Thread: Cnc

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So, I've been trying to teach myself CNC for the past few days. I have been fairly sucessful, but I have no real literature on the subject. Does anybody know of any good free resources for CNC. I am particularly interested in definitions of G codes and how and when to use them. I know G0-3 and G90,91, but that is it. We have a very small CNC lathe at my school and it would be quite useful if we could make tensile test specimens on it. Nobody here knows anything about CNC. Canned cycles like G71 and G72 are of particular interest to me.

Originally posted by 76GMC1500
So, I've been trying to teach myself CNC for the past few days. I have been fairly sucessful, but I have no real literature on the subject. Does anybody know of any good free resources for CNC. I am particularly interested in definitions of G codes and how and when to use them. I know G0-3 and G90,91, but that is it. We have a very small CNC lathe at my school and it would be quite useful if we could make tensile test specimens on it. Nobody here knows anything about CNC. Canned cycles like G71 and G72 are of particular interest to me.

Try a google search. Not quite sure what your after. My CNC software converts the job to G-code on it's own. The closest I get to the G-code is watching it scroll down the screen as the job is cutting.

Originally posted by techinspector1
HUH?

Let's see, the handles on the ends of the table moves it back and forth, the handle in the middle on the front moves it to you or away from you and the big crooked, long handle with the castellated interface moves the table up and down. Yeah, that's the way it works.

Is the castellated interface a fluid drive?

Originally posted by Streets
"G" as in "Gohnson Rod"???

www.cncci.com/resources/tips/ 15 gcode.htm

That's a forbidden area Streets, maybe it's because it has to do with "G" strings?

G codes and prepatpry codes which propt axis movement. M codes are misc codes which do little things such as switch tools in the tool magazine or carousel, or turn the spindle on/off. Then you need to specify modal or non-modal for each code. Modal means the code stays active until cancelled by another code, non-modal means code only applies to that exact opperation, and will be cancelled by the next line of code. This is important when you program rapid traverse and such so that you don't mistakenly rapid traverse while the cutter is in the workpiece.

There are online sources that list all of the codes for you. It sounds complicated, but it really isnt too bad once you get the hang of it. And also, once you master the G and M codes, try to move up to a CAD CAM system, where you simply draw the part in a CAD system in 3D solid model, the computer then automatically writes the code for you. This is the easiest way to do it, but it is still good to know the G and M codes so that you can over-ride any problems that may arise.