Hard turning technology reachs his to apply

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Summary: The application of the condition that treatment of the characteristic that analysed hard turning treatment, hard turning requires and aborning of hard turning technology, crucial to its technology undertook discussing, pointing out hard turning technology is a kind of efficient, clean technique, have wide applied perspective. Turning treatment is a kind of the the the basiccest, most extensive, mainest technique in mechanical manufacturing industry, the efficiency that it affects production directly, cost, the sources of energy is used up and environmental protection. As a result of the development of modern science and technology, the project material of all sorts of high strenth, tall hardness is used increasingly, traditional turning technique is competent hard or cannot realize the treatment of material of pair of certain high strenth, tall hardness at all, and modern hard turning technology makes become a possibility, and aborning gains apparent benefit. The hard turning that the definition of hard turning of 1 hard turning and its characteristic says normally is the technique that the turning that points to a Cui hard steel regards final treatment or finish machining as, with avoiding the grinding technology that uses generally at present. Hard steel of temper by dipping in water points to to martensite organization is had after quenching normally, hardness is tall, intensity is high also, have the workpiece stuff of plasticity hardly. The hardness when hard steel of temper by dipping in water > when 55HRC, its intensity Sb is 2100 ～ 2600N/mm2 about. Normally, workpiece already completed rough machining process before heat treatment temper by dipping in water is hard, only finish machining undertakes below oil strong position. Essence of life is ground is the treatment craft with the most commonly used finish machining, but its size range of pipe bent narrow, investment efficiency of big, production is low, easy cause environmental pollution, the economy that perplexing hard steel of temper by dipping in water all the time is machined effectively. As the development of processing technique. Hard turning replaces grinding to already became a possibility, and aborning gains apparent benefit. Use nitrogen of much brilliant cubic metre to change boron at present (cutting tool of PCBN) cutting tool, pottery and porcelain or cutting tool of coating hard alloy right on lathe or turning machining center hard steel of temper by dipping in water (55 ～ 65HRC) undertakes cutting is machined, its machine precision to be able to amount to 5 ～ 10&micr0;m, mean effective value of exterior surface roughness is less than 20&micr0;m on average. The characteristic that good car engraves machines effect to lead tall hard turning to have taller than grinding treatment efficiency, and the 1/5 that the energy that its waste is common grinding treatment. Hard turning often uses big cutting deepness, high workpiece rotate speed, the 3 ～ that rate of its metal excision is grinding treatment normally 4 times. Clip of outfit when turning is machined is achievable a variety of surfaces are machined (the) such as the aperture inside the circle outside be like a car, car, recessing, and grinding needs for many times to install, accordingly, its assist time weak point, positional precision is tall between treatment surface. Hard turning is great majority of clean treatment craft below the circumstance, hard turning is beardless cooling fluid. In fact, use cooling fluid can bring adverse effect to cutting tool life and exterior quality. Because, hard turning forms cutting through making cut material anneal molten of the part, if cooling rate is exorbitant, with respect to this kind of effect that can reduce by cutting force generation, increase mechanical wear thereby, shorten cutting tool life. At the same time hard turning but the unit that leave out and cooling fluid concern, reduce manufacturing cost, simplify manufacturing system, form cut bits to do defecate clean, reclaim processing is easy. Installation cost is little, suit flexible when production asks to be the same as in productivity photograph, lathe invests the 1/3 ～ 1/2 that is grinder, fare of its support system is low also. To small lot production, hard turning does not need special device, and spare parts of high accuracy of big batch treatment needs to make fun of tigidity precision of good, fixed position and repeat the numerical control machine tool with fixed position tall precision. Lathe itself is a kind of size range of pipe bent wide flexible machine a method, turning outfit clip is fast, the ask treatment that uses the contemporary CNC lathe that deserves to have a variety of cutting tool dial or knife library to realize two kinds of different workpiece very easily is changed, hard turning suits this kind of treatment especially. Accordingly, compare with grinding photograph, hard turning can suit better flexible change manufacturing requirement. The major quantity of heat that hard turning can make the spare parts obtains good whole to machine the production in precision hard turning is cut bits is taken away, won't produce the exterior burn that machines like grinding and crackle, have good treatment surface quality, have accurate treatment circularity, can assure to machine the surface between taller positional precision. The cutting tool material of the conditional hard turning that 2 hard turning machine reachs his to choose cutting tool of hard alloy of coating of coating hard alloy is the Tu Fuyi on better in tenacity hard alloy cutting tool layer or multilayer the TiN with good wearability, TiCN, TiAlN and Al2O3, the ply of coating is 2 ～ 18µm, coating rises normally the following the action of two respects: On one hand, it is had so lower than cutting tool matrix and workpiece material that much heat conducts coefficient, abate the hot action of cutting tool matrix; On the other hand, it can improve the attrition of cutting process and conglutinate function effectively, reduce heat in metal cutting generate. Cutting tool of coating hard alloy and photograph of hard alloy cutting tool are compared, no matter be in,intensity, hardness and wearability respect all had very big rise. Be in to doing hardness the turning of the workpiece between HRC45 ～ 55HRC, the coating hard alloy of low cost can realize high speed turning. In recent years, a few manufacturer rely on to improve coating material and proportional method, also make the function of coating cutting tool has huge to rise. The razor blade that if a few manufacturer of the United States, Japan use patent of material of Swiss AlTiN coating and new coat,the technology produces, hardness is as high as 4900HV of 4500 ～ , when turning temperature is as high as 1600 ℃ of 1500 ℃ ～ hardness still is not reduced, do not oxidize, bit life is 4 times of general coating razor blade. And cost is 30% only, and adherent strength is good. It can be in 498.

Hardness of the treatment below the speed of 56m/min amounts to the mould steel of 47 ～ 52HRC. Cutting tool of pottery and porcelain of material of pottery and porcelain has tall hardness (91 ～ 95HRA) , high strenth (bending strength is good for 750 ～ 1000 MPa) , wearability, chemical stability is good, good fight felt function, coefficient of friction low and the characteristic with low price. When it is normal to use, durability is extremely tall, speed can raise 2 ～ than hard alloy 5 times, suit finish machining and treatment of tall hardness material, high speed treatment particularly, the hard steel of of all kinds temper by dipping in water that can process hardness to be 62HRC and sclerosis are cast-iron. Have alumina commonly usedly base pottery and porcelain, nitrogen changes He Jing of silicon radical pottery and porcelain, cermet to must add pottery and porcelain of pliable but strong. Carry much research in recent years, improve and use the new technology that make, the bending strength of material of pottery and porcelain and tenacity all had very big rise, the cermet razor blade that company coke develops Teweike completely tastes the new-style cermet NX2525 that like Japan company of metal of 3 water chestnut develops and Swedish hill newly CT series and series of coating cermet razor blade, the diameter that its grain organizes is petty to 1µm the following, bending strength and wearability all the cermet with common outclass, widened greatly the applied limits of material of pottery and porcelain. The nitrogen with Tsinghua university successful development changed cutting tool of material of silicon pottery and porcelain to also achieve international advanced level. The hardness of CBNCBN and wearability are next to diamond, have wonderful high temperature hardness, compare with photograph of cutting tool of pottery and porcelain, its hear resistance and chemical stability are a bit poor, but impact strength and it is better to fight broken function. It applies to hard steel of temper by dipping in water extensively (50HRC above) , pearlite casting pig, cold hard cast-iron the cutting treatment that waits with high temperature alloy, compare with photograph of hard alloy cutting tool, its cutting rate can raise an amount level even. The PCBN cutting tool with CBN high content, hardness good, compressive strength reachs tall, wearability high impulse withstand tenacity is good, its defect is thermal stability difference and chemical laziness are low, apply to heat-resisting alloy, cast-iron the cutting treatment that fastens agglomeration metal with iron. Content of grain of the CBN in compound PCBN cutting tool is inferior, use pottery and porcelain to make binder, its hardness is inferior, but the characteristic with difference of thermal stability of before was being made up for one kind of material, chemical low laziness, apply to the cutting treatment of hard steel of temper by dipping in water. In the applied domain of cutting casting pig and hard steel of temper by dipping in water, cutting tool of pottery and porcelain and CBN cutting tool can choose at the same time, because this undertakes cost effectiveness and treatment quality are analysed very necessary, in order to define which kind of material more economy. Graph face of the 1 knife after machining casting pig for Al2O3, Si3N4 and CBN cutting tool wears away VB circumstance, if plan institute is shown, al2O3 of excel of function of cutting of material of PCBN cutting tool, when be being machined with the dry type cutting of hard steel of Si3N4 temper by dipping in water, the cost of Al2O3 pottery and porcelain under PCBN material, cutting tool of pottery and porcelain has good thermochemistry stability, but however not as good as the tenacity of PCBN cutting tool and hardness. When the work that finishs with small feed circumstance below under 6OHRC in cutting hardness, cutting tool of pottery and porcelain is better choice. PCBN cutting tool agrees with circumstance of 60HRC of workpiece hardness prep above, it is more important to add man-hour to automation treatment and high accuracy especially. Besides, in identical hind wear out condition leaves knife area, the stress of workpiece surface remains after cutting of PCBN cutting tool also compares cutting tool of pottery and porcelain to be stabilized relatively, if pursue,2 are shown. Graph the relation of the VB when 1 cutting casting pig and cutting time pursues the leftover stress of 2 pottery and porcelain and hard steel of temper by dipping in water of cutting of PCBN cutting tool uses PCBN cutting tool to do hard steel of type cutting temper by dipping in water to still should follow the following principle: The condition allows to fall to choose to be cut greatly as far as possible in machine tool tigidity deep, the quantity of heat that such cutting areas generate makes metal of the area before blade local bate, can reduce PCBN cutting tool effectively wear away. In addition, in small PCBN cutting tool also should be used as far as possible when cutting visit, because of thermal conductivity of PcBN cutting tool is differred and making cutting area quantity of heat has not enough time to diffuse, cut an area to also can produce apparent metallic bate effect, reduce cutting blade wear away. What bit structure and geometrical ginseng teach affirmatory razor blade appearance and geometrical parameter is reasonable and affirmatory it is crucial to developing property of cutting tool cutting adequately. Press cutting tool intensity for, the intensity of point of a knife of all sorts of bit appearance from go to high low ordinal for: Lozenge of lozenge of lozenge of ° of circle, 1 00, square, 80 ° , triangle, 55 ° , 35 ° lozenge. After bit material make choice of, answer to choose the bit figure with tall intensity as far as possible. Hard turning razor blade also should choose as far as possible radius of big circular arc of point of a knife, with circle and rough machining of most diameter razor blade, the radius of point of a knife when finish machining is about 0.

8 ～ 1.

2µm. Hard steel of temper by dipping in water cuts bits to be red and soft forge banding, brittleness is big, yi She is broken, not felt, do not produce the tumor that accumulate bits in cutting surface commonly, the exterior quality of treatment is high, but power of cutting of hard steel of temper by dipping in water is greater, especially radial cutting force is compared advocate cutting power is even great, so cutting tool appropriate uses the part before losing (Go ≥ - 5 ° ) and bigger hind horn (15 ° of Ao=10 ° ～ ) , tool cutting edge angle depends on the machine tool is rigid, take 45 ° ～ commonly 60 ° , in order to reduce workpiece and cutting tool flutter. The hardness of choice workpiece material of cutting parameter is taller, its cutting speed should be jumped over small. The appropriate cutting speed of hard turning finish machining is 80 ～ 200m/min, commonly used limits is 10 ～ 150m/min, use cut greatly deep or intense intermittent result cut tall hardness material, cut fast should maintain in 80 ～ 100m/min. Usually, cut deeply 0.

1 ～ 0.

3mm. When demand of treatment surface surface roughness is high optional small cutting explore is spent, but cannot too small, want appropriate. Feed can choose normally 0.

05 ～ 0.

25mm/r, cease numerical value inspects exterior surface roughness to numerical value and productivity ask and be decided. It is Ra0 when exterior surface roughness.

3 ～ 0.

When 6µm, what hard turning compares grinding economy is much. Outside eliminating the cutting tool with logical choice to the requirement of machining complex, hard turning does not have special requirement to lathe or turning center, if lathe or turning center stiffness are enough, and the precision that a demand can receive when processing flexible work and exterior surface roughness, can use at the treatment of hard steel of temper by dipping in water. What operate to assure turning is smooth and successive, commonly used method is to use rigid clamp device and in cutting tool of the horn before waiting. Nevertheless people thinks generally, hard turning needs the lathe of tall tigidity, namely the key of hard turning is the machine tool has enough tigidity, at the same time compact eye has construction of plant of cutting tool, workpiece, clamp equal rigid. If workpiece uses his in cutting master piece,fixed position, bearing is mixed rotate can keep quite smooth, existing equipment can be used at hard turning. The uses course of hard turning technology 10 years development of technology of 3 hard turning reachs promotion application, achieved enormous economic benefits and social beneficial result. Technology of illustrate hard turning is in below the promotion application circumstance in the industry production such as roller treatment. Home of industry of treatment of make friends rod 10 large roller enterprise already used the home hard turning technology is right cold hard the of all kinds roller such as hard steel of cast-iron, temper by dipping in water undertakes the cutting such as barren car, thick car and fine vehicle is machined, all obtained favorable beneficial result. Raise treatment effect on average to lead 2 ～ 6 times, managing treatment man-hour and electric power 50% ～ 80% . If be in factory of roller of company of Wuhan iron and steel, when the thick car of cold hard cast-iron roll that is 60 ～ 80HS to hardness, half fine vehicle. Cutting rate rose 3 times, roller of every Che Yigen, managing electric power, man-hour is expended 400 multivariate, managing cutting tool expends nearly 100 yuan, obtained enormous economic benefits. Be like center of test of my school Electromechanical. With ～ of HRC58 of turning of FD22 cermet cutting tool when the roller of hard steel of 86CrMoV7 temper by dipping in water of 63 (V=60m/min, f=0.

2mm/r, ap=0.

Method of successive cutting roller amounts to 8mm) Chan Ren 15000m(VCmax=0.

2mm) , satisfied the requirement with fine vehicle acting grinding. Trade of industrial pump treatment is current the 70% ～ of manufacturer of pump of domestic Cha oar 80% already used hard turning technology. Cha oar pump applies extensively at the industry such as mine, electric power, it is the product that is badly in need of domestic and internationally, the Cr15Mo3 that its jacket, fender is 63 ～ 67HRC is tall hard cast-iron. The past because all sorts of cutting tool hard turning it. Be obliged to use the rough machining after anneal bate so, next again the craft that Cui fire machines. After using hard turning technology, solved sclerosis smoothly to machine a problem, absolved anneal to quench again two working procedure, managing a large number of man-hour and electric power. The car machines an industry to produce an industry in the big batch such as car, tractor the treatment difficult problem that hardware of temper by dipping in water often can encounter in industry of measure of medium crankshaft, camshaft and transmission shaft, knife and equipment maintenance. Be like our country plant of some engine car, need to undertake machining to bearing inner ring in equipment maintenance, bearing inner ring (the hardness of material Gcr15) is 60HRC, inner ring diameter is 285mm, use grinding technology, grinding surplus is inhomogenous, ability needing 2h has been ground; And use hard turning treatment, had machined an inner ring with 45min only. 4 last words pass old research and exploration, technology of our country hard turning obtained very great progress, but, the application of aborning of hard turning technology is not wide still. The reason basically has the following sides: (The effect understanding of 1) production company, handlers to hard turning is insufficient, think generally hard data can grinding; (2) thinks cutting tool cost is too high. The cutting tool cost with hard initial turning is higher than common hard alloy (if CBN comparing is common hard metal is precious 10 multiple) , but its apportion compares grinding in the cost on every spare parts low, day, brought result is close friends more than common hard alloy; (3) is insufficient to research of mechanism of hard turning treatment; (The standard that 4) hard turning machines can't coach production is carried out. Accordingly, besides undertaking to hard turning mechanism deep person studies, must strengthen what hard turning machines knowledge to groom, successful experience demonstrates to reach strict operation standard, make this kind of efficient, clean treatment method applies morely at production actual. Be in at present, if will hard turning and essence grind union to rise, the cost that machines flower of place of a general spare parts will compare grinder to finish rough machining and finish machining place to spend cost to reduce 40% ～ 60% . CNC Milling CNC Machining