Current status and future of metal cutting tools
First, the status quo of the domestic industry
In 2013, the World Tooling Conference was held in Japan. In the report of the European counterparts, a set of data was given to the global tool consumption level: the global tool market in 2012 was about 16 billion euros (about RMB 130.8 billion). The report divides the tool market into three major regions. The Asian market is the highest at 44%, with a consumption of about 57.5 billion yuan. In Europe, 38% is the second-largest, and the consumption is about 48.7 billion yuan. The tool consumption in the Americas is about 235 yuan. 100 million yuan, accounting for 18% of the global market share.
As far as the Asian market is concerned, among the tool consumption of 57.5 billion yuan, China's tool consumption is more than twice that of Japan, about 5 times that of Korean tool consumption, and about 10 times that of India.
In 2012, China's tool consumption was about 34 billion yuan, which accounted for 59% of the total consumption in Asia, and accounted for 26% of the global tool consumption. Compared with the German tool consumption of about 16.1 billion yuan in the same year and a total of about 15.9 billion yuan in the United States, this figure can be said to be quite amazing.
In 2013, China's tool consumption value dropped slightly, about 33.4 billion yuan, down 1.8% year-on-year; German tool consumption dropped from about 1.975 billion euros in 2012 to 1.94 billion euros, down 1.8% year-on-year; Consumption decreased from approximately $2.63 billion in 2012 to $2.53 billion, down 3.8% year-on-year; Japanese tool consumption increased from 272.1 billion yen in 2012 to approximately 294 billion yen in 2013, an increase of 8% year-on-year.
In China's current tool consumption, high-speed steel tools still occupy a considerable proportion. Although the consumption of cemented carbide tools in China and Japan is comparable, China's high-speed steel tool consumption is about 4.5 times that of Japan. This result shows that the number of traditional machine tools suitable for the use of high-speed steel tools in the market is still very large (according to the statistics of the new machine tool numerical control rate in the first 11 months of 2013 is less than 30%), on the other hand, it also shows that we are large. Some of the traditional knives are still trapped in the quagmire of low-price competition, and it is difficult to save themselves. We can see the composition of the output of high-speed steel tools in China and Japan. It is not difficult to find that about 40% of the high-speed steel tool production value in Japan is a thread cutter. The data shows that in 2012 Japan's thread cutters (floss and die) output value was 26.973 billion yen, accounting for 37% of Japan's high-speed steel cutters. Tools such as taps and dies are currently the product category that is superior to hard alloys in the large number of tools used (although carbide thread milling cutters have a tendency to come later, but due to the limitations of the use of equipment in recent use I am afraid that it is still difficult to surpass the tap); while China's large number of high-speed steel hole machining tools are close to 60% in proportion, it is even more disturbing that about 90% of high-speed steel hole machining tools are high-speed steel twist drills. . That is to say, the high-speed steel twist drill occupies about 54% of the output value of the entire high-speed steel cutter in China. The concentration of varieties is so high that vicious low-price competition is difficult to avoid.
Another problem is the material problem of high-speed steel tools. The proportion of different types of high-speed steel in China and other countries in the world. In foreign countries, high-performance high-speed steel (mainly referred to as high-speed steel containing not less than 5% of cobalt) and ultra-fine grained powder metallurgy high-speed steel (HSS-PM) using powder smelting technology, such as high hardness and wear resistance And the toughness has occupied about 45%-60% of the high-speed steel, and even if we calculate the aluminum high-speed steel is less than 15% (the international aluminum high-speed steel is not used as high-performance high-speed steel), if not high-speed aluminum Steel Our high-quality high-speed steel usage is less than 10%.
Second, product technology development
2.1 Materials and Coating Technology
The development of tool technology is inseparable from material technology, including the development of coating technology to improve the surface properties of materials.
The main development of high-speed steel technology is powder metallurgy high-speed steel. Metallographic comparison of traditional smelting high-speed steel and powder metallurgy high-speed steel. In general, conventionally smelted high-speed steel has large carbide particles in a stripe shape, a tendency to deform during quenching, and limited bending strength and toughness, while powder metallurgy high-speed steel has very small and uniform carbide particles. Rigidity and wear resistance, increased flexural strength and toughness (typically 20 to 50% higher than smelting high-speed steel), suitable for the manufacture of tools subjected to impact loads such as milling cutters, gear shaping knives, planers, and small sections, Thin blade cutter.
Of course, new materials will emerge from time to time. The “SpeedCore” of the German blue gold I (LMT), which was awarded the 2012 Ringier Technology Innovation Award in the metalworking industry, is an example of a new type of material. The material of this hob is neither typical high-speed steel nor hard alloy, and its chemical composition is shown in Table 2. According to the blue flag, because there is no carbon in the new material, the Rolling King is no longer hardened by the metal alloy method but is improved by the age hardening to improve the wear resistance of the material. It is a brand new material technology. Hobbing tools made using this material technology can increase cutting speed by more than 50% compared to conventional high-speed steel hobs and even 30% higher than existing powder metallurgy high-speed steel (HSS-PM).
The current main trend in high-performance materials is particle refinement and the addition of trace elements to improve the properties of the material. Many of us have heard of the magic of nanomaterials. Although the nanomaterialization of tool materials seems to be still in the laboratory stage and has not been commercialized, I believe that in the next 30 years, nanotechnology tool materials Will gradually enter the application phase.
Nanomaterials generally refer to materials having a particle size of 100 nm, that is, 0.1 μm or less. According to considerable data, for solid carbide and indexable inserts, micro-drills and micro-millings with diameters below 0.1 mm currently use sub-nano materials with a particle size of about 0.7 μm, while other tool materials Cemented carbides that can use particles from 1 to 1.3 μm can already be called microparticles. In general, finer-grained cemented carbides have a much higher strength and are considerably more helpful in improving tool performance.
Compared with cemented carbide materials, coating technology is a technology that has developed rapidly in recent years. The methods of tool coating mainly include chemical vapor deposition (CVD) and physical vapor deposition (PVD). Currently, carbide indexable inserts for machining steel and cast iron parts, especially turning inserts, mainly use CVD coatings, while other tools, including solid carbide tools, mainly use PVD coatings. The main trend of coating technology is to control the growth direction and growth size of the grains. Second, add some trace elements to the coating to improve the performance of the coating or improve the friction between the tool base and the workpiece. The third is to do some more fine treatment after coating before coating to improve the cutting performance of the coated tool.
CVD coatings From the current point of view, there are relatively few coatings that can be adapted: mainly for Al2O3 coatings and diamond (PCD) coatings. Although there are not many varieties to be applied since the two coatings (Al2O3) are particularly suitable for processing steel and cast iron, there is large market demand, and the other (PVD) is particularly suitable for lightweight aluminum alloys and aviation. The rapid growth of carbon fiber reinforced composite materials such as aerospace and wind power, so this technology still has great development prospects. The authors predict that Al2O3 coatings should be developed towards obtaining a thicker a-phase Al2O3 layer, controlled nucleation oriented growth techniques for grains, grain refinement techniques, and reducing and eliminating microcracks and droplets in coatings.
The development of PVD technology is diversified due to its own characteristics. The author predicts PVD coating--the aspect will improve the wear resistance of the coating, enhance the heat resistance of the coating, and reduce the friction of the coating-chip friction pair or the coating-worked surface friction pair. It can reduce the characteristics of cutting heat transfer to the tool; on the other hand, it will improve the mechanical and chemical properties of the coating itself by refining the coated grains.
It should be said that CVD and PVD each have their own advantages, sometimes making it difficult for tool designers. However, there are always some smart people who can find a way to balance the two or to find a balance between the two.
Walter Tools has introduced the new material WMPS20S, which is mainly used to process stainless steel. Since stainless steel machining is more prone to bond wear of the tool or scaled surface of the machined surface, it is important to prevent the two-pair friction pair of the tool-workpiece and the tool-chip. Therefore, the tool is usually sharper when machining stainless steel. However, the CVD coating requires a relatively large blunt circle before coating, and the tool is always not sharp enough. Walter's WMP20S coating is about 10μm, neither as thick as 20μm for CVD nor as thin as 5μm for PVD. This takes into account the two characteristics that were previously opposed to each other (ie, sharp cutting geometry and anti-wear CVD chemical coating). It has a fairly sharp cutting edge and a very good wear resistance.
2.2 cutting edge technology
The edge design, including the passivation design, is another important factor in ensuring the performance of the cutting edge. Chip breakers are a common concern in turning inserts. But in the past, due to process limitations, diamond or cubic boron nitride blades have almost no chip breakers. With the continuous development of manufacturing technology in recent years, laser-engraved recessed chip breakers or welded-made protruding chip breakers have appeared on the blades of superhard materials. Kennametal developed the KB5610 TM and KB5625 TM with the chip breaker by combining the special chip breaker type with two high-performance PCBN materials, allowing customers to fully control the chip winding problem that occurs when the car is hard.
2.3 blade clamping technology
The stable clamping of the blade is one of the prerequisites for smooth cutting. In recent years, various tool companies have been able to say that the blade clamping method is full of flowers, adding a lot of bright colors to the tool products.
In rough machining characterized by large cutting depth (4-10mm) and large feed (0.4-1.0mm/r), in order to cope with interrupted cutting and high cutting load, the upper press type arbor clip is conventionally selected. Processing with large size single-sided inserts. This is because the blade of the single-sided blade is small, which makes the blade economical, and the upper platen may also hinder the smooth discharge of the chip. To solve these problems, Iskar developed an innovative dovetail slot positioning combined with a lever-type clamping mechanism. The new system ensures a high-rigidity clamping of the double-sided inserts for a secure grip; while avoiding the upper-pressure clamping structure that blocks the flow of chips. The DOVE IQ TURN blade, which is named as the DOVE IQ TURN, has wedge-shaped clamping on both sides and the clamping system is stable. The dovetail positioning groove fits the corresponding positioning portion of the blade, which avoids the blade being upturned due to the cutting force during the machining process.
Iskar's new pentagonal blade cutting tool also takes a different grip. This is named as the IQ five-pointed tyrants series (PENTAIQGRIP) with five cutting edges. Compared with the classic five-pointed tyrants, this series of blades has deeper grooving and larger cutting diameter. The IQ five-pointed King's knife series is also positioned with the blade dovetail groove so that the blade and the body are in surface contact, and the clamping will be more secure and stable. The blade is capable of bearing the lateral force for finishing.
The grooving and cutting knives of curved elbows or right-angle elbows are a way to keep the grooving blades away from chip wear. Walter Cut's SX series of grooving and cutting knives, Isa's vertical self-clamping single-head inserts (TANG-GRIP) for end grooving avoid the usual upper jaw design in other clamping systems. Therefore, the chip removal is very smooth in the blade processing, and it should be very suitable for deep groove processing or cutting.
Sandvik Coromant's iLock technology is another structure that improves blade positioning and clamping. In turn, such structures are mainly used for profile turning, threading, etc., and require two-way walking, and the original conventional clamping causes slight shaking.
In 2013, the Xiamen Jinlu Sanjian 55° blade or the three-point 35° blade, which was ranked first in the metal processing industry's Ringier Technology Innovation Awards, also used the blade clamping structure to increase the effective cutting edge.
2.4 Tool Cooling Technology
New tool cooling technology is mainly used on difficult materials. Mainly divided into high-pressure cooling, liquid nitrogen cooling, and atmospheric cooling.
A typical representative of the current high-pressure cooling technology is Seco Tools' new Jetstream Tooling Duo. Jetstream is a technology introduced by Seco Tools in the past few years. It directly transports cutting fluid between the chip and the rake face through the cutting fluid that is sprayed at high speed against the rake face, making the cutting fluid The cooling and lubricating effect directly acts on the first deformation zone where the cutting temperature of the rake face is the highest, while increasing the deformation of the chip makes the chip breaking easier. In recent years, this type of technology has become a magic weapon for major international tool giants to deal with difficult materials. The dual-flight technology is an upgrade in the original fly-flow technology. It not only continues to output cutting fluid at high speed along the rake face but also increases the cutting fluid that is jetted at high speed on the flank. Similar to the fly-flow technology, this new cutting fluid is delivered directly between the flank and the machined surface, reducing the friction in the second deformation zone and slowing the wear of the flank of the tool. It can be said that the double-flight flow technology reduces the friction of the second and second deformation zones at the same time, so that the main wear such as crater wear, bond wear, flank wear, and stripe wear is greatly reduced, and the cutting edge is cut. The large temperature reduction reduces the possibility of plastic deformation, and predicting the contribution of this technology to reducing tool wear will be significant.
The difference is the atmospheric pressure internal cooling system of Kennametal, which they named BeyondBLASTTM. Kenner's atmospheric cooling is carried directly through the cooling passage inside the tool to the cutting fluid directly to a position very close to the tip. Kenner said that this technology avoids large-scale modifications to the machine because the machine using this technology does not need to withstand high pressures.
Kennametal has also developed this on milling cutters.
Beyond BLAST technology. Beyond BLAST cutters open the coolant tank at the joint of the milling cutter and the blade and directly transport the coolant through the blade to the part where the blade cuts the workpiece material, ensuring the effective transmission of the coolant, reducing the cutting temperature and improving the lubrication ability.
Walter tool developed a fluid with the machine tool builder
Nitrogen cooled cryogenic system technology. It can be combined with oil mist lubrication (MMS) according to different processing requirements to reduce friction and adhesion between the tool and the chip. According to the machine tool manufacturer, the liquid nitrogen at a temperature of minus 196C flows through the main shaft, the shank and the pipe inside the cutter body in the low-temperature machining system of the machine tool, and then passes through the outlet in the cutting insert to reach less than 1 mm from the shear plane. . Such a low-temperature coolant has an extremely high cooling capacity for the high temperature generated during cutting and can prevent the cutting heat from being transmitted to the cutter cutting edge.
The reason why this system is efficient is that the center of the cutting tool material is directly cooled by the spindle so that the cooling effect is concentrated on the blade body. According to Walter, MAG's liquid nitrogen cooling system can significantly improve production efficiency when difficult machining of difficult-to-cut materials such as titanium, nickel-based alloys, ductile iron or compacted graphite iron, while Walter's Cryotec cutters Help liquid nitrogen flow directly to the cutting area of the tool. Especially in the aerospace, energy industry and automotive industries, the use of Walter Cryotec tools can significantly increase cutting speed and extend tool life. The data shows that the use of this technology to mill vermicular graphite iron (CGI) can increase the cutting speed of cemented carbide tools by 60% and the cutting speed of polycrystalline diamond (PCD) tools by three times.
Cooling of the overall tool is also a problem. The flagship JetSleeve* cooling king thermal chuck can spray the coolant directly to the cutting edge. Its 16 annular jets of different angles form a jet, which reduces the use of coolant by 70% and effectively extends tool life. Improve the quality of the machined surface. At the same time, it prevents the chips from coming into contact with the cutting edge, so that no secondary processing costs are incurred.
Similar to the blue flag of the JetSleeve cooling king hot chuck system is Hanmer's Cool Jet. Recently, Hanmer has developed a new system called CoolFlash. The end of the CoolFlash chuck has a disc on which an annular slit is formed by the difference in diameter in the direction of the cutter. The coolant accumulates in the reservoir at this point, creating a very high pressure. From this small chamber, the high-pressure coolant flows through the annular slit like a waterfall through the entire tool shaft, just like a closed jacket is placed on the tool to protect it from air turbulence. At the end of the tool shaft, the coolant is pressed into the sipe, washed, and then directly rushed to the cutting edge of the tool at high speed to cool it (in the process, the coolant is not atomized). The Cool Flash system has the obvious advantage of not requiring an extra sleeve or a separate auxiliary device or having to perform additional operations during tool loading for optimum cooling. The Hanmer hot-mounted chuck with the waterfall system Cool Flash can still handle the tool normally, and the original stability, rigidity, and fit of the chuck remain unchanged.
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