Simple understanding of industrial sapphire
- Industrial sapphire is corundum (Al2O3) — natural or synthetic — that does not reach decorative gem grade and is instead used for its hardness, temperature resistance and insulation.
- It serves two main purposes: substrate materials such as LED semiconductor substrates, and window materials for watch dials, aerospace and precision manufacturing.
- Its value comes from corundum’s property set: high temperature and corrosion resistance, high strength, Mohs 9 hardness, wear resistance, electrical insulation and hermeticity.
- The processing chain runs seed crystal, growth, orientation, boule, grinding and inspection, then slicing into wafers; the cutting steps decide consumable cost, cutting quality and downstream grinding allowance.
- Diamond wire loop cutting machines now outperform long-wire saws, lasers, band saws and waterjets on productivity, consumables and accuracy for sapphire slicing.
Simple understanding of industrial sapphire
In the gem world, all kinds of gem grade corundum other than ruby are called sapphires. The main component of sapphire is aluminum oxide (Al ∈ O;). Because it contains trace elements such as iron and titanium, it appears blue, sky blue, light blue and other colors.
Industrial sapphires generally refer to gemstones that cannot reach the level of decoration, take industrial diamonds as an example. The gear shafts in good mechanical watches are all made of diamonds,
However, this kind of diamond can only be used for tools, not for decoration. For example, glass knife, the diamond of the blade is also diamond. The truth is the same. Whether it is man-made or natural, and its level cannot reach the level of decoration, it is used for industrial purposes.
Industrial grade sapphire is mainly used for two purposes:
One is substrate materials, such as LED semiconductor substrate materials.The other is window materials, such as dial, aerospace, precision manufacturing, etc.
The large-sized flat sapphire used in the aerospace field, the large-sized high-quality sapphire, graphene, night vision infrared transmission equipment, satellite space technology and mobile phone screen in the semiconductor field, photoelectric field and military industry field also belong to. This is also due to the high temperature resistance, corrosion resistance, high strength, high hardness, good wear resistance, high insulation, good air tightness, good thermal insulation and other characteristics of corundum gemstones. This kind of gemstone is cheap for tens of dollars a piece. The better the quality, the higher the price. Similarly, the more high-tech fields need higher quality sapphires.
Processing technology of sapphire:
Seed crystal – long crystal – orientation – pulling out rod – rolling grinding – quality inspection to obtain mature crystal rod, as shown in the figure
Crystal
Crystal bar
After the crystal bar, the wafer is obtained through orientation, slicing, grinding, chamfering, polishing, cleaning and tasting. As shown below:
Wafer
The most important link in these processes is the crystal cutting into crystal bars and the cutting link of crystal bars into wafers. This link will affect the number of consumables, cutting quality, subsequent grinding thickness, etc.
At present, the mainstream of the market is the diamond long wire cutting machine, which can be divided into one-way cutting and two-way cutting, but the equipment is huge and expensive. Laser cutting has been gradually replaced.
In the past three years, diamond wire loop cutting machine has appeared again. Compared with long wire, laser, band saw and water jet cutter, it has improved a lot in terms of productivity, consumables and accuracy. As shown in the figure:
Frequently Asked Questions
What is industrial sapphire?
Industrial sapphire is gem-grade-reject or purpose-grown corundum (aluminum oxide) used for engineering rather than decoration. Trace elements such as iron and titanium give it blue tones, but its value in industry comes from hardness, temperature resistance and chemical stability, not appearance.
What is industrial sapphire used for?
Two main purposes: substrate materials, such as LED semiconductor substrates, and window materials, such as watch dials, aerospace windows and precision manufacturing viewports. Larger high-quality pieces serve semiconductor, optoelectronic, night-vision and satellite applications.
How is sapphire processed into wafers?
The chain runs: seed crystal, crystal growth, orientation, boule pulling, rolling and grinding, and quality inspection to produce a mature crystal bar. The bar is then oriented, sliced, ground, chamfered, polished and cleaned into wafers. The slicing steps are the most critical because they set consumable cost, cut quality and grinding allowance.
What machine is best for cutting sapphire?
Diamond wire loop cutting machines are the current best choice. Compared with long-wire saws, lasers, band saws and waterjets, they deliver better productivity, lower consumable cost and higher accuracy when slicing hard, brittle sapphire boules and wafers.
Reviewed by the Ensoll engineering team.
