Home > Machining technology > Processing sapphire/ruby

smooth and sharp edge as characteristic of single crystal material

Property of Sapphire/Ruby

Composition Al2O3
Structure Hexagonal crystal
Mechanical property Tensile strength: 0.5GPa
Bending strength:  0.5 to 0.7GPa
Compressive strength: 3.0 to 3.4GPa
Young’s modulus: 350 to 470GPa
Hardness: HK1,500 to 2,000
* Values for reference
  • High hardness and excellent wear and abrasion resistance.
  • Chemically stable with excellent chemical resistance and tolerance of a strong acid like hydrofluoric acid.
  • Excellent in heat resistance.
  • Excellent insulating property.
  • Excellent abrasion resistance property.
  • Excellent optical property.
  • Sapphire/ruby in the rough

    Sapphire/ruby in the rough

  • crystal structure of sapphire

    Crystal structure of sapphire

  • example of processing shape of sapphire/ruby

    Example of processing shape of sapphire/ruby

As Sapphire/ruby is a hard and bristle material, it is extremely difficult to process. To the contrary, it is able to shape a smooth and sharp edge, which is characteristic of single crystal materials.

Sapphire has such an excellent optical property as it becomes colorless and transparent when having polished, and is used as a material of observation and a sensor window.

Ruby has almost same physical property as sapphire, but it becomes red by getting mixed with chromium oxide. When you need to confirm visibility while using, ruby is more suitable than sapphire.

Processing sapphire/ruby

Processing sapphire/ruby


Polishing inner surface of hole
  • Ra0.0169

Processing sapphire

Polishing inner surface: Roughness of surface Ra0.0169.

Processing ruby


Perforation of ruby
  • In the center of concave R of cup shape, micro hole is processed.

Processing ruby

Perforation of ruby: Hole diameter φ42.2µm circularity 0.5µm

Examples of usage of sapphire/ruby

Machining technology