Today, Huilisheng brings you an overview of the types and characteristics of diamond cutting blades:
Natural Diamond (ND) Blades: Natural diamond is the hardest known natural mineral and is primarily used to manufacture precision turning tools.
After fine grinding, the cutting edge radius of a natural diamond tool can reach 0.01-0.002 μm.
Even under 1500x magnification, the cutting edge of a Natural Single Crystal Diamond (SCD) tool remains smooth.
When turning aluminum pistons, SCD tools can achieve a surface roughness (Ra) of 4 μm, whereas under the same cutting conditions,
PCD tools result in a roughness (Ra) of 15-50 μm. Using SCD tools on precision lathes enables mirror-like surface finishes in precision and ultra-precision machining.
Polycrystalline Diamond (PCD) Blades:PCD is a polycrystalline material synthesized under high temperature and ultra-high pressure,
where diamond micro-powder is bonded together using metal binders like cobalt, also known as sintered diamond. PCD can be sintered into solid milling cutters.
The PCD grains are randomly oriented, making the material isotropic with uniform hardness. Its graphitization temperature is 550°C.
PCD tools exhibit high hardness, high thermal conductivity, low coefficient of thermal expansion, high elastic modulus, low friction coefficient, and an extremely sharp cutting edge.
Polycrystalline Diamond Compact (PDC) Tools:To enhance the toughness and weldability of PCD inserts,
they are often combined with a carbide substrate to form Polycrystalline Diamond Compact (PDC) inserts.
This involves sintering a layer of PCD, typically 0.5-1 mm thick, onto a cemented carbide base.
The bending strength of the PDC insert is comparable to that of carbide, while its hardness is close to that of PCD, making it a suitable substitute for solid PCD.
Chemical Vapor Deposition (CVD) Thick-Film Diamond (TDF) Brazed Tools:These tools are made by first laser-cutting a CVD diamond thick film,
brazing it onto a substrate (usually K-grade carbide) to form a blank. This blank is then polished, brazed onto a tool body,
and finally ground to the required shape and cutting edge. CVD thick-film diamond (with film thickness ≥30 μm) possesses high hardness,
excellent wear resistance, and a low friction coefficient, making it an ideal material for cutting tools used on non-ferrous and non-metallic materials.
Diamond-Coated Tools:Diamond-coated tools are created by directly depositing a 1-25 μm thick diamond film onto substrates like carbide (K-grade) or ceramics using the CVD method.
The coating is isotropic with no cleavage planes. The hardness of these coated tools reaches 9800-10000 HV.
They also have very high thermal conductivity—up to 2000 W/m·K at room temperature, compared to just 80-100 W/m·K for carbide tools.
A key, unparalleled advantage of the CVD method is its ability to coat diamond onto tools of virtually any complex geometry, which is not feasible with PCD.
