Today's CAD / CAM systems can precisely control the length of the knife in the high-speed cycloid tool path (note: the cycloid path is a curved path formed by a fixed point along a straight line) Very high cutting accuracy. Even when the cutter cut into the corner or other complex geometric shapes, the knife will not increase the amount of knife. In order to take full advantage of this technological advance, tool manufacturers have designed and developed advanced small diameter milling cutters. Small diameter milling cutters are less expensive than larger diameter mills, and more workpieces can often be removed per unit time by using high-speed tool paths. This is because the large diameter milling cutter and the workpiece contact surface is larger, so the need to reduce the feed rate, using a more traditional small feed rate. Therefore, the small diameter cutter can get higher metal removal rate.