Engineered Flooring,Engineered Wood Flooring,Laminate Flooring Hongda Anxin Decorative Material Co., Ltd. , http://www.hb-flooring.com
A superhard cutting tool comprising a main tool <br> <br> superhard diamond tools and cubic boron nitride tool, wherein the synthetic diamond compact (PCD) cutting tool and the cubic boron nitride composite (PCBN) cutting tool metal dominant PCD Cutting tool PCD metal cutting tool can use high hardness, high wear resistance, high thermal conductivity and low friction coefficient of PCD material to achieve high precision, high efficiency, high stability and high surface finish of non-ferrous metals and wear-resistant non-metallic materials. . Such tools are mainly structurally divided into welded PCD cutters and indexable PCD inserts. In recent years, the fastest-growing variety of welded PCD tools is PCD tools with standard tool holders, such as PCD cutters with handles, PCD files, PCD reamers, etc. The type of tool holder is mainly cylindrical handle, taper shank and HSK handle. . This kind of tool (especially multi-toothed tool) is characterized by small beating of the cutting edge (such as the cutting edge of the HSK shank PCD milling cutter with a blade length of 30mm is only 0.002mm), especially suitable for various colored Large-scale high-speed machining of forming surfaces, holes, stepped holes, etc. of metal parts. For example, PCD high-speed milling cutters (six-blade, diameter 100mm) with aluminum base cutters, with a maximum speed of 20,000r/min, above, cutting speeds of up to 7,000m/min. The indexable PCD insert is made by inserting a PCD blank on the carbide indexable insert and then sharpening it. It can be clamped on the cutter bar, tool holder or cutter head of various CNC machine tools. High-reliability high-volume processing. With the increasing popularity of CNC machine tools, machining centers and automatic production lines, the use of indexable PCD inserts is increasing, and the tool durability can be increased by several times compared with cemented carbide tools. PCBN metal cutting tools PCBN metal cutting tools can also be divided into two types: welded PCBN tools and indexable PCBN blades. The welded PCBN tool is obtained by welding the PCBN tool blank on the steel substrate, mainly including turning tools, boring tools and reamers. PCBN tools are mostly used for the processing of wear-resistant ferrous metals, so the tool nose angle should not be too small, the tool rake angle is generally -5° to 5°, the back angle is generally 3° to 10°, and the negative cutting is generally negative. Chamfer. The PCBN inserts (mainly for the inserts and milling inserts) of the indexing structure are typically welded to a corner of the indexable carbide insert with a PCBN blank that is sharpened. Considering the expensive and re-grinding of the blank, it is generally only made into one tip. With the improvement of the quality of the welding process, the shear strength can reach 0.78kg/m2. As the size of the PCBN blank becomes smaller, the price of the non-reground PCBN insert is also reduced.
Second, typical superhard cutting tool <br> <br> Hard machining applications, due to the car instead of grinding PCBN tool has a very high hardness and red hardness, high hardness can be processed to obtain a good surface roughness of the parts, so Turning hardened steel with PCBN tools can achieve “car grindingâ€. Application examples such as machining of gear holes of automobiles and motorcycles, such parts are generally 20CrMnTi, carburized and quenched, surface hardness is 60-62HRC, gear hole precision is IT6, surface roughness Ra≤0.8μm. The traditional processing technology is: machining -> heat treatment -> grinding. The processing technology of “hardening by car†with super-hard tools is: roughing->heat treatment->finishing. The new process can greatly improve the processing efficiency and reduce the processing cost. The original grinding process can only process 100 pinions, and now it is PCBN tool turning (cutting parameters V=60～120m/min, f≤0.12mm/r) , ap ≤ 0.1mm, a class can process 400 pinions, in addition, the processing cost allocated to each gear has also decreased.
High-speed cutting, high-stability processing In the automobile engine production line, the cylinder hole finishing of gray cast iron cylinder is one of the key processes, requiring high dimensional accuracy of cylinder bore machining, small surface roughness value and good stability; Fast, requires high cutting speed (usually V ≥ 500m / min), long tool life (number of machining holes ≥ 1000), and the blade life of multiple stations such as chamfering, stop, coarse and fine, should meet the durability requirements . High-speed cutting and high-stability machining of engine cylinder bore can be realized by PCBN tool. Typical cutting parameters are: V=500m/min, f=0.2～0.4mm/r, ap=0.2～0.7mm; machining surface roughness Ra≤1.6μm, tool life>1,000 pieces. High-speed, high-stability, low-roughness processing and mirror processing of non-ferrous metals When PCD tools are used to process non-ferrous metals, the hardness of the diamond is high, the surface and metal affinity are small, and the tool is generally polished into a Mirror Surface, which is not easy to produce built-up edge. The dimensional stability and surface quality of the process are very good, and the tool life is also long. For example, the copper commutator that uses the PCD tool to machine the motor commutator, the typical cutting parameters are: V=300m/min, f=0.08mm/r, ap≤0.15mm, the machined surface roughness Ra0.1～0.2μm, the tool The life is > 5,000 pieces, while the carbide tool can only process a few pieces. Using PCD tools to process a variety of silicon-aluminum alloy parts, surface roughness Ra ≤ 0.1μm, tool life can reach several thousand to tens of thousands, especially suitable for large-scale production of automotive and motorcycle parts. With single crystal diamond tools, mirror spherical processing can be realized on ultra-precision lathes. The machine tool adopts ultra-precision gas static pressure spindle and rotary table, the runout is ≤0.3μm, and the workpiece adopts high-precision pneumatic chuck, which can realize fast and high-precision positioning. When processing oxygen-free copper material, the surface roughness Ra≤0.025μm, roundness ≤0.3μm; when processing aluminum parts, the surface roughness Ra≤0.025μm. Dry cutting, cleaning processing using PCBN tool to process boron-containing cast iron cylinder liner, cutting parameters: V=200m/min, f=0.1mm/r, ap=0.2～1mm, machining surface roughness Ra≤1.6μm, precision IT6 The tool life of the two sharpenings is >100 pieces, which can achieve "car grinding". Due to the dry cutting, the cutting (grinding) cutting liquid and the grinding wheel ash are avoided to pollute the environment, and the chips can be recycled and reused, which meets the requirements of clean production. The above mentioned tool prices are more expensive. Some small manufacturers will not buy large quantities due to cost issues.
Third, China's new cutting tools
This rare earth-added cemented carbide is one of the new varieties of tool materials. The rare earth element refers to the atomic number 57 to 71 (from La to Lu) in the periodic table of the chemical element, plus 21 and 39 (Sc and Y), a total of 17 elements. Adding certain rare earth elements to the traditional carbide grades in a certain way can effectively improve their mechanical properties and cutting performance. China is rich in rare earth elements and research and development of rare earth hard alloys, ahead of Other countries. Rare earth hard alloys for the following grades have been developed: YG8R (equivalent to ISOK30 grade), YG6R (K20), YW1R (M10), YW2R (M20), YT5R, YT14R (P20), YT15R (P10), YS25R ( P25). There are also mines and geological tools No. YG11CR. After rare earth elements such as Ce and Y are added to the YG8, YT14, and YW1 cemented carbides, rare earth hard alloys YG8R, YT14R, and YW1R are formed. YG8R is mainly used for rough machining of cast iron and non-ferrous metals; YT14R is mainly used for semi-finishing of steel; YW1R is a general-purpose grade, which can be used for semi-finishing of various workpiece materials. After testing, the microstructure of the cemented carbide is relatively dense after the addition of rare earth elements; the room temperature hardness and high temperature hardness are improved; the fracture toughness and bending strength are significantly improved, respectively, by 20% and 10%. Rare earth elements are abundant in nature and the price is not high. Adding to cemented carbide can obviously improve mechanical, physical properties and performance, so it has broad application prospects.
Wear Resistance and Service Life Test of Rare Earth Cemented Carbides Through some tests, the wear resistance and service life of YG8R, YT14R and YW1R inserts have been improved to different degrees compared with the original blades without rare earth elements.
Compared with the original blade without rare earth elements, the rare earth cemented carbide is subjected to the impact on the spline shaft steel until the tool tip is damaged. After repeated tests, the YG8R, YT14R, and YW1R blades can withstand an increase of 1 to 2 times more than the YG8, YT14, and YW1 inserts before the tool tip is broken. Rare earth elements are present in (W,Ti)C or (W,Ti,Ta,Nb)C solid solution, which can strengthen the hard phase; and can inhibit the uneven growth of WC grains, making them tend to be uniform, and the average grain size Decreased. A small amount of rare earth elements is also dissolved in the binder phase Co to strengthen the binder phase. The rare earth element is enriched at the phase interface of WC/Co and the interface between (W, Ti)C/(W, Ti)C and other phases. It is often combined with impurities S and O to form compounds such as RE2O2S, which improves the cleanliness at the interface. And improve the wettability of the hard phase and the binder phase. As a result, the impact toughness, bending strength, and impact resistance of the rare earth cemented carbide are remarkably improved. Its hardness, wear resistance and resistance to diffusion and oxidation on the surface of the tool are also improved. After electron microscopy, it was found that the rare earth carbide insert has a cobalt-rich surface during cutting, so the friction coefficient between the chip and the workpiece and the tool can be reduced, thereby reducing the cutting force.
Development and current status of tool materials
In modern machining, tool materials are used most in hard alloys and high-speed steel, almost half of each. The invention and application of high-speed steel has a history of a whole century, and cemented carbide has been for half a century. However, both have developed many new varieties, and their performance has been continuously improved, playing an important role in mechanical processing. In recent years, with the rapid development of CNC machining technology and the widespread use of CNC machine tools, high efficiency, high stability and long life processing are required. The application of superhard tools is also becoming more and more popular, and many advanced cutting concepts have been introduced, such as high-speed cutting, hard machining, high-stability machining, car grinding, dry cutting, etc. Superhard tools have become an indispensable tool in modern machining.