boron carbide tool grinding effects arising from

 Tracing the Source of the polishing tool, do not know how many years of experience and development of precipitation, only know that in the long history of boron carbide tool grinding high hardness grinding consumables played an indelible role in all these high hardness materials include abrasive discs, abrasive powder. After a century granite core bits  of evolution, tool grinding process up gradually advanced and reasonable, the use of consumables is more and more, and constantly improve the physical form of supplies, making it more adapted to the tool itself, the higher hardness of this material, so that to improve grinding efficiency.
Machinery manufacturing, the tool cutting tool materials processing efficiency and quality, with a decisive role. Advanced computer integrated manufacturing systems appeared, a variety of difficult materials different industrial applications, high-speed cutting and high cutting precision machining, green manufacturing continue to move forward, especially on the tool cutting tool materials to a new higher requirements.
Since the 20th century, after a period of emerging applications of engineering materials difficult to machine metal and nonmetal materials. Original use tools, such as high-speed steel, carbide cutting tools, etc. could not do its processing requirements, in superhard cutting tool materials have come into being.
Only the first superhard diamond cubic boron nitride cutting tool materials (PCBN) two kinds. From the beginning of human use of natural diamond, and later successfully developed synthetic diamond cubic boron nitride, although these two materials have been widely used, but its price is high, forming are quite difficult, with diamond tool can not be processed ferrous metal , promote the application is limited.
New cutting tool material CNx calculated based on the bulk modulus, this compound can reach close to or even exceed the boron diamond hardness.
The use of de reactive magnetron sputtering process, scientific and technical personnel at home and abroad are different physical material base material film deposited on superhard CNx. This film has a high hardness, high wear resistance, low friction and strong thermal and other properties, and not a chemical reaction with the ferrous metals.
1.CNx mechanical properties of thin films
Domestic high-speed steel cutting tools carbide tools physicists deposited CNx films, the surface hardness was diamond cbn wheel  measured to be 4000? 7200HV. Visible CBN has reached its hardness hardness, but slightly lower than the synthetic diamond hardness. Some people have also been measured with the scratch method CNx film coating adhesion, verify its reach JB/T8365 standards.
2.CNx experimental coating tool
(1) CNx coated HSS tools drilling experiments
The author with a diameter Φ10.5mmM2 (W6Mo5Cr4V2) high-speed steel twist drill for CNx coating, coating thickness 3? 5μm. Before and after coating with the same drill 38CrNi3MoVA (after quenching, the hardness is 36? 40HRC) high strength steel drilling, hole depth of 12mm.
Cutting: feed rate f = 0.13mm / r, speed n = 600r/min, cutting speed v = 19.8m/min; without cutting fluid. Such conditions, drill a hole about consuming every 9.6s, tool wear value VB drill diameter measured at the flank face. Meanwhile, in order to carry out different coatings contrast, the author has made with conventional PVD TiN coating process M2 high speed steel twist drill, twist drill in conjunction with the drilling experiments.
As with 0.3mm flank wear was blunt criteria, CNx coated drills to drill 48 holes, about eight times the uncoated drill, TiN coated drills 2 times. Visible, CNx coating to improve wear resistance effect is very significant. TiN coated drill hole number 24. Uncoated M2 drill hole number 6.
(2) CNx coated carbide inserts turning experiments
① I use K30 carbide inserts as sds hammer drill bits  the substrate, coated CNx film, turning T12A hardened tool steel (hardness 61HRC). K30 it with uncoated blade comparison, contrast and cubic boron nitride participate (PCBN) tools.
Cutting: Cutting depth ap = 0.5mm, feed rate f = 0.1mm / r, cutting speed v = 60m/min. Tool geometry: rake angle γo = 0 °, clearance angle αo = 8 °, the main angle κr = 90 °, blade angle λS = -4 °, tip circular arc radius rε = 0.8mm.
Three kinds of knives (film) wear curves see. Visible, K30 uncoated carbide inserts turning hardened tool steel, only 3min, the flank wear VB, which amounts to 0.3mm. CNx coated blade when VB of 0.3mm, the cutting time up to 15min. The PCBN cutting tools 20min, VB side is 0.2mm. Expected life of more than PCBN turning 30min.