How to judge the quality of end mills?

How to judge the quality of end mills?
1. Materials
The materials used in manufacturing end mills will significantly affect the performance of the cutting tools. High quality end mills are typically made of high-speed steel (HSS), solid hard alloy, or cobalt. High speed steel is affordable and an ideal choice for general processing applications. However, it is not suitable for cutting hard materials such as stainless steel. Solid hard alloy and cobalt end mills are more expensive, but they can handle high-speed machining and can cut hard materials.
2. Coating
It is crucial to protect the surface of the end mill from wear and prolong its service life. High quality end mills are equipped with coatings made of titanium nitride (TiN), carbon titanium nitride (TiCN), or aluminum titanium nitride (AlTiN). These coatings have higher lubrication, heat resistance, and corrosion resistance, making them an ideal choice for cutting hard materials.
3. Geometric shape
The geometric structure of end mills plays an important role in determining their performance. The angle, shape, and size of the end mill will affect the way it cuts different materials. High quality end mills have groove shapes optimized for specific types of materials and applications, achieving cleaner cutting, less chatter, and longer tool life.
4. Rigidity
The rigidity of the end mill determines its ability to handle high-speed machining and resist bending when cutting hard materials. High quality end mills are typically more robust due to their design and material composition, enabling them to handle more challenging machining operations with higher precision and efficiency.