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G-Code, CAD, and CAM discussions / Probably a REALLY basic question....
« on: October 07, 2008, 10:28:11 PM »
Hi all:
I am in the process of converting a Super X3 mill to CNC. Still waiting on some pieces so I don't have anything to work with as of yet.
I've been reading the Mach3 docs, etc. but there is a very basic question that I am struggling to find an answer for. One of the first projects I expect to attempt after getting things going is to mill a steel tube (perhaps 12 in long, outer diameter 1.5", wall thickness about 0.125"). I'll be milling various slots and holes through the wall of the tube. At some point I expect to have an A axis with a rotary table so that I can rotate the tube but let's just assume I will mill the "top" of it (what's directly below the cutter) for now just for simplicity.
I've drawn the tube in a CAD program and am putting the cuts/holes in the model. My question is how does Mach3 or any other CNC program know what the shape is of the original material I am starting with. My intent is to buy a steel tube of the right dimensions but how do I tell the CNC program it is starting out with a tube of specified dimensions? I could just as easily put a solid block of metal there with squared edges and expect the cutter to whittle away all the excess material. Obviously not a good idea but the point is how does the program know what it is starting with? I must have to define this somewhere but I am clearly missing something.
Maybe a tube is too complex a case to use as an example with but even if I were going to cut a shape out of a rectangular block, don't I have to tell the program the starting dimensions of the block so it knows what has to be cut away?
Feel free to tell me I'm a dumb newb (I am!) but would be great to better understand how this works (or find out I am thinking about it the wrong way).
Thanks!!
XboxMeister
I am in the process of converting a Super X3 mill to CNC. Still waiting on some pieces so I don't have anything to work with as of yet.
I've been reading the Mach3 docs, etc. but there is a very basic question that I am struggling to find an answer for. One of the first projects I expect to attempt after getting things going is to mill a steel tube (perhaps 12 in long, outer diameter 1.5", wall thickness about 0.125"). I'll be milling various slots and holes through the wall of the tube. At some point I expect to have an A axis with a rotary table so that I can rotate the tube but let's just assume I will mill the "top" of it (what's directly below the cutter) for now just for simplicity.
I've drawn the tube in a CAD program and am putting the cuts/holes in the model. My question is how does Mach3 or any other CNC program know what the shape is of the original material I am starting with. My intent is to buy a steel tube of the right dimensions but how do I tell the CNC program it is starting out with a tube of specified dimensions? I could just as easily put a solid block of metal there with squared edges and expect the cutter to whittle away all the excess material. Obviously not a good idea but the point is how does the program know what it is starting with? I must have to define this somewhere but I am clearly missing something.
Maybe a tube is too complex a case to use as an example with but even if I were going to cut a shape out of a rectangular block, don't I have to tell the program the starting dimensions of the block so it knows what has to be cut away?
Feel free to tell me I'm a dumb newb (I am!) but would be great to better understand how this works (or find out I am thinking about it the wrong way).
Thanks!!
XboxMeister