Here is a milled aluminum buckle still attached to the blank it was machined from. If you look closely, you can see both striations and faceting on the surfaces from the cutter. The striations come from the “stepover”; the amount the ball nosed cutter is moved over for each successive traverse across the part. The faceting comes from approximating the curve of each traverse by moving the cutter in thousands of tiny straight line moves. Both of these parameters can be set during programming. A smoother less faceted surface comes at the expense of longer cutting time so a compromise is chosen depending on the needs of the customer. This part was cut with a 0.0938″ diameter ballcutter with a stepover of 0.005″ and approximates the curve within 0.001″. The cuts required 1/2 hour run time per side including picking out the corners with a smaller cutter.