Aluminium alloy machines hard alloy high speed to establish the analysis of milling cutter and design

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1 preface progresses as the technique that processes machine tool and cutting tool data, technology of high speed cutting got great progress. Current, famous tool company had international high speed of hard alloy of aluminium alloy treatment establishs product of milling cutter cutting tool. Among them: Product of Jabro Tools company, Fraisa company is relatively mature, set is whole, breed is much; Additionally company of Sandvik company, OSG company, 3 water chestnut, Titex Plus company, Guehing company also rolled out cutting tool of cutting of aluminium alloy high speed. The technology of high speed cutting of our country starts later, till last centuries 80 time end, processing technique of foreign high speed is large-scale apply when, our country just begins to recognize the tremendous progress foreground of high speed processing technique and applied potential. The college of Beijing grain industry, university that be the same as aid was collected 1987 and arranged the research that pursues technology of high speed cutting about the technical data of high speed cutting in great quantities, published article of a few research in succession, after 90 time, national nature fund aided financially a series of high speed cutting the research of relevant technology works, among them Shandong university and college of Beijing grain industry consider to developed a respect to make a large number of works with cutting tool in mechanism of high speed cutting. But the range of products that at present home has not matured, high speed machines cutting tool to rely on an entrance in great quantities, study high speed machines design mechanism, series of cutting tool of high speed of development hard alloy is very necessary. 2 high speed establish the invalidation of cutting tool of design principle relation of milling cutter to have the following kinds of forms, the first, in cutting process, cutting tool ruptures because of intensity reason generation in initiative condition, cutting tool instantly invalidation, this kind of cutting tool is failure for certain, this can be calculated completely with static force analysis, this kind analyses what can say to be FA; The 2nd, because cutting tool is oscillatory,cutting tool is in in cutting process, make cutting tool life and the workpiece that be added cannot satisfy real requirement, it is FS to what the oscillatory analysis of process of cutting tool cutting says; The 3rd, face of the knife after cutting tool is mixed as a result of the horn before cutting tool in cutting process wears away too big or the small collapse blade as a result of cutting tool, make cutting tool cannot satisfy a requirement, this is face of the knife after be being mixed as a result of face of the knife before cutting tool bears cut bits and already machined face pressure, generation attrition, special fall in high temperature condition, cutting tool hardness is reduced, wear away more easily, this kind of analysis says for FM. General, in cutting tool design, cutting tool intensity must assure above all, it is vibration next, final ability is FM. That is to say cutting tool design puts in the following relation: FM} of → of D={FA → FS at the same time FA, FS, FM also is not isolated, also contact each other between them, as cutting tool wear away, cutting tool angle produces change, cutting force also as rise, vibration of cutting tool happening and the possibility that break off increase, cutting tool vibration increases, the damaged that also quickening cutting tool at the same time and break off. As a component of cutting tool, high speed establishs the design principle of milling cutter to build the base in this relation likewise, FM of → of FS of the → that press FA undertakes an analysis to cutting tool, obtain cutting tool parameter, have proof. 3 finite yuan of analysis in high speed the application in establishing milling cutter to design begins seventies from 20 centuries, finite yuan of imitate that the law is machined at cutting by application namely, obtained a few result, through development of a few years, no matter be abroad or home, have the research positive result that comparative, finite yuan the law applies at analysing cutting craft gradually, forecast workpiece, cutting tool and the temperature in cutting bits to distributing, analyse what whole establishs milling cutter to bend be out of shape, the stress that studies integral hard alloy establishs milling cutter distributings reach destroy a form to wait. From the point of these research achievement, finite yuan what the analysis begins to be used at cutting is mechanical decide, include to cut the formation of bits and condition of in-house stress meet an emergency, field of temperature of main research cutting distributings and vibration of research cutting tool and invalidation, total trend is from mechanism research transfers to use a technology. However, how to study high speed machines the design that establishs milling cutter and workmanship, how to decide the rationality of the design, and how do the design with specific guidance and craft ask, in the research of this respect, the data of abroad and domestic university still basically is blank. The article undertakes study in the light of above blank, in establish after high speed establishs the cutting force model of milling cutter and design principle, apply finite main to 3 of design relation factor has yuan of analysis way one by one analysis. 1.

Cutting tool of FA of static force analysis breaks off stress analysis cutting tool breaks off to basically have the following kinds of forms: The first, high speed milling cutter wears away gradually in point of the cutting tool in use process, cutting force increases gradually, bring about cutting tool invalidation finally, be like right now change a knife not in time, will bring about cutting tool to break off; The 2nd, because too fragile or cutting tool is opposite cutting dosage is too big, cutting tool bears cutting power is too great, bring about cutting tool to break off. Application is finite yuan of analysis, can get cutting tool gets power weak point, in the design the key considers and design: Graph distributinging graph of stress of 1 static state from the graph 1 can see, cutting tool folds breakpoint to center a dot in two stress, be in to stand by collet, shrink for cutting tool diameter place, shrink among them the stress concentration of diameter is more apparent, rupture extremely easily here. Shrink to cutting tool neck place, as a result of the effect that stress focuses, notice all the more when the design, should if pursue,2 round glide are crossed. Graph 2 shrink B of graph of neck place enlarge.

Structure of blade of cutting of analysis of stress of point of blade of cutting of high speed milling cutter analyses a scheme stress of 3 point static state distributings in process of high speed cutting, point of a knife bears come from workpiece presses stress with what cut bits, bear area of press press stress presses a plan in analysing a process computation of 3 shadows part, pass finite yuan of analysis, if pursue,4 are shown. Pursue chart of parameter of 4 cutting tool different expresses milling cutter of 1 high speed and differential seat angle of common milling cutter cutting of cutting material high speed is common point of 2-5 15 5-10 6-8 of alloy of titanium of cast-iron 0 12 5-15 4-6 of common steel 0 16 10-20 5-8 analyses 12-15 13 20-30 8-12 of aluminium alloy of the horn after the horn before the horn after the horn before cutting machine place of high speed milling cutter to use hard alloy data succumb intensity, but brittleness is big, main damaged form bursts apart for brittleness, namely we often say " collapse blade " . Once high speed milling cutter dies after blade, the attrition force of cutting blade and workpiece interface rises quickly, cutting tool wears away accelerate, cause the early failure of cutting tool. Graph the result of stress analysis plan of milling cutter of breach of 5 cutting first flank analyses: Below identical cutting parameter, the milling cutter of complete cutting point, value of point point stress is the greatest, and milling cutter of breach of cutting first flank, stress maximum appears around breach. Apparent, the breach of edge makes the generation stress of area is centered near breach, cause the early failure of cutting tool. Design process must want to consider to machine craft, in order to assure good point. Oscillatory analysis is in process of treatment of high speed cutting, oscillatory (the vibration that includes a machine tool, the vibration of cutting tool) very big to the treatment quality influence of workpiece, the vibration with periodic at the same time cutting tool makes edge produces micro-crack, the generation of micro-crack and patulous, cause the early failure of cutting tool, study oscillatory law so very be necessary. Cutting vibration is formulary: Graph formula of 6 cutting vibration can see from inside afore-mentioned formula, the factor that affects cutting vibration basically is: Cantilever length L, sectional stiffness I, arbor diameter D, cutting deepness D, feed F, yang model measures E to wait. The analysis undertakes in the light of each elements below: What cutting tool hangs the influence that extends length to change to distributing to cutting tool stress is finite yuan of data that analyses concrete analysis be: Cutting tool is dangerous when extending length to be 85mm, cutting tool clip holds a share maximum of around area stress is 438.

5Mpa; Cutting tool is dangerous when extending length to be 75mm, cutting tool clip holds a share the stress value maximum of around area is 324.

15Mpa; Cutting tool is dangerous when extending length to be 65mm, cutting tool clip holds a share around area stress is 279.

28Mpa. Apparent cutting tool is dangerous extend bigger, cutting tool clip holds a share value of around area stress is greater, cutting tool happens more easily in process of high speed treatment to break off in this area phenomenon, so, below the premise that asks in contented treatment, what reduce cutting tool as far as possible is dangerous extend length, those who avoid cutting tool is abrupt break off. After Yang model measures E to decide when arbor material, yang model quantity is certain amount, data is as follows: Yang model measures arbor material (E)(Kg/mm2) hard alloy 5.

104 heavy metal of 3 × 2.

104 steel of 9 × 2.

1 × sectional stiffness of I of 104 sectional stiffness basically is concerned with the diameter of cutting tool, but establish milling cutter to high speed for, must consider the characteristic of structure of its cutting part, helix chamfer, hind horn, before horn have bigger effect to tigidity, affect the vibration of cutting tool thereby. Also get confirming in experimental process, the change that wait is opposite the horn after horn is mixed before and helix angle to have corresponding effect to cutting force each, have particular concern with oscillatory frequency and extent at the same time. In other condition affirmatory circumstance falls, through building cutting tool parameter and oscillatory mathematical relation model, the cutting tool that set optimizes joins numerical value, can get cutting tool force vibration control is inside good range. Graph 7 cutting tool hang the equivalent stress when extending length to be 85mm D of graph cutting deepness, feed F using finite in yuan of analysis and the process that design a model to build, cutting deepness D, these cutting parameter such as feed F are not here to oscillatory influence discussed. When dynamic balancing analyses cutting of high speed of knife establishing mill, get not just the action of cutting force, and the influence that still is left mental efforts. If pursue 8, 9 are shown, fc(x of cutting component of force to go to establish milling cutter to twist change form) , fcn(y of radial component of force to go to establish milling cutter to bend be out of shape) with Fa(z of axial component of force to cause those who establish way of axes of milling cutter edge to compress be out of shape) , afore-mentioned is out of shape cause point of a knife to be in X, Y, z3 directional change. (Element of A) centrifugal force (element of B) cutting force (Model1)(n=10, 000r/min, dc=10mm, be out of shape unit: M) graph 8 centrifugal force and cutting force are right the Xy of cutting tool to be out of shape (dot of A of point of a knife is in) the influence is being designed dynamic balancing issue must consider in the process, g is balance character (Mm/s) , mirror cutting tool counterbalance and the parameter that rotate speed concerns namely: In type of M of × of N 30 M 30 of × of U of × of × U = P of G=w × E= PN: E -- prejudicial (G × Mm/Kg) M -- cutter hub quality (Kg) W -- angular velocity (R/s) M -- lopsided quantity (G)N -- rotate speed (Rpm) R -- lopsided radius (Mm) U -- remains is lopsided measure (remains of G × Mm) is lopsided, 000r/min, dc=10mm, equivalent stress unit: PA) pursues the influence of the greatest to cutting tool equivalent stress reduces 9 centrifugal force and cutting force Zhen Leng is other, in milling cutter of high speed force hind the area that intersects with cutting blade on knife face raised a petty arris area, the purpose is to reduce cutting force, better reduce vibration. 3.

The stress in treatment of fatigue analysis high speed distributings in process of high speed cutting, edge is cut often, cut, make every second stands cutting tool point hundreds of times the hammer of workpiece is attacked. If the graph shows 10 times: Graph the geometrical parameter that the design of cutting tool of 10 stress distributinging analysis needs to notice adequately to optimize cutting tool, get used to change of such high-frequency stress. High speed milling raised taller requirement to cutting tool, milling cutter of high speed force should have very strong impact resistance not only more important have even very good high temperature resistant quality. Graph cutting of distributinging high speed of the temperature in treatment of high speed of distributinging chart of 11 cutting temperature and common cutting are different, common cutting impact resistance is mechanical and fatigue damaged, high speed cutting is in treatment process, it is all round cutting blade generation high temperature, make blade of cutting tool cutting local molten, the mechanical function such as intensity hardness drops, of this pair of cutting tool wear away and cut bits, the impact with the very big attrition between cutting tool, and quantity of heat is commonner cutting more center at point, cause point to be in very tall stress and temperature gradient, make the cutting tool when high speed milling easy the brittleness damaged such as generation collapse blade. Those who pass pair of high speed to machine cutting process is finite yuan of analysis, can imitate goes out whole the process of the formation that cuts bits, the trends of field of the temperature in dividing separate out to machine a process in cutting thereby distributings. Serving as the exhaustion of cutting tool to wear away is hot exhaustion wear away and mechanical stress tatty is integrated, through cutting tool parameter and two kinds of tatty the relation will optimize a design effectively. 4.

The characteristic of cutting of aluminium alloy high speed and to the demand picture of cutting tool 12 low speed machine what machine with high speed to cut bits to be out of shape in aluminous treatment process, be out of shape as a result of aluminium alloy plasticity big, cutting rate is higher, rate of the flow that cut bits is more than cutting to be out of shape speed, cut bits to have not enough time to be out of shape namely from hind knife face is poured out of, if the graph shows 12 times: OA of F → cutting tool cuts an area to bits is cut when low speed, OB cuts an area to bits is cut when high speed cutting, when high speed is machined, cut horn to will greaten, be out of shape coefficient decrescent, be out of shape coefficient is close to at 1, so cutting is out of shape the quantity of heat of generation is very few, but the pressure of face of the knife before be opposite increases, major quantity of heat comes from the attrition that cuts bits and where a thing can be put to best use, reduce what attrition heats up effectively to generate one of characteristics that are design of high speed milling cutter. The requirement that the requirement that designs to cutting tool designs to cutting tool basically is to seek the means that reduces attrition heat: Use coating medium or before craft of knife face polish improves the appearance bright and clean degree, cutting of the horn before the attrition obstruction when reducing treatment increases is light, the design Gash horn of the horn of cutting force GASH when reducing treatment and small chamfer and small chamfer basically are look bits and the action that discharge bits. In process of high speed treatment, it is very important to cutting tool to cut bits to eliminate smoothly, but small chamfer and GASH part are too large, will reduce intensity of ministry of cutting tool blade, be restricted through be being had to the knife yuan of analysis, set safety is worth, OK and effective design. 4 summary put forward high speed to establish the design relation of milling cutter on the foundation that the article is analysing to form of cutting tool invalidation: The article applies FM} of → of D={FA → FS finite FA of main to 3 of design relation factor, FS, FM undertook yuan of analysis law be analysed meticulously one by one, decided high speed establishs milling cutter the standard of good structure characteristic. The to high speed milling cutter structure on the foundation that the article is analysing undertakes optimizing designing, apply acquisition theory to come to what guidance machines craft make. CNC Milling CNC Machining