About the research of technology of strong voice cutting

  • Time:
  • Click:448
  • source:AVELLINO CNC Machining
1.

Hard steel of foreword temper by dipping in water is the material of a kind of more difficult treatment, hardness is as high as 50 ~ 65HRC, basically include common quench steel, quench voice mould steel, bearing steel, roller steel reachs high-speed steel to wait. As a result of its typical wear-resisting structure, hard steel of temper by dipping in water is used extensively at creating all sorts of demands the fundamental component of tall hardness and tall wearability. As exceed material of strong cutting tool -- of pottery and porcelain and PCBN function raise the adjustment with the price, resolved the contradiction between workmanship of convention of hard part of temper by dipping in water and the market demand that expand quickly, make more hard steel of temper by dipping in water of treatment of economic ground cutting becomes a possibility. Strong voice cutting is to point to the treatment technology that uses the hard steel of temper by dipping in water that exceeds strong cutting tool to be more than 50HRC to hardness to undertake accurate cutting. Compare with grinding photograph, strong voice cutting has favorable treatment flexible, economy and environmental protection function, strong voice cutting is being used in foreword of grinding work of essence of life is the optimal choice that processes hard steel of temper by dipping in water. However, at present processing technique of strong voice cutting is used extensively not completely still by company place, its are main the use technology unfinished that the reason machines mechanism and cutting tool to strong voice cutting as a result of the enterprise not only understands completely and master, the element that because craft of strong voice cutting is a few mediumer,also does not stabilize at the same time restricted its promotion application. The article passes integrated domestic and international many document, cooling and the action of force of cutting of mechanism, strong to the feature of force of the cutting in process of strong voice cutting, formation that cuts bits voice and metallic bate effect, lubricant technology and already machined exterior quality to wait undertook discussion, with period the promotion application that promotes technology of strong voice cutting. 2.

The factor that feature of force of strong voice cutting affects force of strong voice cutting basically includes deepness of cutting speed, feed, cutting, hind knife face wear extent and workpiece hardness. The research of domestic and international scholar makes clear, when strong voice cutting is carried out on the machine tool of different accuracy class, cutting force does not produce change. The bearing of AISI52100 of cutting of PCBN cutting tool that Brazilian Dr. AbraoMendes chooses content of cutting tool of pottery and porcelain, low CBN and tall CBN content respectively steel (the discovery when hardness 62HRC) : Radial cutting power is the greatest, it is next advocate cutting force and axial cutting force; The 6 ~ when force of the cutting when rough machining is finish machining about 9 times; Wear extent of face of the knife after deepness of cutting force and feed, cutting is mixed concerns into approximate linear; When cutting rate increases, cutting force has a bit drop. W of university of industry of German A go smoothly. Professor Konig is passed with cutting tool of pottery and porcelain and 100Cr6 of cutting of PCBN cutting tool the cutting force of steel of hard bearing of temper by dipping in water contrasts experiment, studied deepness of cutting speed, cutting and feed are right the effect tendency of cutting force. Consider to make clear: Advocate the change of cutting force and axial force and cut show linear greatly to increase a current, and radial load growth is slow; Different feed affects a trend to agree to the change of cutting force, the growth rate of axial force a bit under advocate cutting force and radial load, and when feed very hour, meeting occurrence radial load is more than advocate the phenomenon of cutting force. One hero teachs Japanese Zhongshan think, increasing the main reason that cutting speed makes cutting force drops somewhat is cutting temperature lifts make workpiece plasticity increases (namely metallic hardness reduces) because of the action of cutting temperature. Nevertheless the change of this kind of property is confined to certain cutting speed limits, when cutting speed exceeds 20Om/min, cutting force not the edge drops the passageway changes. This and W.

The research that Konig teachs agrees as a result. One hero teachs Zhongshan think, although temper by dipping in water is hard the hardness of material is taller, but cutting force is lesser, its reason is as a result of what rupture generation makes plasticity is out of shape very small, 2 because one bits interface accumulates the knife,be small, make attrition force is reduced. Professor of tribute of Liu of college of Harbin grain industry uses orthogonality to experiment to undertake designing to each influencing factor of cutting force, reached the three-dimensional curved surface of force of cutting of deepness of cutting speed, cutting, feed and workpiece hardness correspondence, reached below experiment condition advocate the conclusion that rule of cutting force change accords with theory of traditional metal cutting basically. E of British Birmingham university.

G.

Dr. Ng is right the cutting temperature when hard steel of temper by dipping in water of AISIHI3 of cutting of PCBN cutting tool and cutting force undertook finite yuan emulate seek solution, its are the biggest the error amounts to 25 % , precision is dispersive the gender is big. Be restricted from time to tome together yuan of computation amount is very large also. Zhang Hong Professor uses extruding and rolling theory, undertook be elaboratinged deep to pouring the cutting mechanism of arris cutting tool according to energy principle, the 3 divisions model that offerred cutting tool pouring arris (the first be out of shape dead band of area, metal, the 2nd be out of shape area) , can undertake forecast and be emulationed to cutting horn and cutting force; Be analysed according to metallographic and fall quickly knife device, hair cash belongs to the existence of dead band and do not rely on cutting speed, before horn and angle pouring arris; Below similar cutting requirement, of cutting tool pouring arris cut horn to be less than only pointed cutting tool to cut horn to make an appointment with 2 ° ~ 3 ° . Taiwan scholar K.

Fuh used principle of the smallest energy to amend the cutting model that Jing Ying of joint of bones orders, according to active force of area of the knife after cutting area and consideration, undertake emulation to cutting force, its are integrated precision is taller. As a result of the experience coefficient that introduce more, to different cutting tool and workpiece material these coefficient often are change, because this uses a sex actually,be restricted certainly. 3. The stress that the process of cutting of metal of the shape that cut bits of strong voice cutting studies and core are the formation that cuts bits process. Process of strong voice cutting arises commonly zigzag cut bits. K.

F.

Dr. Koch and P.

Dr. Fallbochmer thinks, the cuts bits configuration to suffer the ply that cut bits impact of strong voice cutting is the biggest, easy generation is banding when should cutting bits ply to be less than 20 μ M cut bits, generate otherwise zigzag cut bits. Form zigzag the account that cuts bits basically is the workpiece material near face of the knife before cutting tool be squashed and pile up on advanced knife face, cutting tool continues forward cutting causes the material that cut bits to happen to rupture suddenly. About zigzag cut bits to form mechanism to have a lot of famous judgment. The mutation when Recht put forward cutting to machine 1964 is cut break firm classical model, when nominal stress slope of curve of one true meet an emergency is zero hour, when the front of the sclerosis of meet an emergency that the local rate that temperature changes is equal to to the negative effect of intensity or is more than intensity place generation namely is affected, the plasticity of material interior is out of shape the area produces choppy clipping. The HouZhen-Bin that American Oklahoma establishs an university and RangaKo Ⅱ 1and put forward zigzag the thermodynamic model in cutting bits to fashion a process, their experiment makes clear, cutting speed and feed are in cut happen break firm in having main effect. Samiatin and the bate of going from place to place that Rab discovers it is normal to become lead corresponding gearshift to lead sensitive value than be equal to or be more than 5 when, the blame of metallic cutting process flows to happen immediately equably. Thermoplastic the instability of the process (sclerosis of meet an emergency and hot bate) bring about clipping area to arise, although do not have hot bate effect, other mechanism also can make cut take shear strength to be reduced apparently. Should cut for example when taking generation micro-crack, make bear the actual area of stress is reduced, walker and Shaw think this is bits cuts to rupture in machine treatment a kind likelihood mechanism. Shaw and Vyas are right recently inferior cut fast the research that next treatment AISI4340 steel and alloy of titanium of low speed treatment produce division account to cut bits more confirmed afore-mentioned notions clearly. Because right now cutting rate is very low, the heat that cuts generation can diffuse to aleatoric flank, hot bate is quite difficult, because this can explain,to make as a result of the existence of micro-crack actual clipping intensity is reduced. Clipping breaks firm other mechanism to include material to organize change, if be in certain steel,martensite changes to the changeover of austenite. One hero is opposite Zhongshan when turning of strong voice of hard steel of temper by dipping in water zigzag the viewpoint that cuts bits to form mechanism is: Cut bits to form traceable freedom apparently cut meet an emergency to be worth the largest part. Of adjacent and free surface be out of shape hypothesis pure the result that cuts action, cut rupture to be 45 ° with free surface included angle. Sih is obtained with analytic law " meet an emergency can density " factor S, drafted in lower mould of condition of planar meet an emergency zigzag those who cut bits create mechanism, when putting forward hard steel of temper by dipping in water of strong voice cutting zigzag the new model that cuts bits to form, gave out laden horn φ and rupture horny θ the 0 relation between. The research that Wang Minjie of college of Dalian grain industry, Hu Rongsheng teachs makes clear, zigzag cutting bits basically is what arise because of high speed cutting is thermoplastic cut break firm be caused by. Thermoplastic cut break firm it is extensive consist in a lot of dynamic plasticity are out of shape a kind of material in the process destroys a phenomenon, its precondition is the enough of hot bate effect that is out of shape the local temperature rise of material is caused of quits material be out of shape aggrandizement effect. In metallic cutting process thermoplastic cut break firm it is to point to happen in the first be out of shape of the area intense and local cut concentration, what its bring about asymmetry as a result is zigzag cut bits, what it and common metal stuff form below low speed is crowded crack cut bits to differ, the feature is those who cut bits each are toothed between in order to be out of shape very big thermoplastic cut take be apart. Use SNMG120412N of cermet razor blade, the test result of steel of bearing of GCrl5 of cutting of UG(brand ZKOI) makes clear: It is when cutting deepness 0.

5 ~ 4mm, feed 0.

07 ~ 0.

130 ~ of ≥ of speed of 43mm / R, cutting when 160m/min, begin to produce heat build-up model to cut break firm. 4.

Arise and conduct of the in already machining exterior integrality cutting to machine a process heat in metal cutting of strong voice cutting, high speed chafes and wear away wait for an element the metropolis is certain to already machining the surface to cause of degree destroy. The key that replaces grinding treatment with strong voice cutting is condition of precision of the treatment surface surface roughness that how obtains ideal, appearance and treatment surface, and the function of the treatment precision that raises strong voice cutting and workpiece of strong voice cutting is a need long-term the task that deep person studies. Strong voice cutting already machined exterior integrality to basically include the following content: Of precision of surface roughness of configuration of surface layer organization and its hardness, surface, dimension, leftover stress distributing and the generation of white layer. American general crosses university C.

R.

Professor Liu is in early published 1976 cut bits to form a process to be opposite already machined the surface inferior surface layer is mechanical the paper of condition, basically analysed pointed blade cutting tool and wear away the cutting tool influence to leftover stress. The closest C.

R.

Liu still proved the feasibility that exceeds steel of hard bearing of temper by dipping in water of cutting of nicety strong voice and cutting condition through the experiment. Be in the leftover stress model that exceeds cutting of nicety strong voice to machine the surface, imitate and optimized research respect to do a large number of works. The research work of German PLeskovar makes clear: Already machined the surface the effect that microcosmic hardness suffers wear extent of face of the knife after feed is mixed is bigger, feed is smaller, wear extent is bigger, exterior hardness is taller. The cutting of orthogonal strong voice that Liu Xianli teachs experiments to make clear as a result: Cutting speed, feed and cutting deepness have onefold change law to the influence of exterior hardness. Already machined exterior hardness to rise and increase of speed along with cutting namely. Mix along with feed cut deep accretion and reduce. And already machined exterior hardness taller, sclerotic layer deepness is bigger. The matrix that passes pair of test specimen is organized and the photograph of scanning report lens of surface layer organization undertakes contrasting analytic, think to although rise somewhat,exterior hardness already was machined in process of strong voice cutting, produce certain sclerotic deepness, but destroy to the metallographic of exterior surface layer is organized and be not being had. Birmingham university D.

K.

Professor Aspinwsll uses the discovery when steel of bearing of hard AISIE521O0 of pottery and porcelain and temper by dipping in water of cutting of PCBN cutting tool on lathe of tall rigid numerical control: Workpiece surface layer and inferior the constituent position of surface layer produces change, its are microcosmic organization by white not of temper layer and black cross temper layer composition. Surface of the workpiece after experimental result shows strong voice cutting all presses stress for remains, and of the workpiece after grinding the biggest press stress to basically be centered in workpiece surface. The composition of leftover stress and material, organization and defect are same. Have very big effect to the mechanical function of workpiece, the bulk that leftover stress must control below most circumstance reachs his to distributing the rule. Material of the geometrical appearance of blade of the floating rate that the generation of leftover stress in process of strong voice cutting is thought to reach heat source with the formation of heat in metal cutting, cutting, workpiece and cutting tool wear away etc the relationship is close. The generating that many foreign scholars try to pass emulation heat in metal cutting and shift will calculate leftover stress, but the complexity that heat in metal cutting forms and leftover stress measure the reason such as the error to cause emulation error bigger. Recently, canadian KurtJacobus applies planar meet an emergency to stick play general of plasticity theory, United States to cross university S.

Mittal applies multinomial to plan to add up to a principle to calculate the impact that cutting parameter distributings to leftover stress, its insufficient place is to need to undertake much demarcate experimentation will estimate coefficient. J.

D.

The influence of the appearance of geometry of blade of the cutting in studying process of cutting of nicety strong voice such as Thiele and workpiece hardness to stress of workpiece surface remains, pointed blade is chosen respectively in the experiment, pour arris, blunt circle the PCBN cutting tool of ministry of 3 kinds of blade, the test shows as a result: Radius of cutting tool blunt circle is bigger, value of remains pressing stress is greater; Workpiece hardness is taller, value of remains pressing stress is greater. Y.

Matsumoto and D.

W.

Wu also thinks workpiece hardness is great to the influence of workpiece surface integrality, workpiece hardness value is greater, be helpful for remains pressing the formation of stress more. Y.

Matsumoto still thinks, appearance of cutting tool geometry also affects the formation of leftover stress, double the remains that pours arris and place of big blunt round cutting tool to form presses stress far excel is onefold pour arris and pointed blade cutting tool, but cutting parameter (cut mix greatly feed) did not affect significantly to leftover stress. Affecting strong voice cutting to already machined another of exterior quality main factor is the formation of white layer. White layer is the configuration of a kind of organization that accompanying place of process of strong voice cutting to form, it has wear away distinctly characteristic: On one hand hardness is tall, be able to bear or endure corrode sex is good; Show taller brittleness again on the other hand, easy cause inchoate flake invalidation. White layer size is smaller, be hard to accurate analysis its organize a feature, its formation mechanism up to now still open to question. A kind of viewpoint thinks white layer is the result that changes, it is the grain that be heated quickly in cutting process by material and cool abruptly and forms petty fine brilliant martensite is comprised. Another kind of viewpoint thinks the formation of white layer is belonged to only be out of shape mechanism, just be not convention martensite by what plasticity is out of shape and get. The point of view that regards white layer as martensite the organization at present gets accord admissive, main dispute depends on the elaborate structure of white layer. Y.

K.

Chou and C.

J.

Evans thinks the formation of white layer in process of strong voice cutting and heat in metal cutting are concerned, hind the addition of knife face wear extent will bring about white layer deepness to increase, achieve in VB 0.

White layer deepness is as high as LO μ M when 31mm. B. J. Griffiths thinks to the account from layer phenomenon produces in cutting process is high speed slides wear away, the constituent configuration of white layer is the mixture organization of the austenite that exceeds fine grain structure and martensite, wear away with cutting tool closely related. Accordingly, need is farther deep the formation of 8 research white layer mechanism reachs his to be opposite the influence of spare parts life. 5.

At present processing technique of strong voice cutting already caused the development tendency of technology of strong voice cutting worldwide inside the height of manufacturing industry bound and scientific research orgnaization takes seriously and great interest, but processing technique of cutting of promotion application strong voice still is put in certain obstacle, main problem has: How to make already machined the surface to maintain stable exterior surface roughness and dimension precision; Already machined exterior quality whether the operating mode of contented spare parts needs and have certain life; The choice that how undertakes strong voice cutting machines cutting tool, use, cost control. Accordingly, the research of mechanism of treatment of cutting of prospective strong voice and its technology is mainly: The size of force of the cutting in controlling cutting process maintains its stability; Eliminate and reduce heat in metal cutting to be opposite the action of work measure precision; The rationalize of cooling and lubricant technology in process of strong voice cutting; Of the gradient that already machined exterior hardness, leftover stress distributing, the research that surface layer organizes configuration and white layer to form mechanism. CNC Milling