The wear process of cutting machine tools can be divided into three stages:

1. Initial wear stage

The initial wear process of the cutting tool of the cutting machine is fast and the time is short. A newly sharpened tool has prominent peaks on its surface. During the friction process with chips, the pressure is uneven, and the pressure at the peak is very high, causing the peaks to quickly wear out, making the pressure tend to be uniform and slowing down the wear rate.

2. Normal wear stage

The surface of the cutting tool of the cutting machine undergoes initial wear, and the peak point is ground flat. The surface pressure tends to be uniform, and the wear amount VB of the tool increases uniformly with time. The wear curve at this stage is basically linear, and its slope represents the wear intensity, which is an important indicator for comparing tool performance.

3. Rapid wear stage

After the normal wear stage, the cutting edge of the cutting tool of the load cutting machine has become dull, and the cutting force and cutting temperature have sharply increased. The cause of wear has undergone a qualitative change, with surface fatigue of the tool, decreased performance, and a sharp increase in wear VB. The tool will quickly fail.

Cutting machine tool dullness standard:

When the tool wears out to a certain extent, it cannot be used anymore. This wear limit is called the bluntness standard for cutting machine tools.

Cutting machine tool life:

The actual cutting time that a new tool (or a tool that has been re sharpened) takes from the beginning of use until it reaches the dullness standard is called the tool life of a cutting machine.