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products

CBN, PKD, CVD

our product range

E. Gräber diamond-tools are known because of their highly engineered geometries and innovative cutting materials. Best performance and tool-life is guaranteed. By using our solutions your production can be optimized and down-times reduced. This protects your machines and reduces the costs for maintenance work.
E. Gräber diamond-tools are produced under the highest production and quality demands. To achieve the best quality only the best materials are used for our tools. Our most modern measurement and testing technology and our quality-management guarantee you the safety to get the best possible planning and production reliability.

CBN

inserts

CBN is the hardest material after diamond:

Since diamond, known as the hardest material, cannot be used in ferrous machining applications because of the chemical reaction which turns the diamond into graphite, the developing of CBN and cuttings produced from it caused a bigger application range.

Similar to PCD the bonding between crystals effect a randomly oriented and homogeneous structure. This composition of a tough carbide layer and a brazed CBN cutting edge gives the CBN-insert the ability to resist high cutting speeds and cutting forces. This is the reason why CBN can also be used in heavy interrupted cutting applications.

The CBN-layer has also a much higher conductivity in comparison to carbide and ceramic, in turning and milling applications the heat is absorbed much faster. During the machining process of hardened, abrasive and tough materials high temperatures are created which cause a weakness or deformation of conventional cutting materials.

CBN keeps the toughness, tensile-strength and is chemical inert to metals like Iron, nickel and cobalt up to temperatures of 1000 degrees Celsius.

PKD

inserts

Initially, the production of highly efficient abrasives was at the center of interest. In 1972, polycrystalline diamond cutting could be produced by means of special bonding processes from the diamond microcrystals. About one year later this technique could also be extended to cubic boron nitride.
The diamond crystals of the polycrystalline cutting materials are non-directional. The hardness and abrasion resistance of the diamond layer are therefore uniform in all directions.
In contrast to the single-crystal natural diamond, there are no hard and soft or weakly bound planes, which can lead to a gross split. Therefore, it is also not necessary to give a preferred orientation to PCD inserts in order to optimize their performance during machining.
Whenever conventional cutting materials, such as carbide or ceramics, fail during machining or only achieve short cutting life, polycrystalline cutting materials are now available. Thanks to their much greater hardness, they can be used to achieve considerable improvements in all production parameters. In particular, very high cutting speeds with great machining accuracy and extremely long service lives offer enormous advantages.

CVD

inserts

In its wear resistance and service life, CVD diamond surpasses the cutting material PKD. CVD diamond also has higher thermal and chemical stability.
Basically, however, CVD diamond differs in the manufacturing process and in the construction of PKD. In a special CVD (chemical vapor deposition) process, smallest diamond crystals are deposited from the gas phase on a substrate and grow together to form a dense polymeric diamond substrate.
As a result of the missing matrix, the diamond content is higher than for PCD. However, this also results in a disadvantage compared to PCD – the fracture toughness is lower.
Wherever PCD reaches its limits in terms of wear resistance (high abrasive materials), we use the cutting material CVD.
Due to the more complex manufacturing process, the cost of a CVD diamond cutting tool is higher than a comparable PCD tool.