NCB100 is a new tool material specifically developed by Sumitomo Electric Hardmetal (www.sumitomotool.com) for machining hard-to-cut high-specification materials; it is said to enable tool life to be dramatically increased (by up to 50 times) when compared with traditional carbide cutting inserts.

The new cutting inserts are the first to be produced from a totally new range of ultra-hard Binder-less Polycrystalline Cubic Boron Nitride (BL-PCBN) cutting materials using a new method of ‘direct conversion sintering’.

The material is “synthesised under static ultra-high pressure and elevated temperatures, using grains that are just a few tens of nano-metres in size, resulting in them being directly bonded to each other without the aid of any secondary phases or binder materials”.

Binders and the volumes of them used in producing cutting inserts can have a significant effect on their mechanical and thermal properties (and hence performance), which is why Sumitomo developed its Binder-less materials.

The hardness of the NCB100 insert far exceeds that of both single-crystal types and the more traditional sintered compacts; moreover, the new insert is also free from any influence of the ‘cleavage and anisotropy’ (strength variation when used in different directions) of single-crystal inserts.

Sumitomo says NCB100 has ultra-high levels of hardness, strength and thermal conductivity that surpass conventionally sintered PCBN compacts containing binder materials, adding that the enhanced physical properties of NCB100 give the cutting edge high levels of stability and wear-resistance — properties that are critical when machining difficult non-ferrous materials such as titanium alloys, cemented carbides, hard ceramics, Ni-based heat-resisting alloys and cobalt-chrome alloys used in medical applications.

In finish-turning trials against established carbide grades, NCB100 achieved significant levels of tool life improvement at cutting speeds up to 200m/min; it also proved to be highly stable when finish-turning Co-Cr alloys used in medical hip joints.

Moreover, the insert material can also be applied to high-speed milling applications, such as the finish-milling of titanium alloys and Ni-based heat-resisting alloys at speeds up to 700m/min.