The application of cutting tool of high speed cutting

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1. The research history of cutting of foreword  high speed, can restrospect to 20 centuries the concept of the cutting of concerned high speed that 30 time put forward first by German Dr. Carl Salomon. The research of Dr. Salomon broke through the understanding of traditional cutting theory to heat in metal cutting, think heat in metal cutting is with cutting inside limits of traditional cutting speed speed is shown only drab increase function concern; And after breaking through certain limit when cutting speed, cutting temperature increases along with the addition of cutting speed no longer, can reduce along with the addition of cutting speed instead, show inside the limits of higher rate with cutting speed namely drab decrease function. 50 time later period begins, the experiment of high speed cutting begins to enter all sorts of experiment research again, the mechanism of high speed cutting begins what to be known by scientists. Began to be studied by German government technical ministry is aided financially 1979, institute of PTW of German Darmstadt university takes the lead, the research that the research group that waits for many sided to be comprised jointly by manufacturer of university research organization, machine tool, tool manufacturer, user developed a system to high speed milling. Besides mechanism of high speed cutting, the applied solution of the many sided such as parameter of the machine tool in studying milling of high speed of group synchronism thrash out, cutting tool, craft, the domain such as the treatment of aluminium alloy of preexistence of circumstance right-hand seat that makes high speed milling is machining mechanism to have not get complete consensus and hard data treatment gets applied, the treatment demand that resolves the domain such as mould, car, aviation, obtained enormous economic benefits thereby.  looks from current trial, as cutting speed rise stage by stage, when cutting be out of shape the rule produces a few changes. The cutting in cutting bits is out of shape gradually aggravate, the slippage that cuts an area is strengthened gradually, even if the configuration cutting bits of plasticity material, also meet gradually from banding the change that cut bits is dentate cut bits, transform likely then cut bits for unit shape. Because the meeting that cut bits leaves in the condition of high speed cutting by banding the change that cut bits cuts bits for unit, cut bits and before one of main source that the attrition of knife face will be cutting force and heat in metal cutting no longer; Same as a result of cutting speed rise, the flexibility that knife face handles workpiece material after is out of shape because be out of shape speed does not follow gradually,also will go up cutting speed and decrease, hind the attrition of knife face also decreases because of this, produce beneficial effect to reducing cutting force and heat in metal cutting thereby. Because this is when high speed cutting, main heat in metal cutting will by cut bits to derive, and the temperature rise of workpiece and cutting tool is very small, high speed cutting also is become " cold conditions cutting " . Cutting of  Germany high speed studies the group thinks, the 5 ～ that the speed limits of high speed cutting should be traditional cutting speed 10 times. And the issue that cutting of implementation high speed may involve a lot of aspect such as parameter of machine tool, cutting tool, workpiece, craft. The cutting tool of cutting of high speed of article put up with and other concern a certain number of respects related element and cutting tool to introduce a few his views.  2. The interface  of cutting tool and machine tool is in conventional boring mill treatment, what we use normally is all sorts of 7:2The cutting tool interface of 4. The main shaft end panel of these interface and cutting tool are put in clearance, in main shaft high speed rotates and the action of cutting force falls, the main aspects aperture of main shaft expands, cause cutting tool axial and precision of radial fixed position to drop. The axial dimension of awl handle and weight are greater at the same time, go against the miniaturization that changes knife and machine tool quickly.  and the interface standard that high speed machines us to be able to recommend a kind of new HSK that be called normally. The new-style knife that HSK is machine tool of high rotate speed technically to develop by institute of machine tool of university of German A go smoothly, machine interface, formed use at changing knife and hand automatically to move to change knife, center refrigeration and end panel refrigeration, common model and compact model wait for 6 kinds of forms. HSK is a kind of small taper (1:1Of 0) hollow short awl handle, the end panel when using and cone are contacted at the same time, form tall osculatory tigidity thereby. Via analysing research, although HSK joins,meet as much in the main shaft when high speed rotates outspread, but the contact that still can keep good, the join tigidity impact of mouth of rotate speed butt joint is not big. 3. The balances  physics principle of cutting tool makes clear, the quality of the centrifugal force of the particle in rotating and particle, particle and the distance of runner shaft coming back and rotating angular velocity (perhaps rotate speed) just become direct ratio 2 times. That is to say, if rotate speed increases 1 times, centrifugal force will increase original fourfold. This is meant spend in high rotate speed coming back below, the treatment precision of cutting tool and life are left the serious effect of mental efforts possibly. Manufacturer of some accurate boring cutter chooses two boring cutter to have a test, have boring tool of essence of life crossing dynamic balancing beforehand only among them. What these two boring cutter machine the circularity of aperture to do not have what difference when 5000r/min, it is 1.

1 μ M, because the precision of system of machine tool tool is caused,these errors basically are; And rise when rotate speed 1 times arrive when 10000r/min, the circumstance differred apparently. When the circularity that machines the opening that give through the boring cutter place of the balance compares 5000r/min, increase somewhat, for 1  25 μ M, and when the circularity that machines the opening that give without the boring cutter place of the balance compares 5000r/min, increase a lot of, achieve 6.

30 μ M, be the boring cutter that adjusts through the balance 5 times much. Accordingly, to rotating in high speed the cutting tool that next use must undertake balancing adjustment.  according to balance theory, of swing tower lopsided can divide it is 3 kinds:  (1) static unbalance: Static unbalance is to have a lopsided quality only and this are lopsided quality is located in two bearing in the middle of, the size that accordingly its are rotating to leave mental efforts mediumly to return power on two bearing and directional homogeneous phase. In cutting treatment short dangerous extend cutting tool (be like dish kind of cutting tool) can thinking approximately is static unbalance only. (2) couple unbalance: Have two lopsided quality, distributing in semmetry the 180 ° position at bearing midpoint, the size that accordingly its are rotating to leave mental efforts mediumly to return power on two bearing is equal way is opposite however, those who form is a couple.  (3) dynamic unbalance: Have two or the lopsided quality of two above, distributing not to accord with the rule of above, the size that its are rotating to leave mental efforts mediumly to return power on two bearing and way are different. Such OK thinking, dynamic unbalance is the overlay of static unbalance and couple unbalance, lever kind cutting tool is for the most part this kind is lopsided. The elimination with lopsided  has accentuation, go weigh and adjusting 3 kinds of methods. Of cutting tool leave factory the method that uses bore to weigh more evenly beforehand, be measured in classics balancing machine namely and the seat that computation gets, drill a hole that appoints size and deepness, in order to make cutting tool is in this position is sectional on get static balancing, perhaps be in two to get a Kong Yishi to show dynamic balancing each locally.  but because dislocation cutting tool changes the minim with new generation of the meeting after bit and fittings is lopsided, integral cutting tool also can be after loading knife handle on whole form some kind of minim lopsided, we come via often can using setting method purify is lopsided the quantity balances a purpose with achieving. Setting method basically has 3 kinds of kind:  ① adjusts annulus evenly: The knife handle that cutting tool of whole of the installation in high speed treatment uses basically uses this kind of means, there are two balances to adjust annulus on knife handle normally. Adjust annulus evenly through rotating respectively, can produce a join forces and a counterbalance moment, realize dynamic balancing thereby.  ② adjusts bolt evenly: Dish kind cutting tool can use this kind of means. This kind of method is passed normally be in (or two) sectional inside undertake to two bolt radial shift will change this sectional the centroid position inside, achieve the goal that adjusts evenly thereby.  ③ adjusts evenly piece: The odd blade cutting tool of large size (boring cutter of the blade that be like sheet) can install a balance to adjust normally piece. Should adjust piece with Chan Ren knife head is in same and sectional, radial can move, adjust through this piece shift will achieve a balance. Besides afore-mentioned balance methods, reducing cutting tool weight also is an effective method. If Waerte is used at the cutter hub of the cutting tool of cutting of aluminium alloy high speed,the aluminium alloy with high strenth is made. 34 what be steel only as a result of aluminous density.

6% , the centrifugal force below same production precision also decreased greatly. It is with the milling cutter of diametical 200mm exemple, opposite at milling cutter of cutter hub of identical diameter steel, the weight of cutting tool by 9.

8kg decreases 3.

7kg, the top rotate speed that allows to use also raises 13200r/min from 4200r/min. The cutting tool that  uses to be below condition of high speed cutting, dish kind of cutting tool because axial dimension is relatively lesser, can undertake only commonly static balancing; And lever kind of cutting tool dangerous extend longer, the included angle that the likelihood exists between its quality axes and axis of rotation cannot by oversight, because this must undertake dynamic balancing. What must make clear is, be in two only or two above are sectional in the balance that have adjusts ability may be dynamic balancing, and in sectional inside the balance that have should be static balancing.  is general the rule, the structure of central semmetry suits high speed treatment more. If the 3 tine structure of central asymmetry is medium, had aged only center, this cutting tool does not suit to regard high speed cutting as cutting tool commonly; And the 2 tine structure of central semmetry, its two tooth all cross a center, suit high speed cutting quite. Same, belt because cut smooth purify,cut smooth columnar knife handle the partial data of cutting tool a side, what also caused cutting tool is lopsided, to high speed cutting also be adverse; Add its to use bolt normally from flank impaction, make the clearance of the installing hole on knife handle and cutting tool petiole turns into in clamp process asymmetry clearance, the lopsided likelihood after installation by aggravate, do not suit to be used at high speed cutting more. Accordingly we choose in the cutting tool of high speed cutting want in the process mature the influence of its structure, avoid cutting tool construction lopsided on the principle. Because be passed normally,adjust can the lopsided amount of purify is quite limited, and on the principle lopsided often be head and shoulders above knife handle to adjust the lopsided range that can eliminate. We think, the cutting tool that tool supplier should provide to oneself whether use at high speed cutting to make bright show. Now, the symbol that a lot of Euramerican tool business had indicated to express to apply to high speed cutting on the propagandist data such as its example " HSC " or the symbol that applies to high speed treatment " HSM " , accordingly, express what did not tag this kind of symbol commonly not to suit high speed cutting.  4. Security  needs higher rotate speed normally as a result of high speed cutting, make cutting tool allots the possibility that gives birth to broken, disintegrate to increase greatly in effect of tremendous and centrifugal force. This kind of problem not only exist, and have not little risk. If Shandong university uses home of the diametical 100mm of some famous manufacturer production but dislocation face milling cutter installs single bit to undertake cutting experiments, when rotate speed increases 5000r/min, an only razor blade carves more than in centrifugal force fly below the circumstance of an attrition force left cutter hub, stroke is in of the machine tool defend on armor plate; And an user of Suzhou is more unfortunate, the fragment after their cutting tool is broken hit the ballproof glass of the machine tool, the result is glass is attacked completely to break. So, why can the cutting tool that high speed machines be like this to destroy ability greatly? We made the brief analysis that be as follows. If of 40mm of a diameter but dislocation milling cutter undertakes machining with the rotate speed of 40000r/min, its linear velocity is 5024m/min, namely 83.

7m/s, with bit weight 0.

015kg computation, its momentum is 1.

26kg · M/s. This one result and the momentum giving chest of bullet of one famous small voice handgun comparatives (weight of warhead of this handgun bullet is made an appointment with 0.

005kg, initial velocity giving chest is 230m/s, accordingly momentum is 1.

20kg · M/s) . The structure of milling cutter of type of  razor blade and security have very big concern. The milling cutter that the bit that Shandong university institute uses flies off, it is home use generally carve a type clamp means. Means of this kind of clamp relies on attrition force completely to resist centrifugal force, bit flies off more easily, and the cutting tool that uses bolt clamp means needs clipping bolt to just can bring about bit to fly off, security rises greatly. Consider to make clear, the milling cutter that uses bolt clamp as rotate speed rise gradually, bolt can be below the action of centrifugal force be spun, cutter hub also can happen to expand slightly. Already amounted to critical stress when 30000 ～ 35000r/min about and appear permanent drawing is out of shape, and before achieving critical rate, bolt has appeared curve a phenomenon, cause clamping force to drop, bit also produces displacement subsequently.  because this, we must notice high speed machines the security problem of cutting tool adequately, put an end to safe accident produces when high speed cutting. The high speed that the working group of cutting of German high speed puts forward at this point machines standard of technology of cutting tool security to be suggested to make German standard and international standard already. This standard sets: To the cutting tool of bit type, manufacturing business must assure to be in 1.

6 times at the biggest use rotate speed (Np ＝ 1.

6nmax) next experiments, of cutting tool permanent be out of shape or the displacement of the spare parts does not exceed 0.

05mm, and be in 2 times at the biggest use rotate speed (Np=2nmax) next experiments, cutting tool does not happen explode broken; To integral type cutting tool, should experiment below Np=2nmax condition and do not happen to bend or rupture. At the same time business of requirement tool production must is opposite the cutting tool that can be used at high speed cutting bright show its the biggest use rotate speed. The security that uses cutting tool below this condition will get sufficient safety assures. Of course, to be not cutting tool of high speed cutting, do not need such requirement, top rotate speed sets the check and ratify that accordingly we answer to be offerred strictly according to manufacturing business when choosing cutting tool of high speed cutting. Because home still does not have the security standard of cutting tool of high speed cutting, we need when choose more discreet. To the cutting tool of high speed cutting, we should adopt certain measure to assure its security. For instance, waerte asks to be opposite the bit type cutting tool of high speed cutting, use bolt of locking of former plant razor blade in order to assure security; When bit is installed, assure to set torque; Change 5 times in bit at the same time hind, use new bit locking bolt to cause clamping force because of exhaustion in order to prevent bolt to drop, the safety that affects cutting tool is used.  is same, cutting tool produces business to also should adopt measure to strengthen cutting tool to machine medium security in high speed. A few famous cutting tool of foreign produce business to be in recent years in the development of bit type cutting tool the security that used technical measure to strengthen cutting tool in succession, centrifugal force increasing to uninstall a structure between bit and cutter hub is among them one of. The milling cutter that takes centrifugal force to uninstall has one raised on cutter hub, of bit have an indentation locally accordingly, the centrifugal force of bit can be mixed by the attrition force between bit and cutter hub, bearing force of bolt the bearing force that uninstalls a structure from mental efforts is assumed jointly, such resisting the ability that bit flies off got strengthening. 5. The material  of cutting tool of high speed cutting although we always hope to get having tall hardness already in order to assure the wearability of cutting tool, again tall tenacity prevents the disintegrate of cutting tool, but the cutting tool material that current technology develops to had not found so superior performance, fish and bear's paw cannot hold concurrently, accordingly, we can be in actual in choose righter cutting tool stuff according to need: The tenacity of material of first consideration cutting tool when rough machining; The hardness of material of first consideration cutting tool when finish machining.  diamond, cubic nitrogen changes the technical long-standing of boron and pottery and porcelain, their common characteristic is hardness tall, brittleness is big, cannot bear bigger impact. And in recent years the development of film technology, make fine grained hard alloy is in maintain its taller tenacity while, raised its to fight high temperature and the ability that fight concussion load, apply for high speed cutting more economic cutting tool offerred a technology to assure. If  is made of baked clay the skill of Tiger · Tec that Er spy company establishs (also say " tiger razor blade " ) , used special film technology to make the around knife face of bit appears respectively black and aureate two kinds of color, the join structure between film of alumina of face of face of the knife before passing improvement again and fundamental film, enhanced the strength of film, the ply of layer of oxidize aluminous film got buildup, of bit fight high temperature capability to rise greatly. Because the unit of bits condition is cut to change when high speed cutting, tiger razor blade from basically suit to machine cast-iron treatment, patulous to suit cast-iron treatment not only, suit steel as much treatment. The knife sheet that there is to name WQM35 in the product of series of Quar · Tec that Waerte rolled out 1999 is qualitative, this material has 100 film character. These 100 film total ply is 6 ～ 8 μ M, the ply of monolayer is 20 ～ 50nm for the most part. Because film is in high speed cutting, especially below high speed milling, get numerical value is not great but the impact that makes frequency conversion lead very high cutting power and heat in metal cutting, form tiny breach dilate extremely easily crackle, reduce the adhesion between velar layer and velar layer, film layer and matrix thereby. Accordingly, the hard alloy that we suggest to choose film when rough machining (especially) of fine grained hard alloy, diamond of the choice when finish machining or cubic nitrogen change boron.  6. Treatment of high speed of  of strategy of high speed treatment may cause high metallic excision rate, because this is when rough machining,must check what what its need twist be apart from the torque that whether exceeded a machine tool to be able to be offerred with power and power. Machining aluminium especially when, because its treatment rate is extremely high, its are needed to may cause the value that exceeds us to imagine. It is with the corn milling cutter of 32mm diameter exemple, if in order to make an appointment with the linear velocity of 1000m/min (corresponding rotate speed undertakes mill chamfer for 10000r/min) about, should cut deeply when 10mm, its power is used up is 19kW about, and should cut deep if increasing 30mm, power is used up will increase about 56kW. Accordingly, our proposal is:  increases cutting time as far as possible in high speed treatment the scale in whole working hours, decrease be not handling time (if change a knife, adjust, the) such as idle stroke; He Lixi machines  face mill: The cutting tool that adopts small or medium measure and statified the treatment of cutting is politic; When groovy mill is machined, use statified cutting, small cut deep, medium feed. Because cutting rate is high, can get high feed rate likewise.  still has a few particular treatment notes: (When milling cutter of 1) ball head is used, should notice its are close speed of central part cutting is dinky, be close to Yu Ling, cutting condition is accordingly more abominable. Possible sentence, the normal direction that should be milling cutter axes and workpiece has a banking angle. The basis experiments, when this included angle is controlled for 15 ° , the life of cutting tool will reach great value.  (of 2) cutting tool hang the cutting tool life in extending pair of high speed to machine to will produce a few effects. Finite test result looks, when 6mm establish milling cutter to hang when extending length to increase 60mm from 30mm, cutting tool life is expected to increase to before 140% to 230% .  (3) is in copying, the milling means of outline of edge cross section (call again wait for Gao Xi) even if excel edge is sectional the milling means of outline (call mill climbing slope) again. Because wait for cutting condition of Gao Xi to agree quite, cutting is smooth, the surface roughness case of workpiece surface is better also, and conditional pole does not stabilize the cutting of mill climbing slope, cutting tool is close to central part to produce collapse blade extremely easily, the surface roughness case of workpiece surface is not good also. When the case that uses mill climbing slope, the experiment makes clear, the excel of cutting tool life of suitable mill goes against mill, up the cutting tool life of mill wants excel to be down mill.  (4) is when milling interior antrum, when cutting tool feed is in to corner, because cutting wraps horn to increase suddenly, its radial load can increase quickly, peak value can achieve normal cutting to be worth 170% the left and right sides. Accordingly, we suggest to be carried out in turning point so called " cycloidal cutting " , increase suddenly what can avoid cutting strength so, realize smooth cutting thereby, prolong the life of cutting tool. (5) should try in cooling respect special attention. Oily mist is cooling (say to allow to do cutting again) it is better method, refrigeration of jet refrigeration, interior of high-pressured large flow also can be accepted, but should avoid low pressure, external cooling means.  7. Cutting of epilogue  high speed is an advanced integrated technology, must mix machine tool of high speed cutting, high-powered cutting tool the union of optimal treatment engineering technology that machines a spare parts rises, ability produces the advantage of technology of high speed cutting. CNC Milling CNC Machining