Introduction to Types of Diamond Cutting Tools
Diamond cutting tools are widely used in precision machining of non-metallic hard and brittle materials such as graphite, high-wear materials, composites, high-silicon aluminum alloys, and tough non-ferrous metals. Diamond tools offer extremely high hardness and wear resistance, low friction coefficient, high elastic modulus, high thermal conductivity, low thermal expansion coefficient, and low affinity with non-ferrous metals.
Types of Diamond Cutting Tools
1. Natural Diamond Tools
Natural diamond has been used as cutting tool material for over a hundred years. Natural single-crystal diamond tools can be ground to an extremely sharp cutting edge with a radius as small as 0.002 μm, enabling ultra-thin cutting and producing exceptional workpiece precision and extremely low surface roughness. They are recognized as the ideal and irreplaceable tools for ultra-precision machining.
2. PCD (Polycrystalline Diamond) Tools
Natural diamond is expensive, so polycrystalline diamond (PCD) is widely used in cutting applications. PCD blanks are produced using high-temperature, high-pressure (HTHP) synthesis technology. Since their development in the early 1970s, PCD tools have replaced natural diamond tools in many applications.
PCD raw materials are abundant and cost only a fraction of natural diamond. While PCD tools cannot achieve the extremely sharp cutting edges of natural diamond, they are suitable for precision cutting of non-ferrous metals and non-metallic materials. Modern PCD inserts often include chip-breaking grooves for improved performance.
3. CVD Diamond Tools
Chemical Vapor Deposition (CVD) diamond technology emerged in the late 1970s to early 1980s. CVD diamond refers to diamond films synthesized on heterogeneous substrates (such as cemented carbide or ceramics) using chemical vapor deposition. CVD diamond has the same structure and properties as natural diamond, combining the advantages of both natural single-crystal diamond and PCD while overcoming some of their limitations.
Performance Characteristics
- Extreme hardness and wear resistance — Diamond is the hardest known natural material. Diamond tool life is 10–100x (or even hundreds of times) longer than carbide tools when machining hard materials.
- Very low friction coefficient — Lower friction with non-ferrous metals reduces cutting force and workpiece deformation.
- Extremely sharp cutting edges — Natural single-crystal diamond tools can achieve edge radii of 0.002–0.008 μm for ultra-thin cutting and ultra-precision machining.
- High thermal conductivity — Excellent heat dissipation keeps the cutting edge cool during machining.
- Low thermal expansion coefficient — Minimal dimensional change from cutting heat, critical for precision and ultra-precision machining.
Applications
1. Difficult-to-Machine Non-Ferrous Metals
When machining copper, zinc, aluminum, and their alloys, these materials tend to adhere to cutting tools. Diamond tools prevent metal-to-tool bonding due to their low friction coefficient and low affinity with non-ferrous metals. The high elastic modulus ensures minimal deformation during cutting, improving surface quality.
2. Difficult-to-Machine Non-Metallic Materials
Materials containing large amounts of hard particles — such as glass fiber reinforced plastics, silicon-filled materials, and carbon fiber/epoxy composites — cause severe tool wear. Diamond tools’ high hardness and wear resistance enable efficient machining of these challenging materials.
3. Ultra-Precision Machining
With the advancement of modern integrated circuit technology, machining demands ever-higher precision. Diamond tools’ low friction coefficient, low thermal expansion, and high thermal conductivity enable extremely thin chip formation with easy chip evacuation, minimal built-up edge formation, and low heat generation — all essential for ultra-precision surface quality.
SINO SEIKO（Sino Qtech Industries Co., Ltd.） offers a complete range of PCD and PCBN cutting tools for precision machining applications. Contact us for product recommendations and technical consultation.
