Since 1970s, Sumitomo's CBN (cubic boron nitride) grades named SUMIBORON has pioneered the development of sintered CBN tools successfully used in the tool making industries. These tool materials can be epoch-making in a sense of broadening the cutting application range.

Characteristics are excellent wear and fracture resistance, high quality finished surfaces as well as high performance.

Production Process
In the production process of SUMIBORON powder / CBN powder is firstly synthesized under the ultra - high pressure, and secondly, the synthesized crystalline grains are sintered. To manufacture final products round discs of SUMIBORON material are cut into specific shapes and brazed on to tool bodies made of cemented carbide, and after that finished by grinding the edge. In another process the final product can be obtained only by cutting blanks and finishing them.

Application area
SUMIBORON can perform machining of hardened steel, high cast iron and exotic metals where previously only grinding was done.

BNC2010 / BNC2020 Coated SUMIBORON

Coated CBN Grades for Hardened Steel Machining

BNC2010: A grade for high-precision machining applicable for finishing requiring good surface roughness and dimensional accuracy. Provides further improved wear resistance thanks to a newly developed CBN substrate coated with a TiCN layer. Reduces flank wear and achieves excellent surface finish thanks to newly developed special stable multi-layered coating. 

BNC2020: A general-purpose grade applicable to general hardened steel machining. A newly developed tough CBN-substrate coated with a highly wear-resistant TiAlN layer. Achieves more stable machining and longer tool life by em- ploying a highly adhesive layer for high chipping resistance.


•  BNC2010 for high precision
•  BNC2020 for general purpose
•  Grades for high-efficiency machining & longer tool life
•  One-use insert break master with chipbreaker types:
   NFV for finishing, NLV for light cutting, NSV for carburised layer removal
   WG/WH wiper for high efficiency, good surface quality

Read more ...  Initiates file download

BSME / SEXC series

CBN small hole boring bar systems

The CBN boring systems BSME and SEXC were developed specifically for the machining of ultra small diameter holes in hardened steel. The entire boring bar series is equipped with internal cooling. In order to achieve high rigidity and accuracy, all boring bars are designed in carbide. For easy setup and handling, the use of a clamping sleeve, which can take all boring bar sizes by the unified shaft, is provided.

BSME: Series with brazed CBN cutting edge with minimum bore diameter from 2,5mm up to 5,0mm.
SEXC: Series with indexable CBN insert with minimum bore diameter from 4,0mm up to 6,0mm.

•  New ultra small boring bar with CBN cutting edge
•  Internal coolant
•  Easy setting & handling
•  High accuracy & high rigidity
•  One sleeve for different diameters

Read more ...  Initiates file download

BN1000 (High Speed Machining), BN2000 (General Purpose Machining)

New Uncoated CBN Grades SUMIBORON for Machining of Hardened Steel

A new uncoated type of SUMIBORON that has newly developed high-purity ceramic binder. Both fracture and wear resistance are combined to achieve a stable tool life in a wide variety of hardened steel machining.
Available in single corner and multi-corner type inserts.

BN1000: Superior high-speed machining grade with the highest wear resistance of any uncoated SUMIBORON. Delivers excellent tool life in continuous cutting to light-interrupted cutting. Improved hardness and heat resistance from the high purity TiCN ceramic binder.

BN2000: General purpose grade suitable for typical hardened steel machining applications. Provides stable tool life in everything from continuous cutting to light-to-medium interrupted cutting. Stable surface roughness by increasing sharpness. Significant improvements in the performance of both by employing a high purity ceramic binder.

Read more ...  Initiates file download

FMU Type

High speed finishing of grey cast iron

The FMU SUMIBORON BN finish mill for high speed machining (vc=1500m/min) provides excellent surface roughness (Rz = 3,2; Ra = 1,0) and delivers a safety structure for the centrifugal force under high speed cutting conditions. Run-out is less than 10µm. FMU type ensures an easy assembling method by using the setting gauge. Running cost is reduced because of economical insert. 



BN7000 uncoated SUMIBORON

Uncoated CBN grade for high-speed finishing of cast iron, powdered metals and difficult-to-machine materials

Medium-grain CBN sintered to a high density to achieve the maximum content percentage. Also delivers superior fracture resistance by increasing the binding strength between CBN particles. Provides stable, long tool life for high-speed finishing work with cast iron. powdered metals and difficult-to-machine materials.

•  Excellent for high-speed finishing of cast iron
•  High efficiency machining of powdered metals
•  Able to machine exotic metals

Read more ...  Initiates file download

BN7500 uncoated SUMIBORON

New Uncoated CBN Grade for High Precision and High Efficiency Machining of Powdered Metal

High density sintered material made of micro-grained CBN grains provide excellent sharpness and wear resistance for high quality surfaces in sintered alloy finishing.

Available with 3 different types of edge treatment for machining sintered alloys of any shape or hardness:

BN7500 Standard Type
BN7500 LF Type
: Has a sharper edge designed specifically for machining sintered alloys with minimal burr and improved machining precision.
BN7500 HS Type: Has a strengthened cutting edge for stable chipping resistance during interrupted cutting and finishing. 


Coated CBN grade for ductile cast iron machining

First coated CBN grade for ductile iron. Recommended for high-speed, high-precision machining of ductile iron. It also provides a long, stable tool life in machining high-strength ductile cast iron, special cast irons such as vermicular cast iron, and centrifugally cast iron. In addition, it demonstrates exceptional wear resistance by combining a ceramic coating with excellent heat resistance.