The fourth tooth is out of the cut, so there is no force on that tooth. The third tooth is in the 180° position, and the chip thickness is back to 0, so there is no force on that tooth either. One tooth is in the 90° position (to the right), and forces are exerted, just like in Figure 2. One tooth is in the 0° position (top), so the chip thickness is 0 and the forces on that tooth are 0. Forces on a four-toothed tool rotating clockwise and slotting in the X direction, with only one tooth engaged.įigure 3 shows a four-toothed tool making a slot. However, if the tool has four teeth and is applied when slotting, something unusual happens-the forces on all the teeth sum to a constant.įigure 3.

The force will also vary for a three-toothed tool. It will start small, get large, then get small again, and the direction of the force will change as the tool rotates. It is easy to see that the force will not be constant for a two-toothed tool. The chip thickness is approximately h×sin(Φ), where Φ is the angular position of the tooth, measured from vertical. As the tooth rotates through the cut, the chip thickness starts at 0 when the tooth is vertical, reaches its maximum when the tooth is in the position shown and thins until the tooth exits the cut at the bottom. Figure 2 shows a two-toothed tool rotating clockwise, feeding to the right and creating a slot. When milling, the same formulas apply, but the direction of the force and the chip thickness both change as the tool rotates. Forces on a two-toothed tool rotating clockwise and slotting in the X direction.

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