Technology of high speed cutting

One, overview from 20 centuries 30 time Germany Dr. Carl Salomon advances idea of high speed cutting first since, through the mechanism of 50 time and feasibility research, the engineering technology of 70 time studies, the technology of high speed cutting of comprehensive system studies 80 time, arrive at the beginning of 90 time, technology of high speed cutting begins to enter practical change, to 90 time later period, machine tool of cutting of commercial high speed is many emerge in large numbers, at the beginning of 21 centuries, technology of high speed cutting gets applied generally in industrial developed country, making the mainstream technology that cutting machines. International produced the basis 1992 project seminar (the definition that theme of CIRP) annual meeting reports, high speed cutting shows cutting speed exceeds traditional cutting rate normally 5 - the cutting treatment of 10 times. Accordingly, according to processing data what differ and machine means is different, the cutting speed limits of high speed cutting is different also. High speed cutting includes bore of turning of high speed milling, high speed, high speed and mill of high speed car to wait, but majority application is high speed milling. Current, treatment aluminium alloy already was achieved 2000 - 7500m/min; Cast-iron for 900 - 5000m/min; Steel is 600 - 3000m/min; Nickel radical alloy amounts to heat-resisting 500m/min; Titanium alloy is amounted to 150 - 1000m/min; Fiber increases plastic for 2000 - 9000m/min. High speed cutting is technology of a system, affect the each respect factor of high speed technology, the enterprise needs fibrous root occupies the material of the product and structural characteristic, purchase machine tool of appropriate high speed cutting, choose appropriate cutting cutting tool, use first-rate cutting technology, machine the effect in order to reach ideal high speed. 2, the characteristic of high speed cutting and applied practice make clear, high speed cutting has characteristic of the following treatment: Cutting force reduces workpiece heat to be out of shape reduce the dimension that is helpful for assuring a spare parts, form precision already machined vibration of exterior quality tall machining complex to reduce what raise material excision to lead finished cost to reduce high speed cutting significantly afore-mentioned characteristics, mirrorred in its inside applicable domain, can satisfy the demand with efficiency, quality and higher and higher cost, in the meantime, solved appearance of three-dimensional curved surface efficient nicety machines a problem, it is hard data and Bao Bi treatment offerred new solution. High speed cutting receives wider and wider application in the domain such as industry of industry of aerospace industry, mould, electron, auto industry. In aerospace if owner solves purify of material of spare parts large surplus, Bao Bi the problem such as material of treatment, high accuracy, difficult treatment and treatment efficiency, especially cutting of high speed of integral structural member, assured spare parts quality already, leave out a lot of ship-fitter are made; Mould of the much in mould course of study all technology of milling of applicable high speed, high speed hard cutting can machine hardness to amount to 50 - the oil hard data of 60HRC, replaced treatment of partial electric spark consequently, reduced benchwork to write grinding work order, shortened mould treatment is periodic; Black lead of high speed milling can obtain the electric spark of high quality to machine electrode. Of high speed cutting efficient make its presswork in the electron circuit board stiletto and car get applied extensively in mass production. Current, the workpiece stuff that fits high speed cutting has hard steel of alloy of aluminium alloy, titanium, copper alloy, stainless steel, temper by dipping in water, black lead and vycor to wait. 3, cutting of high speed of machine tool of high speed cutting should achieve favorable applied result, must mix the machine tool of high-powered high speed cutting, cutting tool that suits with workpiece data phase to specific treatment photograph of engineering technology of object first-rate treatment is united in wedlock. Machine tool of high speed cutting is the postulate that high speed cutting applies. The main shaft rotate speed of high speed milling machine is in commonly 18, 000rpm above, 30, 000 - 60, 000rpm applies actually in industry already also, power is in ten to a few tile, make known to lower levels of high speed condition arrives most high-power, but torque falls the smallest, at the same time allowable milling cutter diameter also will be reduced. Speed of straight job feed is in the feed drive of tall trends commonly 20 - 40m/min, the drive rate that uses linear electric machinery is in 60 - 120m/min, acceleration 1 - 2g. Circumgyrate workbench speed can amount to 360rmp, circumgyrate acceleration amounts to 47 ° / S² , 5 coordinate linkage machines basic contented high speed. Machine tool main shaft and lathe bed should have good tigidity, admirable suction brace up character and heat proof quality. Scagliola lathe bed has very tall thermal stability, good suction brace up function, can make the most reasonable machine tool structure according to need. The suction that considers to make clear a scagliola brace up the gender is cast-iron 6 times the left and right sides. Graph the CNC control system that CNC of machine tool of 1 high speed controls a technology to have capacity of fast data processing is high speed machine tool is necessary assure. Graph the 1 concerned skill that showed CNC of high speed machine tool controls a system. The technology, technology such as high capacity memory and ETH-ERNET communication is being inspected before is the foundation of speed of expensive data processing, NURBS curve interpolation offerred short block and smooth interpolation solution for complex curved surface, digital drive overcame imitate to control the time lag problem of minim, technology of high resolution feedback is the safeguard that high accuracy machines. In addition, the safety of the machine tool defends, the cooling and the knife library amount, speed that change a knife, lubricant, ability that discharge bits is waited a moment, also be the serious problem that design or machine tool of high speed of choose and buy must consider. 4, cutting tool of cutting of high speed of technology of cutting tool of high speed cutting compares groovy treatment to have higher demand in durability and dependability respect not only, there also is special demand in the security aspect of cutting tool system. From raise durability and dependability angle, need consideration: Cutting tool matrix and number of edge of structure of geometry of coating material point of a knife and arbor extend quantity cutting dosage to walk along cutting tool of condition of knife means refrigeration and workpiece material to match from increase use security respect, need consideration: The clip of intensity of cutting tool system and dimension arbor and machine tool holds dynamic balancing of cutting tool of means of clamp of means razor blade to pursue because high speed cutting is tall,2 cutting tool spread the effect that measures pair of durability the characteristic such as rotate speed and fast feed, besides the material of advanced cutting tool of good wearability and tall intensity tenacity, technology of good cutting tool coating, reasonable geometrical structure parameter and tall homocentric outside the element such as spent edge precision quality, still require special attention the other element influence to cutting tool durability. Graph 2 extend a quantity to be opposite for different cutting tool the influence of cutting method length, reach a capacity it is thus clear that shorter, durability is taller. Usually, the durability prep above of suitable mill goes against mill, and the durability lowest of mill of move back and forth (3) seeing a picture. Graph 3 in enter real report cutting tool to carrying feed direction feed on the head downward, and to aspirant report cutting tool is pulling feed direction feed, also have bigger effect to durability. Milling of aluminium alloy high speed uses double blade milling cutter normally, overmuch edge can reduce the space that hold bit, cause easily cut bits to stick a knife. For escape resonance frequency, also can use 3 blade milling cutter in order to increase percussion frequency. Aluminium alloy treatment produces the tumor that accumulate bits easily, this is very harmful to high speed milling. Want to reduce the generation of the tumour that accumulate bits, cutting tool surface wants flowing; Avoid to use deposit of physical gas phase (PVD) coating cutting tool, because TiAlN coating produces chemical reaction very easily with aluminium, can choose blame coating cutting tool, coating of fine brilliant diamond or kind diamond coating cutting tool; Be like likely, use the Leng Jin inside oily mist cutting tool as far as possible travel is cooling and lubricant. Graph different milling means is opposite knife of iron of 3 balls head the structure of cutting tool of milling of influence high speed of durability all has very big effect to cutting tool durability and security, crucial point includes the balance of cutting tool system to design; Reduce radial and axial to beat; Control dynamic balancing precision; Use knife handle of short awl of HSK knife handle or similar and double-faced contact generally with machine tool connection; The clamp of cutting tool is newest the trend is to use cold shrink type clamp structure (or call shrinkage fitting type) , induction or sirocco are used to heat when holding clip make arbor aperture expands, take out old cutting tool, load new cutting tool, use wind next cold make cutting tool cools room temperature, use arbor aperture and cutting tool external diameter be filled with too cooperate clamp, the radial of cutting tool of this kind of structure is jumpy in 4µm, tigidity is tall, dynamic balancing sex is good, clamping force is large, high rotate speed falls to still can maintain high clamp reliability, special the treatment of high speed milling that applies to higher rotate speed. 5, craft of cutting of high speed of engineering technology of high speed cutting basically includes: The treatment that suits high speed cutting takes knife kind, special CAD/CAM process designing is politic, optimized high speed machines parameter, the cooling kind that sufficient refrigeration lubricates and has environmental protection character is waited a moment. The treatment means in principle of high speed cutting is used more statified annulus cuts treatment. Direct and perpendicular be down feed to appear extremely easily collapse blade phenomenon, unfavorable use. The milling power of means of diagonal contrail feed is increased gradually, because this is right,the concussion of cutting tool and main shaft is compared perpendicular next knives are small, can reduce the phenomenon of blade of collapse leaving a sword apparently. Means of feed of screw type contrail uses helix to be cut downward, suit most model the need that antrum high speed machines. Principle of CAD/CAM process designing is the cutting tool load that keeps constant as far as possible, fall change of the rate that take a form to lowest, make program processing speed the biggest change. Main method has: Reduce program block as far as possible, raise a program to treat rate; The person can be added in block a few circular arc transfer paragraph, reduce the sharp change of speed as far as possible; Rough machining is not simple purify stuff, want to notice to make sure this working procedure and mental allowance of follow-up working procedure are even, reduce the variation of milling bear as far as possible; Use more statified suitable mill means; Cut and cut use successive helix and circular arc contrail to undertake as far as possible tangential feed, in order to assure constant cutting condition; Make full use of the function of the emulation test and verify that numerical control system offers. The spare parts must be passed before treatment emulate, the validity that digit of knife of ① of test and verify occupies, ② cutting tool whether is each place interfered with spare parts happening, whether do ③ cutting tool and clamping apparatus accessory produce collision, ensure product quality and safety in operation. Quality of surface of the efficiency of treatment of affirmatory and main consideration of dosage of treatment of high speed milling, treatment, cutting tool wears away and finished cost. When different cutting tool processes different workpiece data, treatment dosage can have very big difference, still do not have complete treatment data at present. Normally, as cutting speed rise, treatment efficiency rises, cutting tool wears away aggravate, outside dividing taller every tine feed, treatment surface surface roughness rises along with cutting speed and reduce. To cutting tool life, every tine feed and axial are cut all put greatly in optimal value, and the limits of optimal value is opposite narrower. The choice principle with general parameter of high speed milling is high cutting rate, medium every tine feed Fz, lesser axial is cut deep Ap and proper big radial cuts deep Ae. The addition with heat in metal cutting is led as a result of metallic purify when high speed milling, cold cut medium to must be had will cut bits to rush quickly from workpiece, reduce heat in metal cutting and the capacity that increase cutting interface to lubricate. Groovy cooling fluid and add note means to enter treatment area very hard, can increase milling cutter sword instead cutting the temperature that cuts a course to change, generation heats up exhaustion, reduce cutting tool life and reliability. Material of contemporary cutting tool, wait like cutting tool of hard alloy, coating, pottery and porcelain and cermet, CBN have taller red rigid, if insoluble heat is fatigue problem, can not use cooling fluid. Refrigeration of minim oily mist can reduce cutting tool on one hand - cut bits - the attrition between workpiece, petty oily mist particle is fast when surface of cutting tool of bring into contact with on the other hand the heat exchange effect of aerification relatively the pattern of heat exchange effect that cooling fluid heat conducts can take away more quantity of heat, already made the cooling medium of first selection of high speed cutting at present. Medium of refrigeration of nitrogen oily mist obtained very good result in the high speed milling in titanium alloy. Cooling medium divides nitrogen oily mist outside the cooling and lubricant effect that has air oily fog, still have fight oxidation to wear away wait for action, when the milling rate of 33m/min, compare refrigeration of air oily mist, cutting tool durability rises 60% , milling force can be reduced 20% - 30% . 6, cutting of epilogue high speed is advanced, the integrated technology that developing, must mix the machine tool of high-powered high speed cutting, cutting tool that suits with workpiece data phase to specific treatment photograph of engineering technology of object first-rate treatment is united in wedlock, produce the advantage of technology of high speed cutting adequately. Technology of tool of high speed cutting also is a crucial technology, to suit and promote the development of technology of cutting of our country high speed, we should realise adequately, the tool makes the trade that is content of a hi-tech, the basic research that should strengthen this domain, project studies and use research; The huge of technology of high speed cutting that develops quickly spurs the demand of high-powered cutting tool, industry of our country tool should be mixed in the wearability of cutting tool, precision mainly dependability respect enhances strength of research and development, increase the competitive capacity of cutting tool; The competition ability of cutting tool should be in centrally high-powered brought macroeconomic benefit, in application domain promotion uses high-powered cutting tool; Provide personalized technology service; According to our country's current actual condition, proposal key develops coating technology (like wear-resisting (hard, soft) the) such as coating of structure of rice of coating, compound coating, accept, cutting tool quality ensures technology and cutting tool database. CNC Milling