Cutting tool breaks the case study with fluky bits and means of settlement

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Cutting tool breaks bits reliable, having major effect to normal production and handlers safety. In cutting treatment, collapse breaks the meeting that cut bits splatters person, grind easily caustic machine tool; And strip is banding the meeting that cut bits is twined go up in workpiece or cutting tool, easy scratch workpiece, cause cutting tool damaged, affect worker safety even. To numerical control machine tool (machining center) wait for automation to machine a machine tool, because amount of its cutting tool is more, tool carrier and cutting tool connection are close, the problem that break bits appears more significant, as long as among them, break the knife bits is fluky, destroy the automatic loop of the machine tool possibly, destroy whole transfer matic to run normally even, designing so, choose or when blade grinds cutting tool, must consider cutting tool to judge the reliability of bits. And to numerical control machine tool (machining center) wait, should satisfy following requirement: Cut bits to must not twine the tool in cutting tool, workpiece and its photograph adjacent, equipment to go up; Cut bits to must not splatter, in order to assure the safety of handlers and observer; When finish machining, cut bits cannot of cut workpiece already machined the surface, the influence already machined exterior quality; Assure the durability that cutting tool books, cannot wear away prematurely and do his utmost to prevent its damaged; When cutting bits to pour out of, the spray of fluid of not cloggy cutting; Cut bits won't slideway of cut machine tool or other part. On the foundation that satisfies afore-mentioned requirements, different cutting tool still has diverse demand to cutting bits length. For example the biggest length cutting bits that general thick Che Gang expects is controlled for 100mm; Fine vehicle should grow a bit. Should avoid too finely cut bits, a few significant position of slideway of because it is easy built-in machine tool and cutting tool device (be like datum plane) , need add guard not only so, return cleared the difficulty with cut bits to bring certain. To certain and not easy the cutting tool that breaks bits, if figuration lathe tool, grooving lathe tool is mixed,cut off lathe tool to wait, in numerical control machine tool (machining center) wait for automation machine tool to go up, should assure its stable bits. One, the classification of the appearance that cut bits is mixed according to parameter of geometry of workpiece material, cutting tool cutting dosage the particular case that wait, the appearance that cut bits has commonly: Banding bits, C form bits, collapse shape of drossy, pagoda coils shape of bits, clockwork spring coils bits, long close snail coils bits, snail coils bits (see a picture 1) . (L) is banding bits (1a seeing a picture) : When stuff of metal of plasticity of high speed cutting, if do not take bits step, form extremely easily banding bits, this form bits is continuous and ceaseless, regular meeting is twined go up in workpiece or cutting tool, the cutting blade of surface of easy cut workpiece or batter cutting tool, injure a person even, because this answers,avoid to form as far as possible banding bits. But also hope to get sometimes banding bits, cut bits in order to make can successful eduction. Be in for example on vertical boring machine when boring blind aperture. (2) C form bits (1 B seeing a picture) : When material of the carbolic steel with general turning, alloy steel, the lathe tool that if use,contains bits chamfer forms C form bits easily. C form bits was done not have banding the defect of bits. But majority of C form bits is collision break off in face of the knife after lathe tool or workpiece surface (see a picture 2) . The high-frequency that cut bits is touched and break off the smooth sex that can affect cutting process, affect the surface roughness that already machined the surface thereby. So, do not hope to get C form bit commonly when finish machining. And much hope gets snail coils length bits (3) seeing a picture, make cutting process smoother. (3) hair strip coils bits (1f seeing a picture) : Use on heavy-duty lathe cut steel of turning of deep, big feed greatly into, cut bits wide thick, if form C form bits to injure cutting blade easily, base injure a person to meeting flying collapse. Increase the radius of bottom land circular arc of the chamfer that break bits normally so, make cut bits to become clockwork spring state (4 seeing a picture) machining apparently collision breaks off, rely on its self-prossessed fall. (4) grow to coil closely bits (1e seeing a picture) : Grow to coil closely bits fashions a process smoother, clear convenient also, a kind of better bits look is on common lathe. (5) pagoda shape coils bits 〔 sees graph 1d) : When CNC machining, machine tool or transfer matic are machined, the hope gets this form bit, because such cutting,bits won't be twined go up in cutting tool and workpiece. And clear convenient also. (6) collapse is drossy (1c) seeing a picture: In turning when the brittleness material such as bronze of cast-iron, fragile brass, casting, form extremely easily acicular or the collapse of fractional shape is drossy, fly easily already the person that splash an injury, grind easily again caustic machine tool. If adopt a bits measure, can make cut bits to be connected short a shape. Anyhow, the specific requirement that cutting machines is different, the hope gets the appearance of bits also differs cutting, but no matter of what appearance cut bits, should break bits reliable. 2, in cutting the course of principle metal cutting that bits breaks off, cut bits to break off whether easily, be out of shape with what cut bits have direct connection, so research cuts bits to break off the principle must cut proceed with of bits metabolic rule from research. What form in cutting process cut bits, because passed bigger plasticity to be out of shape, its hardness will rise somewhat, and plasticity and tenacity are reduced significantly, this kind of phenomenon cries cold make sclerosis. After classics super-cooling makes sclerosis, cut bits to become hard and fragile, be handed in when it change when bend or pounding load break off easily. The plasticity that the place that cut bits endures is out of shape bigger, good fragile appearance is more prominent, it is easier also to break off. When the material of the high strenth that breaks bits hard in cutting, tall plasticity, tall tenacity, ought to try to increase those who cut bits to be out of shape, in order to reduce its plasticity and tenacity, facilitate the goal that achieves bit. Cut bits be out of shape can comprise by two parts: The first part is formed in cutting process, we say to be out of shape basically. With freedom of lathe tool of face of the knife before making the same score the place when cutting measures cut bits to be out of shape, more adjacent at basic metabolic numerical value. Affect basic metabolic the horn before main factor has cutting tool, negative pour speed of arris, cutting 3. Horn is jumped over before small, lose edge rate of wider, cutting is lower, cut bits be out of shape bigger, be helpful for breaking bits more. So, the horn before reducing, broaden loses edge, reduce cutting speed to be able to serve as the step that advances bits. The 2nd part is to cut what what bits is flowing and suffer in curly process to be out of shape, we say be out of shape to add. Because be below most circumstance, in only cutting process be out of shape basically still cannot make cut bits to break off, must increase to add again be out of shape, ability achieves sclerosis and the goal that break off. Force cut bits to endure the method with add the simplest metabolic, grind on advanced knife face namely piece (or suppress goes out) the chamfer breaking bits of proper form, force when cutting bits to flow into bits chamfer again curly be out of shape. Cut bits to endure additional again curly after be out of shape, farther sclerosis and fragile change, when it collision arrives workpiece or hind on knife face when, was broken off very easily. 3, the chamfer that break bits is opposite (roll) the influence of bits breaks bits chamfer to having add metabolic effect to cutting bits not only, and the appearance to cutting bits breaks off with what cut bits having main effect. In cutting treatment, the different figure that people uses bits chamfer namely, dimension and the chamfer that break bits and advocate the banking angle of cutting blade, those who will realize control to cut bits is curly with break off. To be known better and grasp these patterns, we are specific the form that analyses the chamfer that break bits, dimension and the chamfer that break bits and advocate the banking angle of cutting blade spends pair of appearance that cut bits and the influence that cut bits to break off. (one) , the form that decides the appearance of bits chamfer to break bits chamfer has linear circular arc model, linear model with complete circular arc model 3 kinds (graph of 5) seeing a picture is the appearance L of the 5 chamfer that break bits, linear the circular arc chamfer that break bits (5a seeing a picture) mix a paragraph to circular arc joins and be become point-blank by a paragraph. Make cutting tool partly point-blank before knife face, the size of Rn of radius of bottom land circular arc is right those who cut bits is curly and be out of shape have certain effect. Rn is small, cut bits curly radius is small, and cut bits to be out of shape big; Rn is big, cut bits curly radius is big, and cut bits to be out of shape small. (6 seeing a picture) . In medium cut fall greatly (cut 6mm) of deep Ap=2 ～ , general and optional Rn =(0.

4 ～ 0.

7) B, b is the width of bits chamfer. 2, linear model the chamfer that break bits (5b seeing a picture) intersect point-blank by two paragraphs and become, horn of its bottom land is 180 ° - σ (σ calls part of bits stage wedge) , bottom land horn (180 ° - σ ) the action that replaced circular arc Rn. Bottom land part is small, the curly radius that cuts bits is small, cut bits to be out of shape big; Bottom land part is large, the curly radius that cuts bits is big (see a picture 7) cut bits to be out of shape small. In medium cut fall greatly, horn of wedge of the stage that break bits chooses 60 ° ～ commonly 70 ° . Two kinds of afore-mentioned appearance break bits chamfer to apply to treatment carbon steel and alloy structure steel, general before horn is in γ . Inside 5-15 ° limits. The 3, complete circular arc chamfer that break bits (5c seeing a picture) γ of the horn before Rn of radius of circular arc of wide B of main parameter chamfer, bottom land is mixed. The relation between is: (when seeing graph 5C) wait for tall plasticity material when cutting red copper, stainless steel, often choose the complete circular arc chamfer that break bits. Because process tall plasticity data when, the horn before cutting tool is chosen more greatly (γ 0=25 ° - 30 ° ) likewise big before horn, the cutting blade that complete circular arc breaks bits chamfer cutting tool is solidder, groove is additionally more shallow also, facilitate shed bits, on purpose is more practical (8) seeing a picture (2) the width of the chamfer that break bits breaks Ap of deepness of B of bits chamfer width and feed F, cutting to concern, when feed F increases, cutting ply increases, break the width of bits chamfer to answer corresponding broaden; Cutting deepness is big, groove also answer proper broaden. Changeless, the change of B of width of the chamfer that break bits is curly to cutting bits affect with metabolic. Graph 9a is groove wide suit basically with feed, the classics that cut bits is curly the collision after be out of shape breaks off C form; Graph 9b is groove not quite wide, cut bits curly radius is small, be out of shape big, short C breaks off after collision form or form collapse broken flake; Graph 9c is groove too narrow, it is very difficult in groove to cut bits to squeeze Cheng Xiaojuan to jam flow, cause hold back bits to be met even batter cutting blade; Graph 9d, E is groove too wide, cut bits curly radius is too big, be out of shape insufficient. Break off not easily. Do not shed classics bottom land even sometimes and form freely banding bits. If use feed primary election to break the width of bits chamfer, say roughly, to cutting medium carbon steel, the relation of width B and feed F is B=10f about; And when cutting alloy steel, cut bits to be out of shape to increase, desirable B ＝ 7f. The width B of the chamfer that break bits also should suit with photograph of cutting deepness Ap. Choose groovy wide B roughly commonly according to Ap, when Ap is big, b also ought to somes big; And Ap is small, criterion B should be reduced appropriately. Because should be cut deep when big and groove is too narrow, cut bits wide, it is not easy in groove curly, such, cut bits often does not flow into bottom land and form by oneself banding bits; Should cut deep when small and groove is too wide, cut bits narrow, flow is freer, be out of shape not quite sufficient, break off not easily also. (3) the chamfer that break bits and advocate the banking angle of cutting blade breaks bits groove and advocate of cutting blade tilt the outside having inclined with commonly used means, parallel form, and inside inclined 3 kinds (the inclined outside 10) 1 seeing a picture sees a picture (10a) , outside the chamfer breaking bits of inclined, before wide hind narrow, before deep hind shallow. Inclined breaks bits chamfer outside cut bits curly be out of shape big, if the graph is shown 11 times, the cutting rate that A of round outside approaching work face manages is top and groove is narrow, cut bits most first suffocate suffocate and curly, and curly radius is small, be out of shape big; And be in in B of point of a knife, cutting rate is low and groove is wide, cut bits finally with bigger curly radius curly, this can produce a power, on face of the knife after making cut bits to retroflexion or work surface, via break off after collision and forming C form bits. The chamfer breaking bits of this kind of form. In medium cut deep when the range that break bits is wider, the effect that break bits is stable and reliable, the application in production is relatively wide. The numerical value of banking angle τ basically decides by workpiece material, when general cutting medium carbon steel, ° of =8 extraction τ - when alloy steel of 10 ° cutting, cut bits to be out of shape to increase, take τ =10 ° - 15 ° . But cutting greatly deep when, because stand by A of surface of the circle outside workpiece to be in (11 seeing a picture) width of the chamfer that break bits is too small, cut bits easy block, cut blade of bits batter cutting even, convert more commonly so parallel form. 2, parallel form (L0b) seeing a picture: Parallel form breaks bits chamfer cut bits to be out of shape the inclined outside be inferior to is big, cutting bits is to touch mostly machine in workpiece apparently break off. When the medium carbon steel that cut bits, the result breaking bits that parallel form breaks bits chamfer and outside inclined is basic similar, but feed should be increased slightly a few, what cut bits in order to increase is add and curly be out of shape. 3, inside inclined (10c seeing a picture) : Inclined breaks bits chamfer inside (12 seeing a picture) place of A of round outside workpiece face is the widest. And be in in B of point of a knife the narrowest. Cut bits to often be in in B so first curly Cheng Xiaojuan, and in A place criterion roll into coils greatly. When advocate the blade dip of cutting blade takes 3 ° - when 5 ° , cut bits to form successive length easily to tighten a bits. Inclined breaks bits inside groove and advocate the banking angle of cutting blade takes τ =8 ° commonly - 10 ° , inclined breaks bits chamfer form to grow to coil closely inside the cutting dosage of bits range is quite narrow, so its aborning uses the inclined outside be inferior to and parallel formula general, basically be to apply at fine vehicle or half fine vehicle. 4, a few kinds of commonly used methods that break bits (one) use bits chamfer: The place before be like is narrated, the chamfer that break bits has add metabolic effect to cutting bits not only. And what still can realize control to cut bits is curly with break off. The form that wants bits chamfer only, dimension and the chamfer that break bits and advocate the banking angle of cutting blade is appropriate, breaking bits is reliable. It is to solder no matter type cutting tool or cutting tool of machine clip type, it is to grind type cutting tool to still do not weigh the cutting tool that wear type to be able to be used again. For applicable and different cutting dosage limits. Hard alloy can squelch on dislocation razor blade the chamfer breaking bits that has a variety of appearance and different measure, facilitate choose, such already economy handy. This kind of method is the method that first selection answers in cutting treatment, also be the method with the widest application. Insufficient place is cutting tool reasonable geometry parameter is decided really, those who get bits asks is diversionary (2) use bit implement break bits implement have stationary and adjustable type two kinds. Graph the 13 adjustable type that go up for lathe tool break bits implement. Before lathe tool knife cover jacket blocks bits board 1, when be being poured out of before cutting tool of the edge that cut bits, because suffer,block bits board a block and the turn is broken zigzag. Break bits implement parameter Ln and α can be designed by need and adjust, be in in order to assure given below cutting condition, the stability that break bits is reliable. Loose bolt 3, in bedspring the action of 4 falls, can make block bits board 1 with pressing plate 2 raise together, facilitate block bits board to adjust the fast dislocation with bit and change. This kind breaks bits implement commonly used go up at the cutting tool of big, medium-sized machine tool. (3) , use bit unit to snap bit unit type a lot of, can divide commonly for mechanical, fluid pressure type and electric type, cost of the plant that break bits is high, but breaking bits is stable and reliable, use on transfer matic only commonly. Graph the sketch map of 14 the device that break bits that contain amputator to use those who go up at lathe tool. When turning, cut bits to pass guide bits passageway 2 pour out of, dish of form amputator that is rotated ceaselessly 3 cut off forcibly, after be being cut off cut bits to from platoon bits 6 eduction. Amputator is by transmission shaft 4 drive. In the graph 1 for lathe tool. (4) use in workpiece the apparently method that opens slot beforehand: Differ by workpiece diameter size, be being machined beforehand apparently edge workpiece axial leaves to give or count a groove, its deepness is less than cutting deepness slightly, those who make be cut cut bits to form weakness sectional, break off thereby. Such, assured to break bits reliably already, do not affect workpiece to already machined exterior surface roughness again. Although machine tenacity when older stuff, the effect that break bits is very good also. Be in for example the workpiece stuff with older tenacity of boring of essence of life (wait like 40Cr) when, when breaking bits very hard with other method, can be being machined apparently broaching gives fore-and-aft groove, undertake boring again. Use this kind of method to be able to show its distinct advantage. (5) parameter of geometry of change cutting tool and adjust cutting dosage by in front what narrate cut bits to break off the principle is knowable, reduce the role before cutting tool; Increase tool cutting edge angle; In advocate grind on cutting blade piece lose edge; Lower cutting rate; Increase feed and change advocate cutting blade appearance can make cut bits to break off. But, adopt these methods to break bits, regular meeting brings a few undesirable consequence, if productivity drops, force of aggravation of workpiece surface quality, cutting increases etc, this kind of method, use rarely on transfer matic, serve as the auxiliary method of bits only sometimes. In addition, use cutting fluid to be able to reduce the plasticity that cuts bits and tenacity, also be helpful for breaking bits. Raise force of cutting hydraulic pressure to be able to be made more cut bits to break off, in aperture treatment, use this kind of method sometimes. CNC Milling CNC Machining