Mitsubishi Carbide broadens CBN application range

Mitsubishi Carbide has introduced a general purpose Cubic boron nitride (CBN) insert grade, BC8020. It offers high speed continuous cutting operations in materials up to 60 HRC, as well as allowing greater depths of cut to be employed, such as when removing outer carburised layers on raw material.

General purpose is not a description usually associated with CBN. Traditionally CBN grades operate exceptionally well, but within the restrictions of a narrow band dictated strictly by the material being machined and very precise cutting parameters. Advancements in materials, coatings and manufacturing methods have combined together with increased knowledge of edge honing styles and chipbreakers to provide a new grade with a much wider application range. Mitsubishi's 'Particle Activated Sintering Method' creates a much stronger binding between the particles, enabling the main CBN material to have a more reliable and stronger cutting edge than previous grades. This added strength enables interrupted cutting without compromising tool life for high speed continuous operations on steels up to 60 HRC. In addition, high crater wear resistance makes it possible to use larger depths of cut than is usually possible for operations such as removing outer carburised layers on raw material. Another feature of the BC8020 series is the inclusion of chipbreakers for some insert styles. The chipbreaker geometry has a similar radius to the insert corner and optimises its position in relation to the cutting point to allow deeper cutting for increased metal removal rates. Wiper type inserts are included in the range for increased efficiency and improved surface finishes. To complete the choice for the cutting engineer and ensure the optimum insert can be chosen, BC8020 has three different edge honing styles FS for continuous cutting, GA for general cutting and TA for interrupted applications.