The high speed processing technique that contemporary mould makes

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1.

Foreword mould serves as important tooling, make in electron of consumable, electric equipment, car, plane the place that hold the balance is had in waiting for industrial industry. Although in recent years technology of our country mould had rapid development, but as bigger than still having as photograph of production powerful nation difference. The mould with at present inferior content of our country technology already supply exceeds demand, and nicety, mixed high-grade pattern relies on an entrance in great quantities. Raising a mould to produce technical level and quality is the main factor that develops manufacturing industry of our country mould. Because use technology of cutting of mould high speed to be able to raise a mould to produce efficiency and mould precision and service life apparently, because this is replacing mould of electric spark finish machining gradually, already was made by foreign mould the enterprise is used generally, become the big climate that the mould creates. But technology of high speed cutting is compared in time of the application in mould production short, and demand of in use technology is higher, company of production of our country major mould still cannot master and apply, down to cannot produce an advantage. Article lieutenant general emphasizes cutting of introductory high speed to machine the problem of a few practical technologies of the mould and application. 2.

The advantage that application of high speed cutting machines at the mould and the characteristic that the problem pattern that shows level to need to solve machines are odd form of a small lot, geometry is complex, because this machines cycle to grow, manufacturing efficiency is low. In conventional mould treatment technology, strong pattern of finish machining temper by dipping in water uses electric spark treatment and technology of artificial Xiu Guang normally, later period treatment spent a large number of time. Shorten handling time and the main goal that reducing manufacturing cost is development mould processing technique. In recent years, the mould machined craft respect to have a lot of new technologies, if design of high speed cutting, CAD/CAE is emulated, processing of milling of fast and archetypal patternmaking, electric spark and compound treatment, among them the most conspicuous, effect is best is treatment of high speed cutting. Mould of treatment of high speed cutting is the high rotate speed that uses a machine tool and tall feed speed, complete the many production process of the mould with cutting means. Main show is in the advantage of mould of treatment of high speed cutting the following respects: Rough machining of cutting of ① high speed and semifinishing machining, raise metallic excision rate greatly. ② uses machine tool of high speed cutting, cutting tool and technology, can process oil hard data. To small-sized mould, after material heat treatment, thick, finish machining can be installed in finish in clip; To large mould, in the rough machining before heat treatment and semifinishing machining, the finish machining after heat treatment temper by dipping in water is hard. Hard cutting of high accuracy of ③ high speed replaces smooth full treatment, the handiwork that reduces a large number of costing is repaired grind, than electric spark treatment raises efficiency 50% . Treatment of ④ hard cutting shapes finally the surface, raise precision of exterior quality, appearance (not only exterior surface roughness is low, and exterior brightness is tall) , the mould treatment that is used at complex curved surface has an advantage more. ⑤ avoided electric spark and the decarbonization that grinding produces, burn and micro-crack appearance, reduced the exterior loss after mould finish machining greatly, improve mould life 20% . ⑥ workpiece is calorific force of little, cutting is reduced, heat is out of shape small, combinative CAD/CAM technology is used at machining electrode quickly, especially figure is complex, small wall kind easy metabolic electrode. The appeal that the advantage of high speed cutting machines to the mould is self-evident, but meanwhile, tall, tall to the use requirement of cutting tool, need has the finished cost of high speed cutting of the mould technology of sophisticated computer process designing does support, equipment to run cost tall, accordingly, wait for the reason of the respect as a result of capital, technology, the application that home processes a mould to high speed cutting is not much still, at present earnestly needs to solve cutting tool of cutting of the machine tool that how choose and uses high speed to machine a mould, high speed, reasonable treatment a series of problems such as layer of process designing of contrail of craft, cutting tool and craft experiment. 3.

The high speed that the machine tool of high speed cutting that machines a mould chooses to use at mould of high speed cutting should note the following problem when the machine tool: (1) power of main shaft of requirement machine tool big, rotate speed is high, satisfy thick, finish machining. Finish machining mould should use small diameter cutting tool, main shaft rotate speed achieves 15000 ~ 20000rmp above. Main shaft rotate speed can undertake rough machining and semifinishing machining in the machine tool under 10000rpm. If need to satisfy thick, finish machining at the same time in large mould production, what choose a machine tool to had better have the main shaft of two kinds of rotate speed, or the electric main shaft of two kinds of norms. (2) the machine tool is fast feed is not quite tall to requirement of quick idle stroke. But should have higher treatment feed rate (30 ~ 60m/min) and add decelerate high to spend. (3) have good high speed, high accuracy to control a system, the function such as control of control of the look up before having high accuracy interpolation, outline, position of tall acceleration, high accuracy. (4) choose the CAD/CAM software with form a complete set of high speed machine tool, use at the software of mould of high speed cutting especially. In mould production the application of 5 axes machine tool increases gradually, cooperate high speed cutting to machine a mould to have the following advantage: ① can change point of view of cutting tool cutting, cutting condition is good, reduce cutting tool to wear away, be helpful for protecting cutting tool and prolong cutting tool life; ② treatment course is agile, reduce cutting tool interference, can machine the pattern with exterior mixed figure and deep antrum mould; ③ size range of pipe bent is big, suit a variety of type moulds to machine. 5 axes machine tool has workbench type and milling head type normally 5 axes machine tool two kinds, can undertake choosing in the light of mould type. Milling head type in 5 axes machine tool, can change milling head and change the thick, precision work that the 5 axes machine tool of head of electric main shaft can use at the mould respectively. 4.

The treatment of cutting of high speed of cutting tool technology of mould of high speed cutting needs to provide appropriate cutting tool. Cutting tool of hard alloy coating, get together the application that brilliant enhances cutting tool of pottery and porcelain makes the matrix that cutting tool holds the blade department that has tall hardness and tall tenacity concurrently at the same time becomes a possibility, promoted the development that high speed machines. Get together nitrogen of brilliant cubic metre changes boron (PCBN) the hardness of bit can amount to 3500 ~ 4500HV, get together brilliant diamond (PCD) hardness can amount to 6000 ~ 10000HV. In recent years, 3 water chestnut of German SCS, Japan (divine steel) reach friendly, Switzerland Shanteweike, United States agrees the company of foreign famous cutting tool such as Na Feishuo rolls out cutting tool of respective high speed cutting early or late, cutting of not only high speed is common the cutting tool of structural steel, the cutting tool of pottery and porcelain that still has hard steel of temper by dipping in water of cutting of direct high speed exceed strong cutting tool, especially coating cutting tool is producing tremendous effect in the semifinishing machining of hard steel of temper by dipping in water and finish machining. At present domestic high speed machines the development of cutting tool and abroad to still have bigger difference, and the main factor that the high price that imports cutting tool also becomes mould of cutting of block up high speed to apply. Generally speaking, when requirement cutting tool and the acceleration that the knife places achieve 3g above, the radial of cutting tool is jumpy should be less than 0.

015mm, and 4 times what the length of the knife is not more than cutting tool diameter. According to the actual count of SANDVIK company, titanium is changed in use carbon nitrogen (TiCN) the integral hard alloy of coating establishs milling cutter (58HRC) when undertaking high speed milling, linear velocity of rough machining cutting tool is 100m/min about, and when finish machining and superfinishing, linear velocity exceeded 280m/min. According to the experience of mould of finish machining of domestic high speed, when using milling cutter of head of small diameter ball to have mould precision work, linear velocity exceeded 400m/min. Material of this pair of cutting tool (include hardness, tenacity, red rigid) , cutting tool appearance (include to discharge precision of bits function, surface, dynamic balancing the gender) and cutting tool life has very high demand. Accordingly, when mould of finish machining of high speed hard cutting, want to choose the machine tool of high rate not only, and must reasonable choose cutting tool and cutting technology. When high speed machines a mould, want to note the following respects mainly: ① machines an object according to what differ, CBN and cutting tool of cutting tool of coating of logical choice hard alloy, diamond agglomeration layer. ② uses milling cutter of head of small diameter ball to have mould outside precision work, normally 10mm of < of diameter of finish machining cutting tool. The basis is machined material and hardness, chooses cutting tool diameter is different also. In cutting tool material choose a side, tiAIN exceeds cutting tool of coating of fine grain hard alloy lubricant condition is good, when cutting mould steel, having is better than cutting tool of coating of TiCN hard alloy fight abrasiveness can. ③ chooses appropriate cutting tool parameter, wait like the horn before losing. Concussion tenacity is fought when high speed machines cutting tool to ask Biputongjia is versed in capability of taller, heatproof concussion is stronger. ④ adopts a variety of methods to improve cutting tool life, wait like means of appropriate feed, feed, lubricant means, in order to reduce cutting tool cost. ⑤ uses high speed knife handle. Application is at present most is HSK knife handle and cutting tool of clip of hot press fitting, the integral dynamic balancing that system of the main shaft after noticing cutting tool holds clip answers in the meantime. 5.

In the technology of mould of treatment of engineering technology high speed of mould of high speed cutting, engineering technology is the crucial factor that cooperates machine tool and cutting tool to use. Will look with the situation that at present domestic mould produces, engineering technology had restricted high speed to process the application of the mould greatly. Because the time of application of high speed treatment is shorter,be on one hand, had not formed what mature quite, the craft system of systematization and standard; It is craft of high speed cutting on the other hand experiment cost is high, need invests bigger fund and longer time. Engineering technology of mould of high speed cutting basically includes: (1) the discovery when the experiment of craft of mould of high speed cutting that is aimed at different material is consulting milling of foreign high speed machines the craft parameter of the spare parts, the cutting tool that foreign company manufactures is a basis import data standard will do a test, when using the parameter that its recommend to machine homebred material mould in high speed, effect difference is more apparent. Accordingly, use abroad cutting tool, besides the parameter that need consults manufacturer is offerred, real craft test also is necessary. Domestic tool manufacturer recommends the technical parameter of high speed milling rarely, because this chooses homebred cutting tool more be necessary to do a test, in order to obtain more satisfactory craft parameter. Had better choose the cutting tool that secures manufacturer home, pass a test, form processing technique standard, optimize the treatment craft parameter that gives to fit this business on this foundation, bring into industry standard. (2) means of method of the cutting tool in the method of treatment cutting tool of high speed cutting and engineering technology of mould of cutting of process designing high speed, feed and feed are main content. Processing techniques of a lot of cutting tool method in engineering technology of mould of high speed cutting are to reduce cutting tool to wear away, prolong cutting tool service life, because this cutting tool is in,the contrail in feed of high speed cutting compares common treatment complex much. High speed machines mould craft processing to should follow the following principle: When ① uses precision work of small diameter cutting tool, cutting speed is reduced as the addition of material hardness. ② carries relatively smooth feed and feed rate, cutting load is successive, reduce mutation, delay is retreated into delay. Avoid direct and perpendicular be down feed and bring about collapse blade: The milling force of diagonal contrail feed is increased gradually, small to the concussion of cutting tool and main shaft, can reduce collapse blade apparently; Feed of screw type contrail is cut, suit more model the high speed treatment of antrum mould. Cutting of grain of ③ small feed, penknife. Normally feed is less than milling cutter diameter 10% , feed width is less than milling cutter diameter 40% . ④ withholds surplus of even finish machining. ⑤ maintains odd blade cutting. According to afore-mentioned regulation, the feed way way that uses normally has the following kinds: ① prevents the milling exercise of straight corner as far as possible; Turning point uses cutting of corkscrewed yarn feed, those who carry cutting load is smooth. ② shuns work as far as possible the feed outside and the motion that retreat a knife, enter next deepness from outline directly. Use however inclined to gradually feed is cut or corkscrewed yarn is cut. ③ is constant every blade feed, machine plane with corkscrewed yarn or cycloidal method feed, and maintain odd blade cutting. Aperture adds man-hour to use feed of milling high speed to finish, can improve exterior quality not only, and can prolong cutting tool life. When ④ outline is machined, maintain go up in horizontal (contour line) , every feed deepness is identical. When entering next deepness, gradually feed is cut. When ⑤ machines the lesser size shape such as groove, choose a diameter to be less than the cutting tool of shape size, with corkscrewed yarn or cycloidal method feed, maintain odd blade cutting. The cutting tool method that uses in moulds of these high speed cutting handles strategy to need process designing implementation, difficulty of too complex method handiwork process designing and workload are very big, the application of technology of mould of high speed cutting was affected on certain level, because this is best,can come true through software of automatic process designing. Finish machining of high speed cutting raises a requirement to the process designing of CAM, software of automatic process designing needs to get used to production timely roll out. Delcam company began high speed cutting to machine the research of process designing technology a few years ago, developed high speed cutting PowerMILL of module of software of automatic process designing; The MasterCAM company that mould treatment makes dosage the biggest also developed high speed cutting module of software of HSM of automatic process designing. Pass module of these software of automatic process designing, the processing technique of method of high speed cutting that preamble place mentions all can come true. At present domestic software company also is developing high speed cutting module of software of automatic process designing. 6.

The choice that HSM of Lv of take an examination and EDM return when high speed machines the other technology of the mould and example high speed to machine a mould, dry cutting and lubricant refrigeration reach safety to wait for a problem. (1) the general principle that has choosing to high speed cutting and electric spark treatment is: Treatment tall hardness, small diameter, pointed horn, narrow electric spark machine tool is used when groove, specific parameter can make judgement according to circumstance of the technology of each enterprise and equipment. For example the example of a treatment that Delcam provides is used 1.

The cutting tool treatment of 6mm diameter is narrow groove, cutting parameter is: Rotate speed 40000rpm, cutting deepness 0.

1mm, feed speed 30m/min. (2) when die of high speed cutting provides data, use it is lubricant and OK that proper refrigeration is mixed reduce cutting tool to wear away, improve exterior quality. But the cutting tool that is used at high speed hard cutting fights thermal shock ability to differ mostly, because cutting of this high speed uses dry cutting or minim oil more,mist lubricates. (3) what cutting tool wears away and destroy still should consider to monitor when mould of high speed cutting, the safe problem such as bit connective intensity. And use treatment of general accuracy machine tool to differ, the to machine tool and cutting tool close check before safety defends and switching on the mobile phone is very serious to high speed cutting. 7.

Epilogue mould market has strong demand to high speed treatment, domestic pattern company and research unit had obtained a few result, gained a few experience. Fizzle out for example some mould factory uses cliff zone mould of large car tire wins the precision work of machine tool of high speed finish machining that Nanjing quarto company produces better effect. But mould of high speed treatment uses time in our country shorter, applied foundation is poorer, lack mature experience, integral technology level is not high, progress is slow, still exist in high speed machine tool and cutting tool application and treatment craft respect a lot of problems, need is produced learn to grind union, increase investment, integrated each field force drives high speed cutting to make medium application in the mould. CNC Milling