There are two main milling methods for carbide milling cutters relative to the feed direction of the workpiece and the rotation direction of the milling cutter:

The first is down milling, in which the rotation direction of the milling cutter is the same as the feed direction of the cutting. When the cutting starts, the milling cutter bites the workpiece and cuts off the last chip.

The second is reverse milling, in which the rotation direction of the milling cutter is opposite to the feed direction of the cutting. The milling cutter must slide on the workpiece for a period before starting to cut, starting with a cutting thickness of zero and reaching the maximum cutting thickness at the end of the cutting.

In down milling, the cutting force presses the workpiece against the worktable, and in reverse milling, the cutting force causes the workpiece to leave the worktable. Since down milling has the best cutting effect, down milling is usually the first choice. Reverse milling is only considered when there is a thread clearance problem on the machine tool or there is a problem that down milling cannot solve.

Every time the carbide milling cutter blade enters the cutting, the cutting edge is subjected to an impact load, the load size of which depends on the cross section of the chip, the workpiece material and the cutting type. Ideally, the milling cutter diameter should be larger than the workpiece width, and the milling cutter axis should always be slightly away from the workpiece centerline. When the tool is placed directly opposite the cutting center, burrs are easily generated. The direction of the radial cutting force will change constantly when the cutting edge enters and exits the cutting, the machine tool spindle may vibrate and be damaged, the blade may break and the machined surface will be very rough. If the carbide milling cutter is slightly off center, the direction of the cutting force will no longer fluctuate and the milling cutter will obtain a preload.