Fast cutting machines the freeboard of titanium alloy

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Summary: On the foundation that elaborates element of processability of influence material cutting, use opposite cutting processability to analysed law analysis to induce the cutting processability of titanium alloy, farther the crucial factor that with respect to its difficult processability and cutting of influence titanium alloy machine undertook an analysis; Discussed freeboard fast cutting mechanism and treatment characteristic, emphasize what reach cutting tool with respect to limits of speed of the feasibility that exceeds alloy of titanium of high speed cutting, cutting to match etc had exploratory study. Alloy of 0 introductive titanium has proportion small, hot intensity tall, thermal stability and corrosion resistance are good wait for character, use extensively in aviation, spaceflight, nuclear energy and chemical industry. But this material cutting machines difficulty, all the time since the technical difficult problem that solves titanium alloy to machine effect to lead quality of low, surface to differ is being explored ceaselessly in, as advanced production technology more and more apply at manufacturing industry widely, the cutting treatment that exceeds technology of high speed cutting to apply at titanium alloy showed clear advantage. The cause that the main factor of the processability of cutting of material of influence of difficult cutting processability of 1 titanium alloy causes processability of cutting of difficult treatment material to differ commonly basically has the following to plant likelihood element: The particle with very tall hardness is contained in ① material. ② hardness or high temperature hardness are tall. ③ treatment sclerosis is big. ④ thermal conductivity is poor, cutting temperature is high. ⑤ data strength is great, especially high temperature strength is great. ⑥ is stuck easily with cutting tool receive. ⑦ chemical active is big. By treatment material the likelihood because afore-mentioned one plant or the influence of a few kinds of elements, cause its cutting processability to differ. Processability of titanium alloy cutting titanium alloy often uses the cutting below durability of particular cutting tool relative to processability of cutting of cutting processability material the cutting rate that place of some kind of stuff permits will measure. Take T=60min normally, criterion VT composes V60, if serve as the V60 when steel of carbon of cutting of hard alloy lathe tool fiducial, the ratio that the cutting rate that permits when cutting other material is V60 criterion V60 to be the same as V60 calls this material opposite cutting processability, titanium alloy sees a table relative to cutting processability 1. The horniness of intensity of element hardness high temperature that expresses 1 titanium alloy to affect cutting processability relative to cutting processability chooses treatment sclerosis sex and cutting tool processability of cutting of thermal conductivity of agglutinant chemistry affinity is opposite the 2112144 opposite rate that fix processability of cutting of each element aggravation press degree order is 1, 2, 3, 4. Processability of titanium alloy cutting is analysed by the watch 1 visible, because the chemical affinity of titanium alloy is great,causing the main reason with poor processability of titanium alloy cutting is reach thermal conductivity extreme difference: Big titanium alloy is in ① chemical affinity below high temperature of 300 ℃ above extremely easy with cutting tool material " kiss and " , a few elements in material of the cutting tool when cutting are not dissolve in titanium, it is have chemistry with titanium. ② thermal conductivity is poor, titanium alloy thermal conductivity is poor, emissivity is very small, cutting temperature is very high. The coefficient of thermal conductivity of titanium alloy is the half of industrial pure titanium on average, coefficient of thermal conductivity is the 1/5 ～ 1/7 of 45 steel, fall in identical cutting condition consequently, the cutting temperature of titanium alloy is 1 times higher than 45 steel above. Although force of cutting of ③ titanium alloy is not big, 75% what be carbolic steel about, but many the osculatory length of face of the knife before cutting bits and cutting tool is smaller than carbolic steel however, it is the half of carbolic steel about, thereby 1 when the stress that place of the point of a knife when cutting titanium alloy suffers is cutting carbon steel about.

5 times. ④ titanium alloy machines sclerotic phenomenon not very serious, make an appointment with and mild steel situation is same. The experiment proves, titanium alloy intensity heals big, its cutting processability is differred more; The content such as the aggrandizement element Al in alloy, Sn, Zr, Fe, Mo, Cr heals much, criterion alloy intensity heals tall, its cutting processability is differred more; The dissolve of generation gap solid such as oxygen of the impurity in titanium, nitrogen, carbon, hydrogen, make the capability of alloy aggrandizement stronger, the impact to cutting processability is consequently bigger also. Because affinity of titanium alloy chemistry is big,fast cutting machines the freeboard of 2 titanium alloy, thermal conductivity is poor and intensity is high, make cutting temperature rises considerably, cutting tool wears away aggravate, with conventional treatment the method is machined hard. Long-term since, the way that improves processability of titanium alloy cutting is all the time in exploration, logical choice is cutting tool material and parameter of cutting tool geometry, logical make cutting dosage, use proper cutting fluid to wait to all can be on different level the cutting processability that improves difficult treatment data. Heretofore had had a few methods, have commonly usedly use special heat treatment, heat cutting, introduce ultrasonic and vibration to wait to cutting area, but these methods are existing generally efficiency low, cost Gaojujia is versed in the malpractice such as card of quality one cannot say for sure. The advanced workmanship technology that what machine at titanium alloy aptly introduce to be able to improve manufacturing efficiency and treatment quality considerably here -- exceed high speed cutting to machine. Overspeed cutting characteristic and suitable scope exceed high speed cutting to machine is the breakthrough that knows to traditional cutting on cutting principle, as different as groovy cutting on cutting mechanism, exceed high speed cutting to have the characteristic of its oneself and suitable scope. Workpiece temperature rise is small reduce workpiece heat to be out of shape in exceeding high speed cutting, although the quantity of heat of generation is much, but the rate that because cut bits from workpiece,leaves is rapid, the heat in metal cutting of 90% above is cut bits is taken away, the quantity of heat that sends work is very small, workpiece accumulates quantity of heat few, consequently when cutting, the rise of workpiece temperature won't exceed 3 ℃ . Cutting force is small because cutting rate is high, make cut narrow of area of wind shear form, cut horn to increase, be out of shape coefficient is reduced and cut bits to pour out of speed fast, can make cutting is out of shape thereby reduce, cutting force is reduced lower than groovy cutting force 30% ～ 90% , cutting tool durability rises 70% , special agree with machine Bao Bi kind the workpiece of rigid difference. Its feed speed can follow quality of surface of tall treatment of material excision rate when cutting of lofty high speed of cutting speed rise to raise 5 ～ accordingly 10 times, such, the excision rate of the material inside unit time can rise 3 ～ 5 times. Additional, as cutting speed rise, it is OK to cut bits by cut very quickly from workpiece, reason remain is in apparently stress is very little, what nod temperature as a result of cutting is elevatory, the height that workpiece surface scale pricks can be reduced significantly, disappear completely even. Exceeding alloy of titanium of high speed cutting to exceed alloy of titanium of high speed cutting is to be below the action that rate of tall meet an emergency answers, improve its to machine function, get high treatment quality thereby. Ordinary control is in the rate that exceeds alloy of titanium of high speed cutting limits of 150 ～ 1000m/min. The crucial technology that exceeds alloy of titanium of high speed cutting besides cutting speed, still cutter spindle unit and feed unit make a lot of ingredient such as bearing of technology, machine tool and technology of test of auxiliary and unit production technology, treatment. The article basically exceeds alloy of titanium of high speed cutting be opposite in the process material focal point elaborates the influence huge cutting tool such as efficiency of cutting tool durability, treatment and treatment quality, in order to seek cutting tool and titanium alloy optimal match. The rate that because exceed high speed cutting,exceeds the cutting tool material of high speed cutting is higher than groovy cutting speed severalfold even ten times, cutting temperature is very high, because this exceeds high speed cutting,put forward higher demand to basically ask to cutting tool material. Cutting tool material should have sex of tall hear resistance, heatproof concussion, good high temperature mechanical function and high reliability. Use domestic and internationally at exceeding the cutting tool material of high speed cutting to basically have at present: Coating hard alloy, TiC(N) base cutting tool of hard alloy, pottery and porcelain, get together brilliant diamond PCD and cubic nitrogen change boron to wait. Cutting tool of coating of cutting tool of coating hard alloy is to be on the cutter hub with better tenacity, tu Lvyi layer or multilayer the difficult frit compound with good wearability, make cutting tool has tall tenacity to have very tall hardness and wearability again already, the life of coating cutting tool is compared not coating cutting tool wants tall 2 ～ 5 times. Get together brilliant diamond cutting tool is natural diamond cutting tool because nature is more fragile, the manage of easy edge crystal is creditable burst, bring about chunk collapse blade, already was gotten together below a lot of circumstances brilliant diamond (PCD) is replaced. PCD is join activator for raw material with black lead, become via agglomeration of high temperature high pressure, have very good thermal conductivity and wearability and tall hardness. Get together nitrogen of brilliant cubic metre changes boracic cutting tool to get together nitrogen of brilliant cubic metre changes boron (PCBN) is will imperceptible below high temperature high pressure cubic nitrogen changes boron (the much brilliant data that CBN) material passes combinative appearance agglomeration to be together, PCBN cutting tool has the advantage of CBN already, also relatively CBN is easy make, so PCBN got developing very quickly. PCBN has very tall thermal stability, can bear the cutting temperature of 1200 ℃ above, and have very tall hardness and very tall wearability. The titanium alloy requirement to cutting tool material the fabricating characteristics according to oneself of titanium alloy material, material of requirement cutting tool should be had fight change intensity tall, hardness tall, tenacity is good, hot rigid wearability is good, good reach medicinal powder hot sex is good wait for function. Divide afore-mentioned outside, because contain the cutting tool material of titanium to close very easily below high temperature in person with titanium alloy, can use the cutting tool data that combines titanium anything but so. Express what 2 exceed the cutting tool material with high speed commonly used cutting and titanium alloy to match PCBNTiC(N) of hard alloy of coating of PCD of cutting tool material base cutting tool of hard alloy pottery and porcelain matchs function actor admirable improper improper freeboard of alloy of fast cutting titanium and cutting tool material match to be opposite according to titanium alloy oneself of cutting tool material; Of a few kinds of when consider to discover cutting of high speed of appropriate Yu Chao commonly used cutting tool material and titanium alloy match a gender to exist very big difference, see a table 2. The function of PCD cutting tool is very appropriate at machining titanium alloy: The thermal conductivity with very good ① , because coefficient of thermal conductivity and emissivity are tall, heat in metal cutting comes loose easily piece, reason cutting temperature is low, 1 what the coefficient of thermal conductivity of diamond is hard alloy.

5 ～ 9 times. ② heats up coefficient of expansion inferiorly, the hot coefficient of expansion of diamond is smaller than hard alloy severalfold, it is the 1/10 of high-speed steel about. The hardness with extremely tall ③ and wearability, when diamond cutting tool is processing tall hardness data, the 10 ～ that durability is hard alloy cutting tool 100 times, be as high as hundreds of times even. 3 conclusion use freeboard alloy of titanium of material of fast cutting difficult treatment, solved the difficult problem of alloy of groovy cutting titanium, assured to machined quality to improve productivity substantially again already, have good progress perspective. The treatment that exceeds technology of high speed cutting to be used at difficult treatment material is maturing gradually, how to perfect the processing technique that exceeds alloy of titanium of high speed cutting further, it is the task that remains to study further. CNC Milling CNC Machining