Ultra-Precision Machining Technology of the Soft and Brittle Functional Crystal

As an important branch of materials, soft and brittle functional crystals (SBFC) are widely used in the field of modern technology. However, the softness, brittleness, deliquescence, and strongly anisotropic natures of these materials present a challenge for their ultra-precision machining. The definition of SBFC is firstly given and their applications in many fields are also presented. For the ultra-precision machining technologies to satisfy the applied requirements, many methods such as single diamond turning, ultra-precision grinding, magnetorheological Finishing and so on, are successfully applied in SBFC materials, the challenges and difficulties occurred during machining these SBFC materials, such as KH₂PO₄, CdZnTe and CaF₂, etc., are reviewed and the limits are also analyzed in detail. Moreover, many novel machining methods are suggested to achieve better surface quality and enhance machining efficiency.