Sapphire glass, a material characterized by exceptional hardness and high optical transmittance, is increasingly used in applications such as smartphone displays, watch crystals, and precision optical instruments. However, its Mohs hardness of 9 poses significant challenges to conventional cutting processes during manufacturing. This article examines the physical properties of sapphire glass and reviews mainstream cutting techniques, providing readers with a comprehensive overview of the processing methods for this special material.

1. Physical properties and cutting difficulties

Sapphire glass is not a traditional glass, but an artificial crystal grown from high-purity aluminum oxide (Al₂O3) single crystals. The physical properties of sapphire present a processing paradox: the efficiency of the diamond cutter wheels used in conventional glass cutting is significantly decreased when working with sapphire material, the tool wear rate accelerates, and sapphire is prone to developing microcracks during the cutting process.

2. Contrastive analysis of mainstream cutting technologies

Currently, the mature sapphire processing technologies in the industry are primarily divided into three categories, each with its own advantages and disadvantages.

(1) Laser invisible cutting technology

A picosecond laser operating at a wavelength of 1064nm is utilized to generate a modified layer within the material by means of focusing the beam. Its core advantage lies in the non-contact processing that avoids mechanical stress, making it particularly suitable for the precise cutting of micro-components.

(2) Diamond multi-wire saw cutting

This process incorporates advanced semiconductor wafer handling technology, utilizing a precise diamond wire saw measuring 0.12 mm in diameter, operating in conjunction with a specialized silicon carbide grinding fluid to ensure optimal results. This technology offers a cost-performance advantage in the processing of large-sized sapphire substrates (such as 4-inch wafers), with the processing time for a single piece controllable within 30 minutes.

(3) Water-guided laser cutting

This method couples the laser beam with a high-pressure water column (50 μm diameter) to combine the high precision of the laser with the cooling effect of the water flow. It can reduce the heat-affected zone of the cutting to less than 3μm, making it suitable for scenarios with strict edge quality requirements, such as endoscopes. Nevertheless, achieving optimal processing efficiency with water-guided laser cutting can be difficult when scaled up to meet large production demands.

Currently, sapphire glass cutting technology is undergoing a paradigm shift—from traditional mechanical processing toward photoelectric composite methods. The integration of intelligent cutting systems is transforming conventional manufacturing approaches. By incorporating machine vision and artificial intelligence algorithms, these systems enable real-time monitoring of material conditions and automatic parameter adjustment to optimize processing outcomes.