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.

1. TOP VIEW: The part has been milled, handworked and fine glass beaded. The logo was milled using 1/32″ diameter cutters and stands about 0.150″ tall. It is proud of the surface by about 0.025″

2. TOP VIEW #2: A view from the other end

3. UNDERSIDE VIEW: This side was milled first.

4. HALF MACHINED IN THE MILL: This part is being milled in my Haas Minimill. The underside is already finished and the first 2″ of the top is roughed. The red stuff peeking out at the corners is Plasticene used to dampen the vibration as the part is milled. The Plasticene and milling strategy of cutting it in 2″ sections was the only way to keep the part from self destructing during cutting. Blending of successive sections was done by dropping the cutter in small increments until the new cuts just kissed the previously milled surface.