Basic model group when be being gotten in drill through to expect with structural steel products, acquired good cutting property. But process data increasingly diversification, the processability differ in thousands ways of of all kinds material, condition of the structural form that processes a spare parts, craft also is having very big change. Workpiece stuff went, the demand of aperture went, make auger model also must change accordingly, want to have flexibility. Should be analysed correctly and estimate external state of affairs, take significant step. This chapter will emphasize analysis and the bore experience that sum up all sorts of circumstances to fall and preliminary rule. The problem that encounters in the problem bore of the generation in the first bore is very much, below from treatment material and craft condition two respects list some of example, the place when the specification uses drill of common twist drill reveals exposed problem. One, the problem that different place produces treatment material (1) gets intensity when the steel products with big, high hardness (like all sorts of high strenth alloy steel, quench the) such as steel, negative charge is big, auger do not move, reluctance getting goes down, broach is ground very quickly blunt, burned-out. (When 2) gets tall manganese steel and austenite stainless steel, produce serious treatment sclerosis phenomenon, get harder more, broach wears away very fast, generation burr is very serious. (3) gets steel on drilling machine when (like) of mild steel, stainless steel, cut bits to grow and ceaseless, circle like as long as two snake and go out, twine go up in main shaft, throw a person in disorder, very insecure, and cutting fluid is added do not go in. Go up in automatic machine bed this one issue is more outstanding. (When 4) getting is cast-iron, cut bits to become broken end, like abrasive, high speed cutting is constant broach two outside predestined relationship corner wears away. (Form of the aperture when 5) digs red copper constant out of round, get soft red copper to break bits not easily also, sometimes broach is bitten to be inside aperture. (The material such as 6) getting brass often arises " plunge into a knife " phenomenon, play hole gently, make again broach twist off. (7) gets aluminium alloy hole wall not only, cut bits not easy eduction, cut bits to often be squeezed dead when drilling deep hole especially getting channel in. (8) getting lamination is plastic (if place cloth bakelite, clip,paper bakelite, spun glass places the) such as cloth bakelite, produce aperture entrance to be in hairiness constantly thorn, the statified, surface intermediate becomes angry phenomenon of desquamate of a Huang Bian, exit. (When 9) gets organic glass, aperture is not shining, hair is dark (black) , it is fully bright and clean originally bright, after drilling hole, hole wall becomes ivory, more serious when hole wall burn, with generation " silver-colored spot " shape crackle. (When 10) gets rubber, aperture systole amount is very large, yi Cheng taper, go up big small, hole wall is coarse. 2, craft condition is different the problem of generation (1) drills laminose hole, sometimes workpiece does not facilitate impaction, people uses a hand to help up more, but when broach just should get a work, the hand does not help work, happen shake, give inductrial injury accident very easily. Additional, kong Yi arises polygonal, burr and be out of shape. (2) gets deep Kong Shi, cut bits difficult eduction, often want halfway for many times to exit broach ability to drill one hole, people says for " woodpecker type " auger cut way; Drill the hole with large diameter (the aperture) that if the diameter is gotten on steel,is more than 35 millimeter, it is more difficult to be gotten with common twist drill directly, negative charge is big, broach and machine tool do not bear, often happen " frowsty car " , want to get an alveolus first right now, reaming of reoccupy old bit. If, extortionary get, feed is sure choose very smally, such manufacturing efficiency are very low. (When 3) already should have reaming of semifinished product Kong Zai on workpiece, because mental allowance is inhomogenous, the surface is crusty, broach regular meeting is accordingly askew, point molders easily also. (4) is in tilt when the bore on the surface or curved surface, broach often does not stay in a center surely, happen deflective, often must make the same score workpiece surface Huo first, next ability bore. (5) needs as a result of what grain produces, to save nonstandard the special reamer of dimension, the hope gives opening of essence of life with broach getting. This also is the difficult problem that we often encounter. (6) grain production is used when underlining bore, broach searchs not easily, when aperture nest delimits shallowly, aperture slants to discover not easily; Delimit deep when, see aperture slants to search again laborious also. (7) undertakes reaming with broach, easy also generation " plunge into a knife " ; Sometimes hole wall appears great spire channel, after using opening of reamer bore with a reamer even, also cannot get rid of. (8) pours wine cup with broach Huo, incidental shake, appear polygonal, or the burr with serious generation. Of material of the 2nd workpiece get cut processability one, in summarizing the contradictory unity in broach and workpiece, generally speaking, broach is contradictory main field, but often also can happen change. Because this studies bore process, want to study cutting tool one party already, the other one party that should study contradiction again -- workpiece material. Here, emphasizing those who need research is workpiece material auger cut processability. Of workpiece material auger cut processability (or say to be able to be gotten cut a gender) it is to show material cuts a course through getting by semifinished product, it is difficult to get a requirement aperture look the craft of easy degree is characteristic. Apparent, get cutting processability is an omnibus index. As a result of,this is all sorts of problems in bore: Quality of force of manufacturing efficiency, cutting, durability, treatment interweave to be together integratedly, cut bits to be out of shape with attrition motion decides move getting cuts force and heat in metal cutting; Get the effect that cut heat move getting cuts temperature and cold hard layer; And the tumour that accumulate bits and auger cut temperature closely related; The tumour that accumulate bits, vibration is squeezed with what cut bits blow a limitation to wear the surface is bright and clean spend rise; Aperture asks to jump over essence of life to jump over light, limitting broach durability and manufacturing efficiency again rise, ... . Still should point out, because all sorts of material are in,the specific requirement in bore differs, its get the quota that cuts processability to also differ. The factor that affects material getting to cut processability is very much, physical do one's best learns function, chemical composition, material to make wait with heat treatment method. If metallographic is organized,chemical composition and material create position is the basis that decides physical do one's best learns function, act well directly however still be physical do one's best however learn function, it includes intensity (or hardness) , plasticity (or tenacity) , heat conduction rate and linear expansion coefficient and stretch coefficient, these elements affect the discretion of bore efficiency directly. 2, auger cut processability to classification of index data auger cut processability, can use a kind of classificationed method to undertake deciding roughly. Learn the size of function index by main physics do one's best namely, cent becomes 11 form, if express 5 ― 1. Bore is aimed at in the watch (use drill of high-speed steel twist drill especially) characteristic, the hardness HB(of material of make choice of or intensity σ B) , percentage elongation σ (or K) of concussion value α , coefficient of thermal conductivity 9 with stretch coefficient 4 (or Ⅸ of linear expansion coefficient) the quota that cuts processability as assess getting. When stuff kind certain (be like steel, cast-iron or copper alloy) when, hardness heals tall, criterion intensity heals big, have certain and corresponding concern, it is hardness no matter be being returned high is intensity big, can make cutting negative charge big, accordingly, usable hardness or intensity limit or both medium high order and degree regards assess as one of index. Need to point out additionally, machine σ B=100 with hard alloy lathe tool kilogram the rolled steel of 2 belongs to force ／ millimeter the grade of easier cutting, and should convert when high-speed steel twist drill is gotten, should belong to get cut order and degree harder. Same, when material type is certain, its plasticity percentage elongation σ and tenacity (K) of concussion value α mutual also have particular concern. Normally, when percentage elongation σ is big, k of concussion value α is tall also. Both although have,differ on physical meaning: The plasticity deformation that plasticity token material can allow; Tenacity represents material can susceptive blow energy (like cutting power) , but they are affected approximately auger cut a course. σ or α K value heal big, it is difficult to cut bits to heal break off, cutting bear (auger cut force and auger cut power to use up) more big. Accordingly, usable σ or α K or both medium high order and degree regards assess as one of index. Returning what should notice is, get the Ⅱ that cuts processability index, with medium plasticity (or tenacity) processability had better. Plasticity (or tenacity) too low, exorbitant, can get cut a gender all addle. When material brittleness is very big, cut bits collapse to break break even pulverous, to the platoon bits is mixed medicinal powder hot all adverse, cutting force and heat will be centered on point, bring about durability to reduce. Stretch coefficient E and α of linear expansion coefficient, to aperture treatment, often have bigger effect, the flexibility of bore diameter replies and heat up for example bilge cold shrink, the attrition that affects hole wall and broach directly, wear away to be measured with bore diameter dilate. Same, also use E or α or both medium high order and degree regards the 4th assess as index. By go up visible, when index of these 4 assess is expressing to get the contradictory characteristic that cuts a course, each have emphasize particularly on, namely: Ⅰ -- bear, Ⅱ -- cut bits (break bits, stick knife and case hardening) , Ⅲ -- temperature, Ⅳ -- change (contractive) . 3, of commonly used material can get cut a gender to classification the of all kinds material that often encounters in bore, include steel of cast-iron, carbon, alloy steel, stainless steel, nonferrous metal, metalloid material to wait, its are main physical ― mechanical function and can get cut a gender to classification rank watch 5-2, 5-3. Every kinds of material can get the code name that cuts a gender to classification to express to be: Before above two (1) , (2) can get each quota that cuts a gender to classification to all do not exceed 5, accordingly its can be gotten cutting a gender is good or better. By (3) exemple is knowable, 45 steel classics quenchs and in after lukewarm temper, hardness, intensity soars, cutting force adds, can get the addle that cut a gender. And (4) exemple, stainless steel 1Cr18Ni9Ti, although intensity does not calculate tall, but because of its plasticity is mixed greatly coefficient of thermal conductivity is low, cause cut bits to be broken not easily, treatment is sclerotic and intense, the heat in metal cutting of generation much, temperature is high. Accordingly, when bore, answer to be treated seriously as main problem, take the way to deal with a situation. The 3rd section getting is cast-iron one, of the problem like putting forward casting pig and carbon steel, also be a kind of iron (Fe) and carbon (the alloy of C) , the prep above that contain carbon of 2 ％ it is cast-iron. Cast-iron it is one of data with machinist job extensive application, for example machine tool lathe bed, machine base, all sorts of casing, housing is cast-iron (make like HT15-33, HT20-40) , a lot of machine tool factories, assorted drilling machine uses on the product line of car, tractor plant many axis to get this kind of data mostly. Nodular cast iron passes mould forward molten iron joins a ball to change agent and graphitizer, show crystallization of bulbiform black lead in order to make carbon, its intensity and plasticity all compare casting pig tall. Getting cast-iron Kong Shi with common twist drill, discovery has undermentioned characteristic: (Of 1) broach wear away to go up almost completely at the back, office of predestined relationship corner wears away outside the biggest, sometimes whole horn is ground, restricted those who manufacture efficiency to rise. (2) is repaired when horizontal blade when be being ground too narrowly, broach dies easily blade or collapse needle, get especially cast quality to differ or contain the workpiece that casts black skin. (3) cuts bits finely, get deep Kong Shi to discharge bits hard, cutting fluid sheds cutting division not easily. (4) need not when cutting fluid, broach and hole wall grind easily dead. And dirt is very old, deleterious person is healthy. (5) has the appearance plunging into a knife of certain level, make workpiece bursts apart in exit easy generation. 2, the characteristic of casting pig afore-mentioned generation of these problems are not accidental, contacting closely with cast-iron character however. Commonly used cast-iron its characteristic has: (1) hardness is inferior, it is HB176 ～ about commonly 255, but cast surface often has those who take molding sand is crustaceous with oxidation layer, this cuticular hardness is very tall. Additional, semifinished product brim may appear sometimes white mouth is cast-iron, at this moment hardness is extremely tall, it is HB600 about, aggravate broach wears away. (2) intensity is low (point to) of tension, bending strength, and compressive strength and wearability are taller. Accordingly, whole for, auger cut force not quite (relative to Yu Gang character) . And, it is main that in cutting bear axial fights force, the proportion that torque fights force to occupy is not large, use a diameter for example the common twist drill of 27 millimeter, get alloy structure steel (40Cr) and cast-iron (HT15-33) will compare, auger cast-iron reduce 35 ％ only than getting the axial power of alloy structure steel, and torque reduces 57 ％ , if express 5-4. Other brittleness material has similar tendency. (3) brittleness is big, plasticity is out of shape small, cutting bits is collapse is broken, be mingled with has powder. Of broken end account cut bits, bring a few issues, the first, when drilling deep hole, compare difficult eduction; The 2nd, cut bits broken end as abrasive same, at the back of be placed in broach, between first flank and workpiece, produce acuteness clash, make broach wears away; The 3rd, because cut bits,break into flake collapse, auger cut force and quantity of heat to all be centered on point, and the attrition of face of the knife before cutting bits and broach is lesser, with hind the attrition of knife face is main. On face of the knife after the element of these a few respects wears away to basically be in with respect to what decided broach and first flank, actual condition also is such. (The heat conduction rate with cast-iron 4) is inferior, also make heat in metal cutting be centered on cutting point. (5) cast-iron organization compares thick pine, contain black lead, reduced the plasticity of material and intensity, be helpful for cutting. Cementite still is contained in Dan Zhu iron (microscopical hardness is as high as the impurity with very hard etc of 1000 ～ 2300) , very harmful to cutting tool durability. Generation of the hard to avoid in casting casts blemish, be like stomatic, sand holes, cold lie between, white mouth, often bring about cutting blade to molder, or two blade bear is different, make aperture axes deflective. 3, auger cast-iron group of characteristics that get and use by the watch 5-2 is knowable, casting pig (be like HT20-40) can get the grade that cut a gender to be 3, 4, 4, 3, belong to namely get more easily cut a kind. But with respect to its 4 index, Ⅱ , Ⅲ index is high, namely plasticity is inferior, cutting collapse is broken, heat conduction is slow, quantity of heat is centered in point. Accordingly, fundamental the way to deal with a situation is: (1) should make broach carries work as soon as possible, shorten as far as possible the osculatory distance of cutting blade and workpiece, reduce broach cutting blade and the chance that workpiece chafes. Alleged and fast carry work, ask broach is minutely namely feed as far as possible a few bigger, namely rotate speed (N) and feed (the product of F) (Nf millimeter / cent) want big. On the other hand, when broach minutely the deepness that gets is identical, i.e. is minutely feed journey (when Nf) is certain, because cutting blade is advancement of edge corkscrewed yarn, if turn slow (N small) , feed is gotten fast (F big) , namely the pitch of spiral is a few bigger, criterion the total run that cutting blade has taken wants short, the attrition opportunity that cutting blade gets decreased. Accordingly, answer to increase feed as far as possible, choose rotate speed appropriately next. (2) should increase feed, get cut fight force to increase, because this answers,make broach as far as possible sharp. Because get cast-iron axial to fight force,be main part, and axial fights force to be centered on horizontal blade more again, so, repair reasonably grind broach horizontal blade, reducing axial to fight force is main. If excise horizontal blade completely, criterion axial fights force to be able to be reduced significantly, but bring two issues so: The first, centering is bad, want to locate with jig normally; The 2nd, get hard cast-iron when, encounter a bit especially have when casting black skin and white mouth, broach dies easily blade. Because this is unfavorable will horizontal blade is ground completely, should withhold the certain needle that get a heart, but grind more narrowly than getting group of blade getting a horizontal stroke of steel to repair, a few sharper, inside τ of γ of the horn before blade 0 also but somes big. (3) gets heart tip for protection, grind a chamfer of crescent moon circular arc to make the needle that get a heart low come, the 3 needles after cutting work are very fast at the same time cutting, the needle that get a heart molders not easily and wear away, also facilitate search. Although horizontal blade is repaired more narrowly, but those who get pointed Gao Kehe to get steel is basic model close. (4) uses double sharp angle. As a result of broach outside rate of predestined relationship cutting is high, move relative to attrition namely rate is high, because this this part generation is gotten,cut heat much, add cast-iron heat conduction slow, so quantity of heat is centered outside broach to be in along blade needle, cause it to wear away the fastest. Normally, grind give role, form double sharp angle namely (2 ψ 1) , make corner office broadens, improve broach to come loose hot condition, raised durability thereby. Via experimenting for many times, show double sharp angle can raise durability 2 ～ 4 times, if express 5-5. But because grind a double sharp angle, lengthen cutting blade, make get cut torque to have a bit increase. But, auger cast-iron force reduces group of axial that get a lot of, torque increases not much, because this total cutting negative charge still is not big. (The horn after 5) is increased appropriately. Compare commonly those who get steel is big 3. Or so, reduce the attrition between face of the knife after broach and workpiece. According to test result, fc of α of the horn after blade is 13 ～ outside 18. When, the durability of broach is taller. (6) is reasonable use cutting fluid. When some people are getting cast-iron work, do not be willing to use cutting liquid. The likelihood has a few objective factors here, if work is very great, cutting fluid clears not easily; Drossy in contain black lead to make water becomes very quickly black dirty etc. But big to batch bore working procedure, still had better use cutting liquid, can raise broach durability greatly so, improve bore quality, and avoid dirt to fly upwards. But want special attention, cutting fluid should be joined continuously first and last, and discharge wants proper, otherwise a few mixing spiccato current enters hole inside, cause hole wall easily local sclerosis, and drossy and harmonic into abrade like creaming, aggravate broach wears away. (7) should discover " plunge into a knife " phenomenon, need to take measure part appropriately. (8) is used group auger auger cast-iron when the cutting dosage of the choice, can refer to watch 5-6. CNC Milling