change)

You’re using non-standard tool numbering:

G28 Z0.0000 T208.0

(what is a #208 tool?)

And the G-Code is structured really oddly (what’s the point of the relative movement mode command before the tool change above?) and why would you put a command in-between the movement command and its coordinates?:

G90 X1.2937 Y10.6935 S5000.0000
G43 Z0.3127

We have a U.S. flag in SVG suited to importing and cutting at:

and the post after that has in already in a Carbide Create file.

The balance of that thread has information which you may find of assistance, and there should be a file of just the blue field.

(mikep) #4

The “convert” part CAM is called “post processing” or just “post” - that needs to be set up correctly for the machine that will do the work. There is really no such thing as “just gcode” that every machine can use. For example, what a 3d printer takes and what a mill takes may both be written in g-code, how they do so is different.

Providing the file you started with (whatever dxf or cad file), and what post you used would be very helpful.

Converting gcode by hand is generally not worth the effort.

(Neil Ferreri) #5

Looks to me like there is something wrong with the post processor. Your file says you used a linuxCnc post, but the gcode, as you know, is messed up.
Can you share the post processor file as well?

(William Adams) #6

Agree w/ @mikep and @neilferreri that the wrong post-processor is most likely the issue. See https://www.shapeoko.com/wiki/index.php/G-Code to learn about G-Codes.

(Robert Mark Etherton Jr) #7

yeah I got that stars file from my dad so idk ig its from a whole different type of cnc that they used :confused:
but thank you this is very helpful

(Robert Mark Etherton Jr) #8

cutting_board_Flag_of_the_United_States_canton.nc (1.8 MB)
^that is the original file I started with and the post I used was linuxCnc.

(William Adams) #9

A .nc file is an output format — it’s usually specific to a particular endmill (what size) and machine (what feed and speed) — it’s not something which one can readily use, save on an identical machine.

Please see: Creating designs from elements and work up toolpaths suitable to your endmills and machine.