Machinery manufacturing is the direction of high speed machining, the intelligent processing, environmental protection, in along with the continuous renewal of manufacturing to product material, treat the requirement of increasing the hard processing material, higher request for processing cutting tool performance, the high efficiency, high wear resistance and high toughness, high accuracy and high stability performance is tool will be development trend. Cutting tools gradually toward high efficiency, hard machining, dry cutting, high precision metal cutting development direction, CBN&PCBN tool is high precision machining and high efficiency machining required tool series.  

1. Machining properties and categories of CBN tools

 Although CBN inserts is expensive, its advantages has been particularly prominent, in the pursuit of quality and processing efficiency of the industrial age, CBN cutting tool cutting tool is very good, in the car of machining and the important position in the field of aviation, And in the use of high precision machine tools, manufacturers can fully play to the advantages of CBN insert, for manufacturers to improve production efficiency and reduce processing costs.

CBN tool, belongs to a kind of superhard tool, is CBN micro powder as raw material, in a small amount of binder under the action of the use of ultra-high temperature and high pressure technology manufactured.  Because the hardness of CBN tools is very high, it is very suitable for machining hardness greater than HRC50 and wear resistant materials.  

CBN tool can be used to cut hardened steel (bearing steel, die steel, etc.), cast iron (gray cast iron, nodular cast iron, high chromium cast iron, alloy wear iron, etc.), high speed steel, hard alloy, superalloy and other materials, in the ferrous metal processing has great advantages.  

It should be noted that if the processing material is a soft family of metal or non-metal system, it is not suitable to use CBN tool to process.  The CBN tool is recommended only when the hardness of the material reaches a certain level (HRC>50).  

Common CBN insert structure: in general, the CBN tool commonly used in turning mainly the following structural forms: solid CBN insert, welding CBN indert, which welding CBN insert and includes the whole welding insert and composite welding insert.

(1) Solid CBN insert.  The solid insert is sintered from CBN micro powder, with many cutting edges, the upper and lower tip can be used for cutting, and the utilization rate of the blank is high.  And the blade bending strength is large, can withstand high speed cutting with large cutting depth, suitable for continuous, weak discontinuous, strong discontinuous cutting environment, wide applicability, can meet rough, semi-finish and finish processing.

(2) Solid welding type CBN insert.  Through welding form, high welding strength, center hole positioning, can directly replace the coating blade.  Suitable for cutting depth <2mm working conditions, weak discontinuous and continuous processing environment, meet the semi-finish and finish machining use.

(3) Composite welding type CBN insert.  The small CBN composite block after cutting is welded to the hard alloy matrix, so as to form a variety of turning blade and boring blade, generally only one edge available, mainly used for finishing conditions.  

 Such as solid CBN inserts, just have good wear resistance and impact toughness, in high hardness machining area occupied the absolute superiority, such as processing large cast iron, hard to avoid can appear the casting defects such as sand inclusion, porosity, for cutting tool machining difficulty increases, In particular, the hardness of HRC55 above the material is more difficult to process.

The solid CBN inserts has both sides of the cutting edge processing to reduce the cost of production of the tool, the solid CBN inserts height of 7.76mm thick, than the traditional tool 3.17mm thick, this insert can be installed on the standard handle, general performance is better, more convenient.

CBN insert is more suitable for high hardness workpiece processing

CBN tool is more suitable for machining parts with high hardness, in fact, the hardness of the processed parts is generally HRC46, if the CBN tool machining hardness is lower than HRC46, it is unneessary to use CBN.

In rough machining, the use of the whole CBN insert can be larger than the ordinary insert cutting, improve production efficiency, CBN insert in the rough machining field first proposed to increase the amount of cutting, improve efficiency, insert cutting depth can reach 8mm, linear velocity up to 125m/min, there will be no insert falling phenomenon in the finishing field, Quenched steel workpiece is the most typical, the general hardness is above HRC46, and the special hardness is above HRC58. For traditional ordinary alloy cutting tools cannot perfectly fit for machining, easy processing for CBN cutting tool processing, quenching steel finishing more commonly, small machining allowance, with composite welded CBN inserts can play to its superior performance, in order to more affordable, tend to choose the first insert more complex welding CBN inserts.

CBN tools Mark