Improve the service life of the cutting tool when mill is machined

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  • source:JUSTYN CNC Machining
Manufacturing technology institute (the positive result that WBK) studies makes clear, cutting can decrease to wear away greatly when the cutting tool mill that uses passive damping cuts treatment horniness material, raise the durability of cutting tool. Through action of press close to the point changes percussive of milling cutter entrance to decrease brace up measure, can produce distinct effect to the service life of cutting tool. Through using steeliness bolster plate, roll of hard metal of counterbalance service life and former outfit is strong cut board photograph than increasing 176% plans graph of force of 1 Utopian cutting the 2 milling head tool carrier of bolster plate are tall hardness material or surface are easy fragile the milling treatment that cracks material, mechanical and alternant load is high when as a result of milling cutter the entrance is pounded, meet those who bring about cutting tool probably wear away increase, guide thereby cause with loss of life. Same, undertaking to outline discontinuous or when be being machined to car of material of out of round, also can produce this kind of situation. Institute of technology of production of university of be stranded of Si Lu blocking Er (WBK) is studying, how can fall in the circumstance with other cutting changeless parameter, the method that changes material of bit bolster plate locally through be in what action of press close to nods will produce positive effect to cutting tool service life. We will prove hereinafter, decrease in passivity brace up how does the flexibility on milling cutter change, it arose why to be planted to the service life of cutting tool influence. In addition, also did metabolic test to the flexibility of lathe tool in turning process before, the test result result of this kind of test and milling process tries to compare now, introduce the conclusion that next laboratory reach. When mill is machined, cutting tool is bearing to be caused because of technique hand in change bear. This kind of bear has mechanical quality, also have hot quality. In mechanical bear respect, what be worth to be carried particularly is the entrance concussion of bit. The instant of material is entered in edge, cutting force can produce apparent promotion. For example, be the same as in feed to when undertaking milling, the blade ministry of cutting tool is in when entering data every time, the entrance that can experience cutting tool is pounded. Graph 1 in gave out curve of ideal cutting force change. Because this kind of effect is fragile hard oxidation layer and got be strengtheninged apparently, casting the regular meeting on workpiece or similar work to produce this kind of situation. Lubricant is strengthened hand in change bear on one hand, the process heat that cutting tool conducts can increase the thermic load of cutting tool; On the other hand, the temperature change that edge cut air causes also can increase the thermic load of cutting tool. Because used lubricant, heat is handed in change bear returns can farther aggravate. Manufacturing technology institute undertook to be studied by Germany association is aided financially " the flexibility when through cutting tool the entrance is pounded changes, the service life that improves the cutting tool when cutting is machined " project. This project discussed mechanical overload negative charge, prove to pass what nod in action of press close to to change flexibility locally through the experiment can as far as possible reduce negative charge of this kind of mechanical overload. Starting this matter that studies a project is the result that in be based on multinomial before job, obtains. These results can prove: The tigidity of machine tool actuating device is to have certain effect to the service life of cutting tool. For example, the machine tool cutting tool of the actuating device with the not quite more powerful than using tigidity machine tool that uses main shaft of expensive rigid electric machinery wears away more quickly. But have a lot of advantages as a result of the itself of electric machinery main shaft that uses in great quantities at present, have the possibility of a kind of choice consequently, cheap and cost of this kind of choice is right flexibility, and the parameter of service life undertook optimizing, and need not change drive plan. Traditional lathe tool rushs in roll cut fill up below bit have the horniness metal bolster plate with abrade course, in order to make sure bit position is firm. In bolster plate the circumstance with other changeless parameter falls, we were done to the material of this kind of bolster plate revise. Similar the test that the early days phase in this project does on lathe. Above all, developed tool carrier of a kind of milling head, the material that it allows to differ flexibility is put to cutting tool. To make experiment result and the result that foregoing turning experiments obtain are had as far as possible tall can compare a gender, milling head tool carrier the design was become can put the identical roll in experimenting with early days to develop cutting tool piece. Graph 2 in showed the milling head tool carrier of bolster plate, bolster plate outfit rushs in roll cut bit and cutter hub between. When what the choice uses the data of bolster plate, consulted the test result of early days, discover intensity is not high at that time with modulus of elasticity not old stuff does not suit. The paper of material colophony soak that the experiment uses (glass of 7GPa) of modulus of elasticity, acyl radical (4GPa) , magnesian (40GPa) and aluminium (70GPa) makes clear: Intensity is insufficient, modulus of elasticity is too small, can bring about flexibility to had been out of shape big, partial plasticity has been out of shape big, they offsetted the prestressing force of cutting razor blade, cannot continue use quite consequently. As a result of this kind of reason, bolster plate material can choose the stuff with intensity and more expensive modulus of elasticity only. Specific will tell, it is 110GPa) of modulus of elasticity of cast-iron material EN-GJS-250(, EN-GJS-600(170GPa) , and rolled steel S 235 JR(210GPa) . Because be below the circumstance with changeless dimension,the standard that the modulus of elasticity that uses bolster plate regards a mark as the gender is, modulus of elasticity is the only variable of bolster plate flexibility. But dislocation knife segment cracked the standard that makes service life to raise two requirements to workpiece material, it is them in economy the meeting in quick moving procedure makes cutting tool wears away, 2 it is to want to be able to get applied in day-to-day cutting work. What choose finally is a kind of aluminium alloy (AlSi10Mg) , it is one kind is contained multilayer of black lead cast-iron (EN-GJS 260 Gr) , and steel of a kind of structure (S 235 JR) . The standard of service life is: Detect when measuring cutting force to lift but of dislocation razor blade rupture. The definition of service life is but before dislocation razor blade ruptures can the concussion that susceptive edge enters the mouth. The parameter of cutting experiment process that the part suggests maximum chooses more than presses the cutting material that takes a picture to answer and place to use but dislocation razor blade undertook adjustment, make edge is in an appropriate time paragraph inside happen rupture. This is meant fall in particular case, the adjustment of parameter must the maximum that prep above production manufacturer suggests. The bolster plate that the avery kind of among 3 kinds of material differs with 3 kinds undertook S 235 JR, EN-GJS 260 Gr and AlSi10Mg combine. In 9 kinds of possible combination, every series does a test 10 times, run bit to rupture all the time. In addition, when undertaking machining to structural steel, the former outfit bolster plate that creates company of Binger Walter AG of manufacturer T ü with cutting tool had a test likewise. The cutting test that does with aluminium alloy place did not obtain the result that can use. Although be in,the cutting speed between 500m/min and 3675m/min has change, also did not bring about in the edge inside the proper time Duan Zhi that can foreknow rupture. Listed only so the result that processes steel and cast-iron data. Graph graph of modulus of elasticity of 3 bear commutation, and the average that uses place of stuff of S 235 JR to make test series pursues quite graph of modulus of elasticity of 4 bear commutation, and the load that before the average that uses place of stuff of EN-GJS 260 Gr to make test series machines material of S 235 JR to rupture in edge quite, achieves sees rank go up to all sorts of bolster plate of relevant data modulus of elasticity circularly. Can see clearly from which, the change of bolster plate can produce an effect to the service life of cutting tool. With hard metal photograph of former outfit bolster plate is compared, use steel bolster plate can improve average service life 176%(to see graph 3) . Contrary, the average service life that uses the bolster plate that nodular cast iron makes grey mouth decreased about 30% , and use multilayer black lead is cast-iron the bolster plate that makes makes service life rose 42% . The test that does for stuff place with EN-GJS 260 Gr is another kind of circumstance. Compare with photograph of steeliness bolster plate, no matter be the bolster plate that nodular cast iron makes (raise 330%) , multilayer still black lead is cast-iron the bolster plate that makes (raise 37%) , have clear advantage in service life respect (4) seeing a picture. Machine the individual extreme difference that cast-iron data appears on cutting tool service life, its part reason ascribes to the wave motion of result numerical value, consequently need continues to try approve. The result that these results and the turning test that early days does obtain forms contrast very hard, the phenomenon that because have one share,appears to contradict each other. All treatment need bolster plate to appear nevertheless the question that this still cannot answer pair of general and applicable first-rate flexibility. Ought to raise such question however, which kinds of flexibility to what kind of condition just be first-rate. For example, have all sorts of treatment process () of mill, car, and all sorts of workpiece material is done very hard compare each other, need to make judgement according to the result, different flexibility or bolster plate undertake adjustment according to corresponding treatment circumstance. The range of result wave motion of in use life test is very big, and also do not have general and applicable optimal flexibility, while this kind of trend asks to reducing interference factor, continue to have a test to the influence of flexibility. In the meantime, still raised a such question, simple change is made to flexibility on bolster plate foundation, whether can obtains result disappear inside fluctuant limits. WBK institute later dog research also makes clear, obtain a kind of possibility of relatively reliable result to depend on, design a kind of active milling head, the flexibility of this kind of milling head is OK stepless is adjusted, and can continue to enhance the result that we hope. For example, can imagine the cutting tool system of mechanical of a kind of hydraulic pressure, this system is in can contain at the back of dislocation razor blade the gasoline tank with an alterable pressure, gasoline tank can be changed flexibility and decrease brace up. CNC Milling CNC Machining