Some Information about End Mills (Rotational Cutters) for CNC Machines

Let's talk about the various types of end mills. There are up-cut, down-cut, compression cut end mills with varying numbers of flutes. End mills and bits have shanks with varying diameters and cutters of varying diameters also. Materials also vary with end mills and for appropriate applications. Finally, the shape of end mills vary depending on the application. What can you do with an end mill? Well, primarily, end mills are intended to cut horizontally. That's the beauty of end mills. They can also plunge (drill) into the material, but this is actually hard on end mills, unless the end mill has this feature. You will probably see many CNC machines ramping down as it cuts a horizontal edge to prevent excessive wear on the end mill. Up-cut, down-cut and compression cut determine the way the chips (cut material) are ejected and the smoothness of the surface. With an up-cut end mill, the chips will be ejected upward and the bottom of the material will be smooth. The down-cut end mill is the reverse by pushing the chips downward and the top of the material is smooth. You can guess what the compression end mill does... It creates a smooth surface on top and bottom, which is perfect for pre-laminated woods.