Human societies have come a long way since the first metalworking lathe was invented just over 200 years ago, and our technology has progressed at an endlessly accelerating rate! Our modern technology requires sophisticated parts and tools, sometimes incredibly tiny or complex, that are created perfectly identically every time. This is where CNC comes in! CNC stands for computer numerical controlled, and refers to a huge range of machines that use computer logic to perform metalworking under precise control.

CNC works using the same metrics as a standard graph, with an X, Y, and Z axis denoting movements across the left-right, front-back, and up-down directions, which is combined with the ability to rotate and manoeuvre the material being worked on. Through this system, CNC machines can tool, drill, and cut metals, composites, or other materials into intricate parts with consistent perfection. CNC can be used with laser cutters, high-pressure jet cutters, milling machines, punch presses, and a host of other industrial tooling machines.

The quality of the machining produced, and the longevity of the tool bits used, comes down to the material used as the tip. Some of the main materials used for CNC tool bits are high-speed steel (HSS), and solid tungsten carbide.

HSS vs Carbide

High-speed steel is typically smelted down from raw ore, with additional minerals and additives included to boost its strength and structure. HSS replaced carbon-heavy steels popular during the mid-20th century, and offered higher durability and longevity.

Solid tungsten carbide end mills are crafted from particles of tungsten carbide fused together with the aid of metallic cobalt. Tungsten is the heavy metal with the highest melting point on the periodic table, due to it having the lowest coefficient of thermal expansion of any pure metal. Tungsten carbide, sometimes referred to simply as ‘hard metal’, can only be shaped, polished, or cut with the use of harder materials such as diamond. Solid carbide milling cutters exhibit better strength and durability than HSS, and maintain sharpness longer.