Limits in Milling

​Folks that come from the 3D printing world seem frustrated by CNC machining, especially milling. They want to be able to take a 3D CAD model and machine it…automatically….with one button…like a 3D printer. Modern CAM software is amazing. You can take that part model, enter some tool and stock information and generate a geometrically ideal tool path. But, physics can play havoc with geometry. The tools, fixture, workpiece and the machine itself are not rigid bodies. They all move and vibrate and that creates limitations.

The top image shows the stability lobe diagram in red that displays the physical limits of the tool and toolholder in a machine. Below the red line you are stable, above the line instability and chatter. Also on that chart is the torque and power curve displaying the limits of the machine’s spindle in pink. In the pink you are overloading the spindle. The lower left image shows how we embed the torque and power information into our software and, on the right, how it appears on our Dashboard. If you tap-test and respect the limits shown on the tool’s Dashboard, your geometrically perfect part program will now be physically possible to produce the part (that's lot’s of p’s).