Superhard tool material comparison

22 March 2022


Superhard material refers to materials with particularly high hardness, which can be divided into natural and artificial.

The superhard materials introduced in this article include ND/MCD/CVD/PCD/CBN, etc.


ND(Natural diamond)

Natural diamond has excellent properties such as high hardness, wear resistance, low friction coefficient, and good thermal conductivity. It is an ideal material for cutting non-ferrous metals and non-metallic materials, but its output is low and expensive.

The emergence of synthetic diamond has weakened the increasing trend of the use of natural single crystal diamond tools in the field of precision machining. Several synthetic diamonds have gradually occupied the less demanding precision machining market with their good performance-price ratio and gradually mature technology.


MCD(Monocrystalline Diamond)

MCD is an artificial single crystal made by high temperature and high pressure method. It has high hardness, high wear resistance and high thermal conductivity comparable to diamond. The internal crystal structure enables perfectly sharp cutting edges without surface defects. Tools made from this material have the highest dimensional stability, excellent cutting edge quality, excellent thermal conductivity, but increased brittleness. Recommended for the finishing of non-ferrous and non-metallic materials that do not contain abrasive particles, inclusions or silicon.


Application of single crystal tool


CVD(ChemicalVapor Deposition Diamond)

CVD, which is made by the chemical vapor deposition method, is generally colorless and transparent crystals with almost no impurities. It has high thermal conductivity, low friction, and high wear resistance, and can make the processed object have a higher quality machined surface.

They can be made into straightening tool blanks, wire drawing blanks, laser windows, domes, thermal coatings, etc., and can also be used to process non-ferrous materials such as ceramics, high-silicon aluminum, abrasive composites, and graphite.


cvd single crystal


PCD(Polycrystalline Diamond)

PCD is a polycrystalline material made of diamond powder through cobalt and other metal binders under high temperature and high pressure, and then through cutting, welding, sharpening, and other processes to make PCD tools. Typically, the layer thickness of the PCD composite sheet is about 0.3 to 1.0 mm. It can be made into PCD inserts, PCD turning tools, PCD milling cutters, PCD reamers, PCD drills and other structural forms. As a tool material, it has good wear resistance, has insufficient chemical stability at high temperatures, and is easily soluble in iron.

Machining metals with superhard tools

The use of PCD tools is limited to non-ferrous metals such as high silicon aluminum alloys, metal matrix composites (MMC), and carbon fiber reinforced plastics (CFRP). It can also be used for finishing titanium, but only in combination with coolant.

It should be pointed out that the surface quality of the cutting edge and the machined workpiece of the PCD tool is not as good as that of the ND, its machinability is also poor, and the grinding ratio is small. It is difficult to machine any shape according to the geometry of the nose, and it is difficult to manufacture indexable PCD inserts with chip breakers and other products with complex geometries.


CBN(Cubic Boron Nitride)

  CBN, polycrystalline cubic boron nitride, is the second hardest material after diamond. The high strength and wear resistance of this material make it useful for work-hardening materials, difficult-to-machine materials, cast iron (especially high-strength cast iron), sintered powder materials, and more. Modern CBN alloys are ceramic composites with 40–65% CBN content. The ceramic binder increases the wear resistance of CBN, which is prone to chemical wear without it. CBN is particularly effective for the processing of iron group metals and their alloys, especially suitable for high-speed cutting and dry cutting, And realized the replacement of grinding by turning and milling, greatly improving the production efficiency.
PCBN inserts for thermal spraying


More SuperHard Products Co., Ltd. Focusing on the research and development and production of superhard materials, we are committed to providing customers with more advanced superhard material tools. Superhard material cutting tools will play a more powerful role in the market with diversified manufacturing materials, and will also bring real profits and competitiveness to related manufacturing enterprises.



---EDITOR: Cynthia Lee

---POST: Cynthia Lee

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