Super hard diamond tool and its application in hard turning

Super hard cutting tool and its selection

Super hard tool adoption and diamond tool organs and geometrical parameters is to achieve a basic element of hard turning, is to how to select super hard cutting tool materials design fair tool organs and geometric parameters on the same hard turning implementation is very important.

1, super hard cutting tool material and its selection

Coated cemented carbide

In better toughness of cemented carbide cutting tools coated with one layer or multilayer wear resistance of tin, TiCN and TiAlN and Al3O2 etc., coating thickness for 2-18 μ m, coating usually has a much lower than the tool material and workpiece material heat conduction coefficient, weakened the tool substrate hot dip; on the other hand can effectively improved the cutting process of friction and adhesion dip and down cutting hot born.

The coating can be divided into 2 types: physical vapor deposition (PVD) and chemical vapor deposition (CVD). PVD diamond coating (2~6 m) mainly includes TiN, TiCN, TiAlN etc., the composition still added ceaselessly, such as

Ultra hard diamond tool and its application in hard turning process and the data of the application of super hard cutting tool and the diamond cutting tool

TiZrN. Tin and tic coatings of the highest pressure resolution can be reached and 3775MPa 3580MPa, TiAlN coating due to the elastic modulus of the poor rustic reliable data and have not to the correct pressure stress value, high speed cutting experimental results section TiAlN performance is the best. Figure 1 for these 3 kinds of coating hardness with the temperature change of the scene, at room temperature, the highest hardness, when the temperature across the [Y, \ time, the hardness of TiAlN coating is higher than the TiCN and TiN coating. Figure 2 for the processing of nickel based superalloy Inconel178 with 2 kinds of diamond cutting speed v1=193.5m/min and v2=380m/min under the conditions of tool life test shows that the cutting performance of TiCN and TiAlN coating is better than the TiN coating.

Fig. 1 Relationship between PVD coating hardness and temperature Figure 2 the tool life of Inconel178

Although the PVD coating shows many advantages, some of the coatings, such as Al2O3 and diamond, tend to adopt the CVD coating technique. Al2O3 is a kind of heat resistant and oxidation resistant coating, which can separate the heat from the cutting. Through the process of CVD coating technology, but also the advantages of various types of coating, to reach the best cutting results, to meet the needs of the cutting process. For example. TiN has the characteristics of low friction, can reduce the loss of coating tissue, TiCN can decrease the flank wear, TiC coating hardness is higher, Al2O3 coating

Ultra hard diamond tool and its application in hard turning process and the data of the application of super hard cutting tool and the diamond cutting tool

The layer has excellent thermal insulation effect.

Compared with cemented carbide tool, the coating has great improvement in strength, hardness and wear resistance. Turning hardness in the HRC45~55 of the workpiece, the low cost of coated carbide can be achieved at high speed turning. In recent years, some manufacturers to improve the coating materials, such as the style, so that the performance of coated tools has been greatly improved. Such as some manufacturers in the United States and Japan adopted Swiss AlTiN coating materials and coating of the patent technique birth of blade coating, high hardness of HV4500~4900, in 498.56m/min speed cutting hardness HRC47~58 of die steel. In the turning temperature up to 1500~1600 degrees C still hardness does not drop, not oxidation, blade life is 4 times the general coating blade, and the cost is only 30%, and with a good output.

Ceramic material

Ceramic tool materials with the composition of organs and pressing process of tempered, especially the progress of nanotechnology, the toughening of ceramic cutter become possible, in the near future, ceramic may following the high-speed steel, carbide back caused the third revolution of machining. Ceramic tool has a bending strength of high strength and high hardness (HRA91~95) for 750~1000MPa), good wear resistance, good chemical stability, anti bonding performance of the wonderful, the friction coefficient is low and the price is low and

Point. Not only that, the ceramic cutting tool also has a high temperature hardness, hardness of 1200 degrees HRA80 to reach C.

Normal cutting, the ceramic cutting tool life is extremely high, cutting speed can be more than 2~5 times the hard alloy, especially suitable for high hardness data processing, precision machining and high speed machining, cutting hardness up to HRC65 of all kinds of quenching

Ultra hard diamond tool and its application in hard turning process and the data of the application of super hard cutting tool and the diamond cutting tool

Steel and hardened cast iron etc.. Commonly used are: alumina based ceramics, silicon nitride based ceramic, metal ceramic and whisker toughening ceramics.

Alumina based ceramic tool than the hard alloy has higher red rigid, high-speed cutting conditions of cutting edge are generally not occur plastic deformation, but its strength and toughness is very low, to improve its toughness, progressive resistance impact performance, who can join ZrO or tic and tin thick muddy thing. Another style is to intervene in the pure metal or silicon carbide whiskers.

Compared to silicon nitride based ceramics in addition to the high red hardness outside, also has a wonderful toughness, and alumina based ceramic and its defect is in steel processing are prone to high temperature diffusion, the increase of tool wear, silicon nitride based ceramic primary application in intermittent turning gray cast iron and milling gray cast iron.

Metal ceramic is a carbide as matrix materials, the tic for the first hard phase (0.5 to 2 μ m), they through the process of CO and Ti binder is united in wedlock, is a hard alloys with similar tool, but it has lower affinity, brilliant friction and good wear resistance. It is practice hard alloy can withstand higher cutting temperature, but the poor rustic hard alloy impact resistance, strong cutting toughness and low-speed feed of the eve of the strength. 

In through a large number of study, improve and adoption of new manufacturing processes, the flexural strength and toughness were the very big progress, such as Japan Mitsubishi Metal Co., Ltd revelation of a new type of metal ceramic nx2525 and Swedish sander Vick's revelation of metal ceramic blade new CT series and coating metal ceramics blade series, the grain diameter of the subtle to 1 μ m or less, the bending strength and wear resistance are much higher than common metal ceramic, greatly broaden the limitations of their application.