The crucial technology of high speed cutting reachs application

The cutting of notional high speed of cutting of 1 high speed (HighSpeedCutting) it is an opposite concept, heretofore still has no to be limitted exactly. High speed cutting shows than groovy cutting speed and feed speed tower above the cutting of 10 times machines 5 times ～ normally, also call freeboard sometimes fast cutting (Ultra2highSpeedCutting) . Also have reach main shaft rotate speed 10000r/min ～ 60000r/min, above of 40m/min of fast feed speed, above of 10m/min of average feed speed, acceleration is more than the cutting of 1g to machine a definition to be high speed cutting. To different workpiece material and treatment craft, speed of high speed cutting (the linear velocity that cutting machines, unit M/min) range is distinct also. Differentiate by workpiece material, when achieving above of above of 1100m/min of above of 1000m/min of material of 380m/min above, cast-iron 700m/min above, copper, aluminous material, plastic 1150m/min to rolled steel when cutting speed, be considered as limits of appropriate speed of high speed cutting; By treatment craft differentiates, limits of speed of high speed cutting is: 7000m/min of turning 700m/min ～ , 6000m/min of milling 300m/min ～ , auger cut 200m/min ～ 1100m/min, 10000m/min of grinding 5000m/min ～ . Concept of high speed cutting is Luo Meng of Sa of German cutting physicist (CarlSalomon) put forward 1931, people is commonly used now " Sa Luomeng curve " will express. He thinks, inside limits of groovy cutting speed, cutting temperature as cutting speed rise and lift, certain workpiece material correspondence has rate of a critical cutting, here cutting temperature is highest, but after cutting speed exceeds critical value, cutting temperature not only do not rise to drop instead. To material of workpiece of avery kind of, put in limits of a speed, inside this limits, because cutting temperature is too high, cutting tool data cannot support, cutting treatment cannot undertake, this limits says for " dead cereal " . If cutting speed can be crossed " dead cereal " , work in high speed area, undertake high speed cutting likely with existing cutting tool, cutting temperature and groovy cutting are basic and identical, reduce cutting man-hour greatly thereby, raise a machine tool to manufacture efficiency substantially. 1.

The speed of cutting of characteristic high speed of technology of cutting of 2 high speed than groovy cutting speed almost tower above an amount class, different of its cutting mechanism at groovy cutting. As a result of the change of cutting mechanism, make technology of high speed cutting has following characteristics. 1.

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1 cutting force is small because cutting rate is high, cut bits to pour out of speed to accelerate, cut bits to pour out of obstruction to decrease, cutting is out of shape reduce, make cutting force reduces 30% above than groovy cutting thereby, especially the extent of radial cutting muscularity that main shaft bearing, cutting tool, workpiece gets decreases, special agree with machine Bao Bi kind the workpiece of rigid difference, the wing wainscot that goes up like the plane. 1.

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2 workpiece heat is out of shape small when high speed cutting, the heat in metal cutting of 90% above has not enough time to pass what be poured out of by high speed to workpiece to cut bits to take away, workpiece accumulates quantity of heat little, workpiece temperature rise won't exceed 3 ℃ , maintain cold conditions basically, won't bring about heat to be out of shape as a result of temperature rise, special agree with treatment slightness heats up the workpiece that change easily. 1.

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3 material excision leads what follow cutting rate high to rise, feed rate also rises 5 times ～ accordingly 10 times, the 3 times ～ that the material excision rate inside unit time can amount to groovy cutting 6 times, apply to material to excise the circumstance with rate big demand, make in aerospace, car and mould wait for a domain, technology of high speed cutting already became optimal of treatment whole component part to make a technology. The fair of European machine tool that 2001 German Han Nuowei holds (EMO) go up machining center of vertical of the Unipro25 that exhibiting Holand Unisign company makes 5 axes (800mm of journey of X journey 1000mm, Y) , 100kW of power of electric main shaft, 25000r/min of top rotate speed, 90Nm of the biggest torque, the material excision rate of its milling aluminium alloy already amounted to 8000cm3/min ～ 10000cm3/min. 1.

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Vibration of 4 machining complex is little, can realize treatment of high accuracy, low surface roughness to be when high speed cutting, of the machine tool stimulate Zhen Pin rate is very high, was head and shoulders above " machine tool, cutting tool, workpiece " the natural frequency limits of machining complex (50Hz ～ 300Hz) , make treatment process smooth, vibration is little, can realize treatment of high accuracy, low surface roughness. High speed cutting machines acquisition exterior quality to often can amount to grinding level, accordingly constant but the finish machining working procedure after leave out milling. For example, the machining center of horizontal of DHP50 high accuracy that Swiss DIXI mechanical company produces, 500mm of workbench 500mm × , double tray, the journey is 700mm of × of 700mm × 700mm, main shaft rotate speed is 12000r/min, power is 25kW, knife storage capacity measures 65, 4s of the time that change a knife (T2T) , 6s (C2C) , fixed position precision 4 μ M, repeat fixed position precision 2 μ M (by ISO23022 standard) , measure resolution 0.

5 μ M. High speed cutting agrees with especially the treatment of the domain such as optics. 1.

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5 if stainless steel of hard steel of tall manganese steel, temper by dipping in water, austenite, composite material and wear-resisting are cast-iron,can process data of difficult treatment of difficult treatment material the cutting that wait is machined not only cutting efficiency is low, and cutting tool life is brief. When high speed cutting, because cutting force is small, cut bits to be out of shape resistance is little, cutting tool wears away small, reason can process data of a few difficult treatment. For example, the nickel that uses in great quantities in aviation manufacturing industry base material of alloy, titanium alloy, big, hardness machines intensity high, impulse withstandly, easily sclerotic, cutting temperature is high, cutting tool wears away serious, use very low cutting rate commonly in groovy cutting. If use high speed cutting, its cutting rate can rise 100m/min ～ 1000m/min, not only can raise a machine tool to manufacture efficiency substantially, and can reduce cutting tool effectively to wear away, raise workpiece surface to machine quality. 1.

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The green that 6 high speed do cutting to be able to realize treatment process makes high speed do cutting to process the technique that any cutting liquid do not use in the process in cutting namely, a kind of technology that is pair of traditional cutting means innovates. It is opposite at wet cutting character, it is a kind of green cutting that controls pollution from fountainhead and clean workmanship, it removed the uses pair of outside systems to cause negative effect of cutting fluid. Current, the workpiece material that can realize high speed to do cutting has steel of bearing of cast-iron, aluminium alloy, scroll to wait. 2. The cutting of crucial technology high speed of high speed cutting is a complex systematic project. High speed cutting is cutting speed not merely rise, the technology that its development involves a lot of field such as machine tool, cutting tool, craft and material cooperates to innovate with the technology. 2.

The machine tool of high speed cutting with good specifications of machine tool of cutting of 1 high speed is the premise that realizes high speed cutting and key, and the system of high speed feed with the high speed main shaft that has high accuracy and control expensive precision, it is the crucial place of technology of machine tool of high speed cutting. 2.

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Main shaft of high speed of main shaft of 1 high speed is the core component of machine tool of high speed cutting, precision of the cutting rate that deciding machine tool of high speed cutting to be able to be achieved greatly, treatment and applied limits. Current, comfortable at the machining center of high speed cutting top rotate speed is more than its main shaft commonly 10000r/min, some is as high as 60000r/min ～ 100000r/min, be general accuracy machine tool 10 times the left and right sides; Advocate 80kW of ～ of electromotor power 15kW, in order to satisfy the requirement of milling of high speed turning, high speed. As electric drive technology (technology of frequency control technology, electromotor vector control) rapid development, machine tool of high speed numerical control advocate the rigid structure of transmission gets great simplify, cancelled positive drive and belt transmission, the transmission configuration that uses machine tool main shaft and unifinication of main shaft electric machinery (namely main shaft of so called report) , realized a machine tool " 0 drive " . Bearing is the crucial part that decides main shaft life and negative charge. The bearing that electric main shaft uses basically has scroll bearing, fluid static press bearing and bearing of magnetism in suspension. Scroll bearing has stiffness because of its function of tall, high speed rate of concise, standardization mixes good, structure high the advantage such as price moderate, get applied the most extensively in electric main shaft. Scroll bearing is when high speed circumgyrate, it is very important to lubricate, current, electric main shaft basically uses two kinds of lubricant means: Grease lubricates and oily - gas is lubricant. Although,oily mist lubricates valence cheap, but because its pollute an environment, damage jockey person health, do not accord with green is made and can develop a principle continuously, company of foreign report main shaft already was used no longer. The fluid is static press bearing (include gas static pressure bearing and liquid are static press bearing) to be not contact bearing, have wear away small, life is long, rotate precision is mixed high damp character is good wait for an advantage. Gas is static press rotate speed of bearing report main shaft to be able to be as high as 100000r/min ～ 200000r/min, defect is stiffness difference, carrying capacity is small; The liquid is static press bearing stiffness tall, carrying capacity is strong. Bearing of magnetism in suspension calls magnetic force bearing again, also be blame contact bearing, did not wear away, need not any lubricating. Current, the manufacturer that produces main shaft of report of bearing of magnetism in suspension has German GMN company, Swiss IBAG company and institute of Chinese Luoyang bearing to wait. 2.

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The system of high speed feed with expensive precision of control of system of feed of 2 high speed also is one of crucial technologies that implement high speed cutting. System of traditional deputy transmission of ball guide screw shows inelasticity to system of high speed feed, must undertake to its the technology is improved innovate with the technology, ability gets used to the requirement of high speed cutting. Main technique measure has: (1) guide screw uses hollow structure, raise the bearing stiffness of guide screw. (2) be those who reduce system of deputy transmission of guide screw of high speed ball is calorific, connect cooling fluid interior of hollow guide screw to undertake enforcing circular cooling, in order to assure the precision of system of deputy transmission of ball guide screw. (3) improve nut structure design, reduce ball diameter appropriately, ball bearing uses hollow structure, the ball bearing in ball chain is pressed one big one small interval is arranged, can reduce the noise when high speed moves effectively. (4) improve ball data, ball chooses material of pottery and porcelain, can reduce temperature rise significantly. (5) use nut to rotate, plan of drive of guide screw immobile. Install nut in bearing, drive its to rotate by servo electric machinery, or make the rotor part of nut and drive electric machinery an organic whole, by rotor direct drive. This structure is secured as a result of guide screw do not move, axial shift is made while nut makes high speed rotate, reason can eliminate guide screw the limitation of critical rotate speed. The acceleration limits of system of deputy transmission of guide screw of high speed ball is (0.

5 ～ 1.

0) G, 6m of journey limits ≤ , use at machine tool of numerical control of cheap high speed; After system of high speed feed uses system of drive of feed of linear electric machinery, its acceleration can be as high as (2 ～ 10) G, journey limits is unlimited, use at machine tool of numerical control of high-grade high speed and high speed machining center. System of drive of feed of linear electric machinery has the following advantage: (1) high speed answers a gender. Because the system uses linear electric machinery direct drive workbench, the machine tool comes true " 0 drive " , reason makes trends of system of whole closed-loop control answers function to rise greatly, response is unusually acute and quick. (2) speed and acceleration are tall. Speed of the biggest feed can amount to 80 ～ 180m/min, acceleration can be as high as (2 ～ 10) G. (3) fixed position precision is tall. System of drive of feed of linear electric machinery often serves as the position to measure component with grating feet, use closed-loop control, consequently fixed position precision can be as high as 0.

～ of 1 μ M 0.

01 μ M. 2 the price of servo of linear electric machinery is servo of guide screw of high speed ball about.

5 times, but below the circumstance that is more than 1g in acceleration, former the only alternative that still is system of high speed feed. 2.

Technology of cutting tool of technology of cutting tool of cutting of 2 high speed is cutting of implementation high speed is important assure. Material of right choice cutting tool and system of design cutting tool machine quality to rising, lengthen cutting tool life and reduce finished cost to having main effect. 2.

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Cutting of high speed of material of cutting tool of cutting of 1 high speed asks cutting tool material has following property: Tall hardness, high strenth and wearability; Tall toughness, good heat-resisting pounds a gender; High fever rigid, good chemical stability. Current, high speed cutting machines commonly used cutting tool material to have: Cutting tool of coating cutting tool, pottery and porcelain (Al2O3, si3N4) , cubic nitrogen changes boron (CBN) diamond of material He Jujing (PCD) material. 2.

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1 coating cutting tool is current, the coating that uses at cutting tool of high speed cutting basically has two kinds: One kind is " hard " coating, wait for coating cutting tool like TiC, TiN and Al2O3, its advantage is hardness tall, wearability is good. Among them, tiC coating cutting tool has aspect of very strong the knife after fighting to wear away ability, tiN coating cutting tool provides those who have ideal to fight crescent moon depression function. One kind is " soft " coating, wait for coating cutting tool like MoS2, WS, this kind of cutting tool also is called " self-lubricating cutting tool " , cutting tool, workpiece and cut the attrition factor between bits very low, have about 0 only.

01, can drop cutting force and cutting temperature. Aerospace is industrial the treatment that material is like alloy of high strenth hard alloy, titanium to wait does not suit to use " hard " coating cutting tool; Use " soft " coating cutting tool, can prevent the generation on edge to accumulate bits tumour, raise workpiece surface to machine quality, prolong cutting tool life. 2.

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Cutting tool of pottery and porcelain of cutting tool of 2 pottery and porcelain is one of cutting tool stuff with high speed the most serious cutting. The cutting tool of pottery and porcelain that can be used at high speed cutting includes cermet (Cermet) , alumina pottery and porcelain (Al2O3) change silicon pottery and porcelain with nitrogen (Si3N4) etc. Cutting tool of pottery and porcelain has very tall hardness and wearability, comfortable at machining HRC50 ～ the tall hardness material of 65; High temperature capability is good, still can undertake cutting below the high temperature of 1200 ℃ ; Have fight felt function goodly, produce felt not easily with the metal, chemical stability is good. But cutting tool of pottery and porcelain fights function of difference of concussion load ability, heatproof concussion to differ, accordingly, when undertaking cutting with cutting tool of pottery and porcelain, fluid of unfavorable use cutting, comfortable do cutting at having high speed. 2.

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3 cubic nitrogen change boron (CBN) 　 cubic nitrogen changes boron (CBN) the hardness of material is next to diamond, be as high as HV3200 ～ 4000, have very tall wearability, thermal stability and chemical stability, the most comfortable quench at tall hardness steel of steel, high temperature alloy, sclerotic bearing (HRC60 ～ 62) , tool steel (HRC57 ～ 60) , high-speed steel (HRC62) the high speed cutting that waits for material. 2.

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4 get together brilliant diamond (PCD) 　 gets together brilliant diamond (PCD) 2 times what the hardness of material is CBN about, its thermal conductivity is good, hot coefficient of expansion attrition factor is small, minor, comfortable the high speed cutting at cupreous aluminium alloy, metalloid material and composite material, it is the main cutting tool that implementation high accuracy, efficient, tall stability and cutting of low surface surface roughness machine. The high speed cutting that PCD cutting tool basically uses at material of light metal and its alloy, new-style pottery and porcelain and difficult treatment material, use at the nicety, finish machining that exceeds nicety and optical component. 2.

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Parameter of geometry of cutting tool of system of cutting tool of cutting of 2 high speed has very big effect to machining quality and cutting tool durability, of cutting tool of cutting of general high speed before horn is made an appointment with than common cutting cutting tool small 10 ° , hind part is large 8 ° of 5 ° ～ . Cutting tool rotates in high speed when, can bear very great centrifugal power, its size exceeds cutting power far, become the main load of cutting tool, enough brings about cutter hub broken, cause grave accident. It is with high speed milling cutter exemple, the security technology that improves cutting tool design has: (1) high speed milling cutter uses HSK mostly hollow short awl knife handle and join of machine tool main shaft, sometimes construction of type of make it whole, locate in order to raise the repetition of tigidity and installation precision. (2) when high speed rotates, the lopsided meeting of cutting tool produces to main shaft system additional radial load, the square of its size and rotate speed becomes direct ratio. The whirl that goes up in high speed main shaft to installation for cutting tool, the dynamic balancing of high accuracy is crucial. Germany drafted 1994 " high speed rotates the security of milling cutter asks " standard regulation, the milling cutter that is used at high speed cutting must check through dynamic balancing. 2.

Craft of cutting of high speed of engineering technology of cutting of 3 high speed and groovy cutting craft have very big different. Groovy cutting thinks efficient come from low rotate speed, big cut feed of deep, delay, one-way Cheng; And high speed cutting is gone after high rotate speed, medium cut deep, speed to give, the treatment craft of much journey. When undertaking high speed cutting, workpiece material is different, craft of chooses cutting cutting tool, cutting and cutting parameter also have very big different. Research light metal, steel and engineering technology of cast-iron high speed cutting are emphasized below. 2.

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Aluminium alloy of technology of light metal of cutting of 1 high speed is able to bear or endure goodly because of having corrode sex, taller than intensity, conductivity and thermal conductivity are good wait for an advantage, had applied in great quantities in auto industry and aerospace industry. Aluminum-magnesium alloy uses cast mostly, the biggest advantage of these light alloy is his solid some cuts character easily. Light alloy can use very high cutting rate and feed speed to undertake machining, cutting speed can be as high as 1000m/min ～ 7500m/min, high speed cutting makes 95% ～ the heat in metal cutting of 98% is cut bits is taken away quickly, workpiece holds room temperature position, heat is out of shape small, treatment precision is tall. When light metal of high speed milling, because machine a process to be put in bigger concussion load, the life performance of PCD and CBN cutting tool is bad. When cutting speed achieves 1000m/min, can use cutting tool of K hard alloy; When cutting speed achieves 2000m/min, can use cermet cutting tool; When cutting when rate is higher, can use PCD cutting tool; When aluminum-magnesium alloy of high speed milling, can use cutting tool of K10 hard alloy. 2.

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Steel of cutting of 2 high speed and steel of milling of cast-iron technology high speed and cast-iron when, the main problem that encounter is cutting tool wear away. When rolled steel of high speed milling, cutting tool uses sharp cutting blade and bigger hind horn can reduce cutting tool to wear away, improve cutting tool service life. Of cutting tool wear away to be concerned with the mechanical function of workpiece material. If the tensile strength of workpiece material increases, criterion cutting tool wears away increase, because this should reduce the feed of every tine. Watch 1 gave out the cutting speed of steel and every tine feed. Normal Align=center> expresses 1 milling cutter reference of every tine feed is worth Normal TEXT-ALIGN of material of Center" Align=center> workpiece: Normal Align=center>fz/ : Normal Align=center> thick mill: Normal Align=center> essence: Normal Align=center> high-speed steel: Normal Align=center> hard alloy: Normal Align=center> high-speed steel: Normal Align=center> hard alloy: Normal Align=center> steel: Center" Align=center>0.

10 ～ 0.

15normal Align=center>0.

10 ～ 0.

25normal Align=center>0.

02 ～ 0.

05normal Align=center>0.

10 ～ 0.

15normal Align=center> cast-iron Normal Align=center>0.

12 ～ 0.

20normal Align=center>0.

15 ～ 0.

When milling of 30 　 high speed is cast-iron, the choice of cutting speed depends on cutting tool material. Raise cutting speed and reduce every tine feed, can raise workpiece surface to machine quality. Watch 2 gave out cast-iron cutting speed and every tine feed. Normal Align=center> expresses 2 milling to machine is worth Normal TEXT-ALIGN of material of Center" Align=center> workpiece: Center" Align=center> hardness (HBS) Normal Align=center>Vc/ (M.

Min-1) Normal TEXT-ALIGN of milling cutter of Center" Align=center> high-speed steel: Normal Align=center> hard alloy: Normal Align=center> steel: 225normal Align=center> ＜ : 42normal Align=center>18 ～ : 150normal Align=center>66 ～ : 325normal Align=center>225 ～ : 36normal Align=center>12 ～ : 120normal Align=center>54 ～ : 425normal Align=center>325 ～ : 21normal Align=center>6 ～ : 75normal Align=center>36 ～ : Center" Align=center> cast-iron Normal TEXT-ALIGN of Center" Align=center> ＜ : 36normal Align=center>21 ～ : 150normal Align=center>66 ～ : 260normal Align=center>190 ～ : 18normal Align=center>9 ～ : 90normal Align=center>45 ～ : 320normal Align=center>260 ～ : Center" Align=center>4.

5 ～ 10normal Align=center>21 ～ 　 3. The applied 　 of technology of high speed cutting 3.

Cutting of 1 high speed applies a lot of spare partses in aerospace industry mediumly to use structure of Bao Bi, fine muscle in aerospace industry, because stiffness is poor, not the deepness of penetration of a cutting tool with bigger be patient of, accordingly, high speed cutting becomes this kind of spare parts to machine the only alternative of craft. A few spare partses on the plane to rise dependability is mixed reduce cost, will primary reason many riveting or the part that solder and become, convert integral sincere material is made, this namely " whole makes a way " . The material purify rate of some integral component part is as high as 90% , use high speed cutting to be able to improve manufacturing efficiency and product quality greatly, reduce production cost, this also is the main reason that technology of high speed cutting wins wide application in aircraft manufacturing industry. For example, when Boeing company is producing Boeing F/15 battleplan, use " whole makes a way " , amount of aircraft spare parts decreased 42% , replace with high speed milling assemble a method to get component part of large Bao Bi, decreased to assemble wait for process. 3.

What the application of cutting of 2 high speed in automobile manufacturing industry is a foundation with high speed processing technique is nimble and flexible automatic product line is used by homes of more and more domestic and international automobile factory. Home amounts to a car like nimble of one steam masses automatic product line, by punch, solder, besmear outfit, general assembly, engine and drive implement wait for high speed product line to comprise, produce per year car ability 150 thousand, production metre 1150 / Min; Car of accept of tower of Shanghai masses mulberry is automatic product line. Abroad if the gives priority to with HVM800 horizontal machining center car product line that cooperation of Motor Corporation of flexible and automatic product line, Ford and company of Ingersoll machine tool develops the high speed of plant of assembly of American GM engine. 4. Technology of cutting of last word high speed has made the main trend that cutting machines, technology of high speed cutting to the technical revolution that a profundity is for mechanical manufacturing industry, be sure to produce important and far-reaching effect to mechanical manufacturing industry. The development of technology of high speed cutting and application are a complex systematic project, it involves cutting tool, machine tool, craft, material, nimble production, network, intelligence to change diagnose the technical development that waits for a lot of domain and innovation with breakdown. To get used to the product requirement that the market of rapid change and client change, high speed cutting and high speed processing technique are sure to producing craft disperse model and mix model enterprise (wait for production enterprise like mould, shipping, car and aerospace) in receive further progress and application. Structure of machine tool of cutting of prospective high speed will be had taller stiffness and fight brace up quality; As the development of machine tool technology, cutting tool technology and engineering technology, cutting tool life will longer, next makings on workpiece, measure and change the auxiliary time such as the knife will shorter. CNC Milling CNC Machining