3. Mechanical glass cutting

3.1 Principle

In the past, glass was cut using natural or synthetic diamonds. Today, we use a small-diameter cutting wheel made of very hard steel. These wheels are made of tungsten carbide and have a diameter of around 4.5 mm. They are mounted on the cutting head by means of a wheel holder.

When scribing with a tungsten carbide cutting wheel (with a V-shaped cutting edge), a small groove is formed on the surface of the glass under the influence of pressure, from which a crack propagates through the glass. This groove crosses the compression zone of the glass surface and, as the center is in tension, all that's needed is to break the sheet by pressing a sharp blow under the cut of the cutting wheel.