What is the key difference between climb milling and conventional milling?

The key distinction between climb milling and conventional milling lies in the direction of the cutter's rotation relative to the workpiece. In climb milling, the cutter rotates in the same direction as the movement of the workpiece. This means that when the cutter engages with the material, it starts cutting at the top, creating a shearing action that tends to pull the workpiece into the cutter. This mode of operation can lead to more efficient material removal and can reduce tool wear.

This characteristic of climb milling makes it particularly advantageous in certain situations, providing benefits like improved surface finish and greater cutter life, especially when cutting softer materials. The understanding of this rotation direction is fundamental for machinists, as it impacts both the cutting forces involved and the overall machining effectiveness.

While the other answers touch on aspects related to speed, surface finish, and material hardness, they do not define the core mechanical difference between the two milling techniques as accurately as the correct choice does.