Here’s one I wrote earlier

One of the more interesting aspects of a decent program structure is that you can easily edit it to suit another purpose.

So if I gave you a program which had a nice clean, well-commented structure, not only would that be quite unlike me, but you could identify which part of the program did what, and modify it to suit yourself.

So here’s a program to mill a legend, as shown in the photo at the side. The legend is the word CNC.

It is designed to fit in the centre of a space of approximately 37mm x 37mm on a workpiece 6mm thick (although the thickness doesn’t matter in this case, because the cut is only 0.2mm deep).

Download the program to cut the logo,

for Mach3,  here.

for LinuxCNC, here.

(Note: these are zip files, so you will need to unzip them once you have downloaded them.)

Load it into your CNC program, and check that the toolpath shows you the lettering - or at least the path the CP will take to create the lettering. Then look at the code (using the editor). If you prefer, you can load the whole program into a text editor.

In particular, check the comments which tell you what the various parts of the program do.

Save a copy of the program using a different name, delete

the sections which machine the letter N, then save that version of the program.

Now load that version back into your CNC program and look at the toolpath. It should only show the path for the CP to create the letters C and C.

Note carefully, though, that this new version uses the same Work Origin as the original, so if you were intending to machine this path, you would still need to set the Work Origin as shown by the green dot on the drawing at the side.  Not too much of a hardship with this program, but something to be aware of if the path was more complex, larger, or the remaining part was further away from the position of the Work Origin.

Note, too, that the letters C and C do not close up to occupy the space created by removing the N. The co-ordinates of the letters are fixed in relation to the Work Origin.

If you want to see my modified versions, you can download them

for Mach3, here.

for LinuxCNC, here.