Why should CNC end mill tools be passivated?

Do you know what is Passivation? It refers to the metal is oxidized by a strong oxidant or electrochemical method to make the surface become inactive or to transform the metal surface into a state that is not easy to be oxidized and delay the corrosion rate of the metal.

In fact, tool passivation is not what everyone understands literally, but a way to improve tool life. How the milling cutters improved and prolonged service life? It is by deburring, leveling and polishing!

Why is the tool passivation necessary?

The cutting edge of the tool sharpened by ordinary grinding wheel or diamond grinding wheel has microscopic gaps of different degrees (ie, tiny chipping and sawing). In the cutting process, the microscopic gap of the cutting edge of the tool is very easy to expand, which accelerates tool wear and damage.

Modern high-speed cutting and automated machine tools put forward higher requirements for tool performance and stability, especially coating tools must be passivated before coating to ensure the firmness and service life of the coating.

Passivation advantages are as follows:

1) Compared with the traditional physical sealing method, the passivation process has the characteristics of absolutely no increase in the thickness of the workpiece and no change in color, which improves the precision and added value of the end mill cutter and makes the operation more convenient;

2) Since the passivation process is carried out in a non-reactive state, the passivation agent can be added and used repeatedly, so the life is longer and the cost is more economical.

3) Passivation promotes the formation of the oxygen molecular structure passivation film on the metal surface, the film layer is dense, the performance is stable, and it has a self-repairing effect in the air, so compared with the traditional method of applying anti-rust oil, the passivation The passivation film is more stable and corrosion resistant.

The main passivation effect of carbide cutting tools is the rounding of the cutting edge: removing the burrs on the cutting edge and achieving precise and consistent rounding.

Cutting edge burrs cause tool wear, and the surface of the processed workpiece will become rough. After passivation treatment, the cutting edge becomes very smooth, which greatly reduces chipping and improves the surface finish of the workpiece.