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.
TM
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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