When optimizing milling performance, the number of cutting edges on the milling cutter is another critical factor. While having more than one cutting edge engaged in the cut at any given moment can be advantageous, too many engaged edges actually become a disadvantage. This is because not all cutting edges can simultaneously perform the cutting action during operation. Moreover, the power required for machining directly depends on how many cutting edges are actively involved in the process. From the perspective of chip formation, cutting edge load distribution, and overall machining results, the relative positioning of the milling cutter to the workpiece plays a crucial role. In face milling, using a cutter that’s roughly 30% wider than the intended cutting width—and positioning the cutter closer to the center of the workpiece—helps maintain relatively stable chip thickness throughout the process. Notably, the chip thickness tends to be slightly thinner during the entry and exit phases compared to when cutting at the center of the workpiece.

To ensure the use of a sufficiently high average chip thickness/feed per tooth, it is essential to correctly determine the appropriate number of milling cutter teeth for the specific operation. The pitch of the milling cutter refers to the distance between effective cutting edges. Based on this value, milling cutters can be classified into three types: fine-toothed cutters, coarse-toothed cutters, and extra-fine-toothed cutters.

Also related to the chip thickness in milling is the principal cutting edge angle of face mills. This angle is the one formed between the main cutting edge of the insert and the workpiece surface, and it typically comes in 45-degree, 90-degree variations, as well as with circular inserts. The direction of the cutting force changes significantly depending on the principal cutting edge angle: for a 90-degree angle, the primary force generated is radial, acting along the feed direction. This means the workpiece surface experiences minimal stress, making it particularly reliable when machining components with weaker structural integrity.

A milling cutter with a 45-degree main relief angle generates radial and axial cutting forces that are roughly equal, resulting in more balanced pressure distribution and reducing the power requirements for the machine tool. This makes it particularly well-suited for machining materials that produce short, brittle chips during milling.

A circular blade milling cutter features a continuously varying main cutting edge angle, ranging from 0 to 90 degrees—this variation primarily depends on the cutting depth. Such blades boast exceptionally strong cutting edges, and because the chips produced along the long cutting edge tend to be thin, they are well-suited for high feed rates. Additionally, the direction of the radial cutting force acting on the blade constantly shifts during operation, while the pressure generated throughout the machining process directly correlates with the cutting depth. Modern advancements in blade geometry and groove design have endowed circular cutters with advantages like smooth cutting performance, reduced demands on machine tool power, and enhanced stability. Today, these blades are no longer limited to being effective roughing tools—they’ve become widely used in both face milling and end milling applications.