Polycrystalline cubic boron nitride (PCBN) cutting tools and Problems

cubic boron nitride particle size PCBN tool not only affect the quality of the cutting surface, and a binder for PCBN sintering sintering ability to play a certain role. Generally,

CBN particle size is smaller, PCBN cutting tool surface quality better impact resistance and resistance tool

Better wear resistance, therefore, the machining of hardened steels and high surface quality requirements (i.e. implementation of PCBN cutting tools "In car instead of

grinding") is, PCBN cutting tools used in the CBN particles should take a smaller value. On the other hand, since the sintered PCBN inserts through the "capillarity

"That penetrate into the various adhesive element between the CBN particles, if the CBN particles are too small, CBN particles will reduce the gap between, so that the

penetration of the elements reduce the amount of the binder, so CBN sintered particles and to be elected for a large number of comprehensive consideration of the above

two

Variety of factors, CBN sintered mixed granularity should be more choice, and according to the selected adhesive bonding capacity of the different determine the

different particle size range.
CBN grain content
 PCBN tool in the CBN grain content on PCBN tool hardness, thermal conductivity have a greater impact. CBN content is higher, the higher the hardness of the tool, the

better thermal conductivity. High content PCBN tools (CBN content is generally 80% to 90%) is mainly direct binding between CBN

, Having high hardness and high thermal conductivity. Such PCBN cutting tools for machining high hardness alloys and hard tissues contain high particle materials, such

as chilled cast iron, heat-resistant alloys.
Binder
CBN sintered adhesive required: ① CBN closer the physical and chemical properties as possible, so as not to weaken too much the sintered PCBN cutting tools; ② easy

to reach the melting point temperature or at this temperature has good plasticity; ③ with respect to sufficient chemical activity CBN

Resistance, with the hexagonal boron nitride (HBN) catalytic conversion to the CBN.
Currently, the adhesive used to be divided according to their physical and chemical properties of the binder metal (such as Ni, Co, Ti, Ti-Al, etc.) and a ceramic

binder (such as TiN, TiC, TiCN, Al2O3, etc.); by function can be divided into a catalyst (such as Al, AlN, AlB2, Si, etc.) and solvent

Solution agents (such as Ti, Ni, Co, TiN, TiC, TiCN, etc.). Binder type and content of the performance of PCBN inserts are all have different effects. Carbides,

nitrides, carbonitrides PCBN inserts can improve the chemical resistance to abrasion and impact resistance, but the content is too

High will reduce the hardness of the tool, the tool life is shortened; Cobalt is the most commonly used binder, can increase the sintering degree CBN sintered; Ti

ceramic binder can improve the toughness of PCBN inserts; aluminum and aluminum compounds, CBN particles and other binders react to

Even more firmly bonded CBN particles and improve tool wear; Si and Al, AlN, AlB2 HBN to CBN mixture is an effective catalyst for conversion of the ceramic binder in a

small amount of Al, Si also can enhance inter-CBN bonded, form a continuous ceramic phase; with aluminum

Nickel as a binder PCBN composite sheet conductivity, suitable for using low-cost cutting EDM. Because different adhesive, two features are PCBN inserts tend: one is a

high wear resistance (high content CBN, catalytic binder), the other is a

Good impact resistance (low content CBN, ceramic adhesive).
PCBN tool can process more than the hardness of HRC60 hardened steel, tool steel, tool steel, alloy steel, gray iron, white cast iron, carbide, ceramics and other

traditional tools difficult to machine materials, this is its unique features. PCBN tool appears, for cutting brought

Fundamental change. PCBN cutting tools suitable for general machine tools, special machine tools, automatic lines and CNC machine tools, widely used in military,

automotive, metallurgy roller, bearings, mold and other industries cutting. Carbide Tool PCBN tool life is 5 to 25 times

, High wear resistance and sharpening tool greatly reduces the number of times without re-mill clip PCBN cutting tools are also not the same as carbide tool sharpening

machine clip. PCBN tools can also be carried out without coolant dry high-speed cutting, adapt increasing national environmental requirements and the "low

Carbon economy "requirements to implement" green cutting "to reduce pollution, eliminating the need for cooling costs, benefits the country is machining a good choice,

but now many people are far from this recognition. PCBN cutting tools with affinity iron group element is small, compared with a polycrystalline diamond

Stone tools more suitable for machining steel parts. It is said that PCBN cutting tools in the machining of steel 45 piece also has some advantages, but yet to be

confirmed. PCBN tools can be turning, milling instead of grinding, cutting high accuracy, significantly improve the work efficiency, especially in the automatic line,

CNC

Machine tools and high hardness workpiece advantages more apparent.
PCBN tool use has many advantages, but in the number and range of applications is far enough and wide. Although China from the early seventies of the last century on

the successful development of the CBN, after nearly four decades of efforts, has been produced by CBN superpower, accounted for

More than half of world production, such as the 2008 production of about 280 million karats CBN, exports accounted for about 80% of production, but still lag behind

the development of PCBN cutting tools, advocacy work and also keep up with market standards pace, finished varieties and production tool can not

Meet the processing needs of the industry, resulting in most of the tools used CNC machine still needs to import. Export CBN abrasive, low prices, high prices and

import CBN tools are obviously people do damage to China, this situation should not be allowed to continue. Now, after state authorities

, Universities, research institutions, the majority of technical staff and business working together, we are catching up, but also to fundamentally improve the

situation provided the conditions. In recent years, some domestic tool manufacturers have produced a number of PCBN tool to replace imports

Tools, foreign exchange savings, the use of the results were pretty good. However, the variety, quantity and demand compared with foreign countries there is still a

large gap, and we are the largest producer of CBN's position is very match, we also need to work together to change this situation.
According to the author of the PCBN tool to understand the production and use of some of the situations are PCBN cutting tools for the application of our current

situation and existing problems to make a few solutions:
One should improve domestic PCBN cutting tools on the research system, national authorities should coordinate and organize tool production enterprises to strengthen

cooperation, changing the situation of each enterprise alone, writing PCBN tool size, cutting speed and scope of other aspects of the hand

Volume data for the use of PCBN cutting tool manufacturers and users to provide correct theoretical guidance for the production and promotion of PCBN tool to use with

ease.
Second, as soon as possible to develop national standards for the production of PCBN cutting tools, industry standards and enterprise standards, the implementation of

PCBN cutting tool products (including blade, and the clamping bolt shank portion size) standardization of series production. In this regard, the national authorities

and some companies

Has done a lot of work, the National Standardization Committee in November 2007 launched GB/T2076-2007 "Rules for cutting tools", in June 2008 issued a GB/T21951-2008

"inlay or overall CBN inserts size ", some companies have this standard

Production of a product and ready develop enterprise standards, the work on the production and use of PCBN cutting tools are very important, PCBN cutting tools working

standards should be further strengthened.
 Third, the current, PCBN cutting tools is also less varieties, can not meet the increasing requirements of users. But with the improvement of domestic production

standards, through the joint efforts of relevant departments and enterprises, this phenomenon will soon change, some enterprises have been produced

With the carbide blade size and precision machine folder CBN inserts the same, very easy to use, but the number and variety of PCBN cutting tools should be added.
Fourth, the current price is still relatively high PCBN cutting tools, PCBN indexable inserts machine folder and performance due to different models, each blade

carbide inserts for around 5 to 25 times, which is why some users do not use the PCBN tool one reason. However, because PCBN cutting tools

Carbide tool life is generally 10 to 20 times, and then count to reduce tool change time and improve the efficiency of the overall cost is lower than the actual

carbide cutting tools, machine tools in the general case, the automatic line and CNC machine tools The advantage is obvious, reducing tool change

Number of the benefits to be higher than the price much higher than the cost of the blade, more cost-effective use of PCBN cutting tools. Moreover, PCBN cutting tool

machining carbide tools can not process some of the artifacts. With the deepening of the domestic production of standardized production and technical progress

To reduce the price of PCBN cutting tools but also to continue the work.
Fifth, because PCBN tool to disseminate knowledge about the work is not in place, many manufacturers use including many of the technical staff engaged in machining

PCBN tool performance on poorly understood, many enterprises, especially small businesses, because of the PCBN tools do not understand, generally do not PCBN

Tools, carbide cutting tools in the face of the workpiece can not, you may find someone to consult, be possible to use. Can not find the experts consulted, the only

thing used after annealing the workpiece processing or Subcontractor approach. Therefore, to enhance the knowledge PCBN cutting tools

Advocacy work is necessary.
Six, Henan Province is the production of large CBN, production in the world, universities and research institutes on CBN and PCBN cutting tools in research at the

advanced level in the country. With the superiority of PCBN cutting tools are more and more people understand that its application is inevitable

, Have great development space and great efficiency in the use, promising.