机械外文翻译中英文.doc

外文翻译--高速切削加工在模具制造中的新应用【中英文文献译文】

收藏

压缩包内文档预览:(预览前20页/共31页)
预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图 预览图
编号:51223800    类型:共享资源    大小:94.62KB    格式:ZIP    上传时间:2020-02-26 上传人:好资料QQ****51605 IP属地:江苏
12
积分
关 键 词:
中英文文献译文 外文 翻译 高速 切削 加工 模具 制造 中的 应用 中英文 文献 译文
资源描述:
外文翻译--高速切削加工在模具制造中的新应用【中英文文献译文】,中英文文献译文,外文,翻译,高速,切削,加工,模具,制造,中的,应用,中英文,文献,译文
内容简介:
附录附录1英文原文:High-speed cutting processing in mold manufacture applicationA.J.G. Nuttall *, G. LodewijksAbstractThe current mold application is widespread, also had the very big development with it related die making technology. At present, used the high-speed cutting production mold already to become the die making the general trend. In some mold Manufacturer, the high speed engine bed big area substitution electrical discharge machine, the high-speed cutting production mold already gradually became the die making the general trend. It can improve molds size, the shape and the surface roughness, reduces even omits the manual sharpening, thus reduces production cost and the reduction manufacturing cycle. This article through to the traditional mold processing craft and the high speed mold processing crafts contrast, elaborated the high-speed cutting processing superiority. In the article also briefly introduced the high-speed cutting processing in the processing craft aspect key technologies.Keywords High-speed cutting Grinding tool Grinding tool processing Process technology1 Introduction1.1 IntroductionAlong with the advance in technology and the industry swift development, the mold already became in the industrial production to use the extremely widespread main craft to equip now. The mold takes the important craft equipment, in Industry sectors and so on consumable, electric appliance electron, automobile, airplane manufacture holds the pivotal status. The manufactured products components rough machining 75%, the precision work 50% and the plastic parts 90% will complete by the mold. At present the Chinese mold market demand has reached 50,000,000,000 Yuan scales, our country die making market potential is huge. The mold is one kind of special-purpose tool, uses in forming () each metal or the nonmetallic material needs the components the shape product, this kind of special-purpose tool general designation mold. The mold is in the industrial production the most foundation equipment, is realizes the few cuttings and the non-cutting essential tool. The mold has widely used in the industrial production each domain, like the automobile, the motorcycle, the domestic electric appliances, the instrument, the measuring appliance, the electron and so on, in them 60%80% components need the mold to carry on the manufacture; The highly effective production in enormous quantitiess, bolt, nut and gasket standard letters and so on plastic also need the mold to produce; The engineering plastics, the powder metallurgy, the rubber, the alloy compression casting, the glass formation and so on need to use the mold to take shape.1.2 High-speed cutting process technologyAs the name suggests, the high-speed cutting, first is the high speed, namely must have the high spindle speed, for instance 12000r/min, 18000r/min, 30000r/min, 40000r/min, even also had a higher rotational speed still in the experiment; On the other hand, should also have the bigger to feed quantity, like 30000mm/min, 40000mm/min, even 60000mm/min; Has is after again the rapid traverse, trades fast the knife, the main axle trade the knife, from the static state arrives its needs rotational speed rise time and so on, only then achieved the above standards to be able to call it high speed.Next is must aim at the different processing object, the different degree of hardness, the different material quality, the different shape to choose the corresponding reasonable parameter, but cannot pursue constantly to be high speed and be high speed, regarding the die space processing, the shape is specially complex, but the cutting tool diameter is also small time, because cutting tools path is not the simple translation, but is the curve, even has right angle corner time, technological parameter rational especially important, if because wants to maintain the identical feed rate carries on the orthogonal cutting, will not be able to do well will cause as a result of the engine bed moving parts huge inertia the cutting tool will make when the bend angle movement to break suddenly, but the variable motion can, becauseMovements and so on acceleration and deceleration create the thickness of cutting the instantaneous change, but causes the cutter change to enable the work piece surface to have cuts, from this causes the processing drop in quality, therefore, in view of the different processing object, needs the programmers to choose the reasonable cutting tool path, optimized cutting parameter; On the other hand, according to needs to choose the suitable cutting velocity, only then can display the high-speed cutting truly like the strong point.The high-speed cutting (HSC) is an advanced technique of manufacture which for the past ten years rapidly rises. Because the high-speed cutting technology has the cutting efficiency to be high, the processing quality high, can process the hard steel stock and the good efficiency directly, causes profession and so on aviation, mold, automobile, light industry and information production efficiencies and the manufacture quality obviously enhances, and causes the processing craft and the equipment corresponding renewal. Therefore is similar to the numerical control technology is the same, the high-speed cutting and the high speed processing have become in the 21st century a machine-building industry influence profound technological revolution. At present, adapts the HSC request high speed machining center and other high speed numerically-controlled machine tool has assumed the popularization tendency in the developed country, our country recently is also speeding up the development.The high-speed cutting processing is faces for the 21st century a high technology and new technology, it is one kind is different with the traditional processing processing way. Compares with it, the high-speed cutting processing main axle rotational speed high, cuts high for the speed, the cutting quantity is small, but in the unit time material excises the quantity to increase 3 6 times actually. It take the high efficiency, the high accuracy and the high surface quality as the basic characteristic, in profession and so on in automobile industry, aerospace, mold manufacture and instrument measuring appliance has obtained the increasingly widespread application, and has obtained the significant technology economic efficiency, is the contemporary advanced manufacture technology important constituent. When with traditional way processing mold, often uses the electric spark machining, but the electrode design and makes itself is the technological process which time-consuming takes the trouble. But after uses the high-speed cutting processing, because the narrow and small region processing realization and the high grade superficial result, let the electrode the utilization ratio reduce greatly. Moreover, makes the electrode with the high speed mill also to be possible to make the production efficiency to enhance to a new scale. The major part mold may use the high-speed cutting technology to process, like the forging die, the compression casting mold, cast with the blow molding mold and so on. Hammers the cavity body shallowly, the cutting tool life is long; Compression casting mold size moderate, the productivity is high; Casts with the blow molding mold general size small, quite is economical. 2 the high-speed cutting processing mold relative tradition processes the mold the superiority 2.1 Enhances the productivity In the high-speed cutting the main axle rotational speed and enters for the speed enhancement, may enhance material removing rate. At the same time, thehigh-speed cutting may process the hard components, a many Cmmponents attipe clamps may complete thick, half essence and the precision work and so on the complete working procedure, also may meet the components surface quality requirements directly to the complex profile processing, therefore, the high-speed cutting craft often may save the electric spark Machining, manually rub repairs and so on the working procedure, reduces the craft route, then enhances the processing productivity greatly. The high-speed cutting processing permission use big to feed rate, enhances 510 times compared to the convention machining, the unit interval/unit time material excision rate may enhance 36 times, the process period may reduce greatly. This may use in processing needs to excise the metal massively the components, specially has the very vital significance regarding the aviation industry.2.2 Improvement processing precishon and surface qualhty The high rpeed engine bed must have high performance and so on rigidity and high accuracy, at the same time because cutting force low, the work piece thermal deformation reduces, the cutting tool distorts slightly, the high-speed cutting processing precision Is very high. Depth of cut small, but enters for the speed quickly, the processing surface roughness is very small, cuts when the aluminum alloy may reach Ra0.4 0.6, when cutting steel stock may reach Ra0.2 0.4.Compares with the conventional cutting, when high-speed cutting processing the cutting force may reduce 30% at least, this may reduce the processing regarding the processing rigidity bad components to distort, causes some thin wall class fine work piece the machining into possible. Because revolves high speed time the cutting tool cuts the excitation frequency is far away from the craft systems forced oscillation, has guaranteed the good processing condition. Because the cutting force is too small, cut the hot influence to be small, causes the cutting tool, the work piece distortion to be small, maintained the size accuracy, moreover also caused the friction between the cutting tool work piece changes is small, the cutting destruction level thinned, the residual stress was small, has realized the high accuracy, the low roughness processing.2.3 The reduced cutting produces quantity of heat Because the high-speed cutting processing is the shallow cutting, simultaneously the feed rate is very quick, the knife edge and the work piece contact length and the contact duration were short, reduced the knife edge and the work piece heat conduction, has avoided when the traditional processing met everywhere in the cutting tool and the work piece to have the big calorimetry shortcoming, guaranteed that the cutting tool worked under the temperature not high condition, lengthened cutting tools service life. As shown in Figure 1, A is time the high-speed cutting processing heat conduction process, B is the traditional processing heat conduction process. Fig.1 high speed processing and traditional processing heat conduction The high-speed cutting processing process is extremely rapid, 95% above cutting quantity of heat are extremely few, components not because the temperature rise will cause the warp or the inflation distortion. The high-speed cutting is suitable specially for the processing easy thermal deformation components. Is low regarding the processing melting point the metal which, easy to oxidize (for example magnesium), the high-speed cutting has certain significance.2.4 advantageoued in the processing thin wall components Time high-speed cuttings cutting force is small, has the high stability, but the high quality processes the thin wall components. Uses as shown in Figure 2 the lamination down milling the processing method, but high-speed cutting wall thickness 0.2mm, wall high 20mm thin wall components. This time, the knife edge and the work piece contact duration was short, has avoided the sidewall distortion.Figure.2 high-speed cutting thin wall components2.5 change the part substitutes certain crafts, like electric spark machining, abrasive machining and so onHigh strength and the high degree of hardnesss processing is also a high-speed cutting major characteristic, at present, the high-speed cutting has been possible the work hardness to reach HRC60 the components, therefore, the high-speed cutting can process after the heat treatment hardens the work piece. In the tradition processes in molds craft, before the precision work, hardens the work piece after the heat treatment to carry on the electric spark machining, may omit in the die making craft with the high-speed cutting processing substitution tradition cuttings processing method the electric spark machining, simplified the processing craft and the cost of investment.the molds size, the shape and the surface roughness are very important, if after processing the mold cannot meet the requirements the quality precision, needs the massive handworks to rub repairs the work, the handwork rubs repairs can obtain the good surface quality, but it will affect molds size and the shape precision. Therefore must omit as far as possible in the mold processing rubs manually repairs, improves the mold quality, reduces the production cost and the manufacturing cycle.Figure 3 is the traditional mold processing process: The semifinished materials - rough machining - semi-finishing - heat treatment hardens - the electric spark machining - precision work - to rub manually repairs. Figure 4 is the high speed mold processing process: Hardened semifinished materials - rough machining - semi-finishing - precision work.Figure.3 the traditional mold processes processFigure 4 the high speed mold processes processin Figure 4, in the high speed mold machining process reduced two technological processes, probably reduces the process period 30%50%. In the traditional processing crafts electric spark machining forms the hardened level easily in the melting processing surface layer, degree of hardness may reach 1000Hv, brings the difficulty for the following machining and the abrasive machining. The electric spark machining also easy to cause the surface layer fatigue cracking and cutting tools breakage.2.6 Economic efficiency remarkable enhancementSynthesis above all sorts of merits, namely: The comprehensive efficiency will improve, the quality enhances, the working procedure simplifies, the engine bed investment and the cutting tool investment as well as the maintenance cost increase and so on, will use the high-speed cutting craft to cause the synthesis economic efficiency remarkable enhancement. 3 high-speed cutting processing craft essential technologyThe high speed engine bed and the high speed cutter are the realization high-speed cutting premise and the basic condition, has the strict request in the high-speed cutting processing to the high speed engine bed performance and the cutting tool material choice. In order to realize the high-speed cutting processing, uses the high flexible high speed numerical control engine bed, the processing center generally, also some use special-purpose high speed mills, drilling machine. At the same time the engine bed has the high speed main axle to be systematic and the high rapid advance or progress gives the system, the high main axle rigidity characteristic, the high accuracy localization function and the high accuracy insert makes up the function, specially the circular arc high accuracy inserts makes up the function. The high-speed cutting cutting tool and ordinary processes the cutting tool the material to have is very greatly different. The main use cutting tool material has the hard alloy, the crystal combination diamond (PCD), the crystal combination cube boron nitride (PCBN) and the ceramics and so on. The high-speed cutting craft technology also is carries on the high-speed cutting processing the key. The cutting method chooses is improper, can make the cutting tool to intensify the attrition, cannot achieve the high speed processing completely the goal. The practice proved, if only then the high speed engine bed and the cutting tool but do not have the good craft technology to make the instruction, the expensive high-speed cutting processing equipment cannot fully play the role. The high-speed cutting processing craft essential technology mainly includes the cutting method and the cutting parameter choice optimization. a. Cutting way choise In the high-speed cutting processing, should select the down milling processing as far as possible, because in down milling time, the cutting tool just cut into the thickness of chip which the work piece produces to a big way, afterward reduces gradually. When up milling, the cutting tool just cut into the thickness of chip which the work piece produces to be smallest, afterward the accumulation, increased the cutting tool and the work piece friction like this gradually, has the big calorimetry on the knife edge, therefore produces in the up milling quantity of heat when down milling are more than, the radial force also greatly increases. Meanwhile in the down milling, the knife edge main compression stress, but when the up milling the knife edge tension stress, the stressful condition is bad, reduced cutting tools service life, the down milling and the up milling the cutting tool cuts into the work piece the process, as shown in Figure 5. Figure.5 the cutting tool cuts into the work piece the process hintb. Maintains constant metal removing rate The high-speed cutting processing is shallowly suitable for shallowly to cut the depth, the depth of cut should not surpass 0.2/ 0.2mm (ae/Ap), this is for avoids the cutting tool the position deviation, guarantees processes the mold the geometry precision. Maintains constant metal removing rate, guaranteed adds on the work piece the cutting load is constant, by obtains following several good processing effect: (1) may maintain constant cutting load; (2) may maintain the scrap size constant; (3) has the good hot shift; (4) the cutting tool and the work piece maintain at the cold condition; (5) does not need skilled to operate for the quantity and the main axle rotational speed; (6) may lengthen the cutting tool the life; (7) can guarantee the good processing quality and so on. c.choice of the Feeds way Regarding has opens the mouth die space the region, feeds as far as possible from material outside, by real-time analysis material cutting condition. But regarding does not have the die space enclosed area, selects the screw feed method, cuts into the local region.d. As far as possible reduced cutting tools commutation rapidlyReduces the cutting tool as far as possible the rapidly commutation, because the zigzag pattern mainly applies in the traditional processing, mainly chooses the return route or the sole way cutting in the high-speed cutting processing. This is because in commutation time the NC engine bed must stop (urgently changing down) immediately then the again execution next step of operation. As a result of engine bed acceleration limitation, but is easy to create the time the waste, stops anxiously or whips then can destroy the surface roughness, also has the possibility because has cut but produces the broach or in the outside undercut. Chooses the sole way cutting pattern to carry on the down milling, does not sever the cutting process and the cutting tool way as far as possible, reduces the cutting tool to cut into as far as possible cuts the number of times, by obtains the relatively stable cutting process. For example, in the cutting mold corner processing, the traditional processing method is uses the translation (G1), when the cutting tool cuts to the fillet place, the velocity of movement reduces speed, at the same time when enters for the commutation the cutting tool movement is not continuously, can have the massive friction and the quantity of heat in the intermittent process, if processes the aluminum alloy or other light metal alloys, produces the quantity of heat will damage the work piece surface quality. If uses the high-speed cutting processing the method, the use is smaller than the cutting mold corner radius cutting tool, the use high speed engine bed high accuracy circular arc inserts makes up the function (G2, G3) processes the mold corner, the high speed engine bed circular arc inserts makes up the movement is the continuous process, cannot have the cutting tool intermittent motion, thus reduced the cutting tool and the mold contact length and the time, avoids having the massive heat. e In Z direction cutting continual planeThe traditional processing die spaces method uses the profile milling, this processing way increased the cutting tool to cut into, to cut the work piece the number of times, has affected the work piece surface quality, has limited the engine bed and the cutting tool formidable function display. In the high-speed cutting processing, often uses the Z direction cutting continual plane. Uses step pitch which is smaller than the convention, thus reduces each tooth cutting elimination quantity, the improvement processing surfaces quality, reduced the process period.4 High-speed cutting process technology in die making applicationThe high-speed cutting process technology has a series of characteristics and the production benefit aspects great potential, already becomes country competition research and so on Germany, US and Japan important areas of technology. Now, US, Germany, Japan, France, Switzerland, Italy produce the different specifications each kind of commercialization high speed engine bed already entered the market, applies in the airplane, the automobile and the die making.Along with the high-speed cutting process technology introduction mold industry, has had the very tremendous influence to the traditional mold processing craft, changed the mold processing technical process. Because the mold profile is the very complex free surface generally, and degree of hardness is very high, uses conventional the machining method to satisfy the precision and the shape request with difficulty. The conventional processing method is after the annealing carries on the milling processing, then carries on the heat treatment, the grinding or the electric spark machining, finally the manual polish, polishing, cause the processing cycle to be very long like this. Specially the manual process period, must account for the entire processing cycle to be very big a part. HSC may achieve the accuracy requirement which the mold processes, reduced has even cancelled the manual processing, because and new cutting tool material (for example PCD, PCBN, cermet and so on) the appearance, HSC may the work hardness achieve HRC60, even degree of hardness higher work piece material, after might process hard mold, substitution electric spark machining and abrasive machining.The high speed milling processing has the highly effective high accuracy in the die making as well as may process the high hard material the merit, already obtained the widespread application in the industrially advanced country. The high-speed cutting process technology introduction mold industry, mainly applies in the following several aspects:1) hard mold die space direct processing. After using the high-speed cutting to be possible to process the hard material the characteristic direct processing hard mold die space, improved the quality which and the efficiency the mold processes, may substitute for the electric spark machining. (2) EDM (electric spark) electrode processing. Applied the high-speed cutting technology processing electrode to raise the electric spark machining efficiency to play the very major role. The high-speed cutting electrode improved electrodes surface quality and the precision, reduced the following working process.3) fast sample workpiece manufacture. Uses the high-speed cutting processing efficiency high characteristic, may use in processing the plastic and the aluminum alloy model. After the CAD design produces the 3D full-scale mockup fast, is higher than the fast prototype manufacture efficiency, the quality is good. (4) molds fast repair. The mold often needs to repair in the use process, lengthens the service life, in the past was mainly completes depending on the electrical finishing, now uses the high speed processing to be possible to complete this work quickly, moreover might use the original NC procedure, did not need to establish.Introduciton of MachiningHave a shape as a processing method, all machining process for the production of the most commonly used and most important method. Machining process is a process generated shape, in this process, Drivers device on the workpiece material to be in the form of chip removal. Although in some occasions, the workpiece under no circumstances, the use of mobile equipment to the processing, However, the majority of the machining is not only supporting the workpiece also supporting tools and equipment to complete.Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely on the shape of the structure, to a large extent, depend on effective in the form of raw materials. In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and structure of the production batch sizes are suitable for the original casting, Forging or pressure processing to produce, but usually prefer machining.Strict precision and good surface finish, Machining the second purpose is the establishment of the high precision and surface finish possible on the basis of. Many parts, if any other means of production belonging to the large-scale production, Well Machining is a low-tolerance and can meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing.Primary Cutting ParametersCutting the work piece and tool based on the basic relationship between the following four elements to fully describe : the tool geometry, cutting speed, feed rate, depth and penetration of a cutting tool.Cutting Tools must be of a suitable material to manufacture, it must be strong, tough, hard and wear-resistant. Tool geometry - to the tip plane and cutter angle characteristics - for each cutting process must be correct.Cutting speed is the cutting edge of work piece surface rate, it is inches per minute to show. In order to effectively processing, and cutting speed must adapt to the level of specific parts - with knives. Generally, the more hard work piece material, the lower the rate.Progressive Tool to speed iscut into the work piece speed. If the work piece or tool for rotating movement, feed rate per round over the number of inches to the measurement. When the work piece or tool for reciprocating movement and feed rate on each trip through the measurement of inches. Generally, in other conditions, feed rate and cutting speed is inversely proportional to。 Depth of penetration of a cutting tool - to inches dollars - is the tool to the work piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting chip thickness. Rough than finishing, deeper penetration of a cutting tool depth.Wears of Cutting ToolWe already have been processed and the rattle of the countless cracks edge tool, we learn that tool wear are basically three forms : flank wear, the former flank wear and V-Notch wear. Flank wear occurred in both the main blade occurred vice blade. On the main blade, shoulder removed because most metal chip mandate, which resulted in an increase cutting force and cutting temperature increase, If not allowed to check, That could lead to the work piece and the tool vibration and provide for efficient cutting conditions may no longer exist. Vice-bladed on, it is determined work piece dimensions and surface finish. Flank wear size of the possible failure of the product and surface finish are also inferior. In most actual cutting conditions, as the principal in the former first deputy flank before flank wear, wear arrival enough, Tool will be effective, the results are made unqualified parts.As Tool stress on the surface uneven, chip and flank before sliding contact zone between stress, in sliding contact the start of the largest, and in contact with the tail of zero, so abrasive wear in the region occurred. This is because the card cutting edge than the nearby settlements near the more serious wear, and bladed chip due to the vicinity of the former flank and lost contact wear lighter. This results from a certain distance from the cutting edge of the surface formed before the knife point Ma pit, which is usually considered before wear. Under normal circumstances, this is wear cross-sectional shape of an arc. In many instances and for the actual cutting conditions, the former flank wear compared to flank wear light, Therefore flank wear more generally as a tool failure of scale signs. But because many authors have said in the cutting speed of the increase, Maeto surface temperature than the knife surface temperatures have risen faster. but because any form of wear rate is essentially temperature changes by the significant impact. Therefore, the former usually wear in high-speed cutting happen.The main tool flank wear the tail is not processed with the work piece surface in contact, Therefore flank wear than wear along with the ends more visible, which is the most common. This is because the local effect, which is as rough on the surface has hardened layer, This effect is by cutting in front of the hardening of the work piece. Not just cutting, and as oxidation skin, the blade local high temperature will also cause this effect. This partial wear normally referred to as pit sexual wear, but occasionally it is very serious. Despite the emergence of the pits on the Cutting Tool nature is not meaningful impact, but often pits gradually become darker If cutting continued the case, then there cutter fracture crisis. If any form of sexual allowed to wear, eventually wear rate increase obviously will be a tool to destroy failure destruction, that will no longer tool for cutting, cause the work piece scrapped, it is good, can cause serious damage machine. For various carbide cutting tools and for the various types of wear, in the event of a serious lapse, on the tool that has reached the end of the life cycle. But for various high-speed steel cutting tools and wear belonging to the non-uniformity of wear, has been found : When the wear and even to allow for a serious lapse, the most meaningful is that the tool can re-mill use, of course, In practice, cutting the time to use than the short time lapse. Several phenomena are one tool serious lapse began features : the most common is the sudden increase cutting force, appeared on the work piece burning ring patterns and an increase in noise.The Effect of Changes in Cutting Parameters on Cutting TemperaturesIn metal cutting operations heat is generated in the primary and secondary deformation zones and this results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip.Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and cutting temperatures will reduce. When considering increase in undeformed chip thickness and cutting speed the situation is more comples. An increase in undeformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed, however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip in primary deformation. Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate, it is appropriate to indicate how cutting temperatures can be assessed from cutting data. The most direct and accurate method for measuring temperatures in high-speed-steel cutting tools is that of Wright&Trent which also yields detailed information on temperature distributions in high-speed-steel tools which relates microstructural changes to thermal history.Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructural changes srising from over tempering of the tempered martensitic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed-steel single point turning tools and twist drills.Automatic Fixture DesignAssembly equipment used in the traditional synchronous fixture put parts of the fixture mobile center, to ensure that components from transmission from the plane or equipment plate placed after removal has been scheduled for position. However, in certain applications, mobile mandatory parts of the center line, it may cause parts or equipment damage. When parts vulnerability and may lead to a small vibration abandoned, or when their location is by machine spindle or specific to die, Tolerance again or when the request is a sophisticated, it would rather let the fixture to adapt to the location of parts, and not the contrary. For these tasks, Elyria, Ohio, the company has developed Zaytran a general non-functional data synchronization West category FLEXIBILITY fixture. Fixture because of the interaction and synchronization devices is independent, The synchronous device can use sophisticated equipment to replace the slip without affecting the fixture force. Fixture specification range from 0.2 inches itinerary, 5 pounds clamping force of the six-inch trip, 400-inch clamping force.The characteristics of modern production is becoming smaller and smaller quantities and product specifications biggest changes. Therefore, in the final stages of production, assembly of production, quantity and product design changes appear to be particularly vulnerable. This situation is forcing many companies to make greater efforts to rationalize the extensive reform and the previously mentioned case of assembly automation. Despite flexible fixture behind the rapid development of flexible transport and handling devices, such as backward in the development of industrial robots, it is still expected to increase the flexibility fixture. In fact the important fixture devices - the production of the devices to strengthen investment on the fixture so that more flexibility in economic support holders. According to their flexibility and fixture can be divided into : special fixture, the fixture combinations, the standard fixture, high flexible fixture. Flexible fixture on different parts of their high adaptability and the few low-cost replacement for the characteristic. Forms can transform the structure of the flexible fixture can be installed with the change of structure components (such as needle cheek plate, Multi-chip components and flake cheek plate), a non-standard work piece gripper or clamping elements (for example : commencement standard with a clamping fixture and mobile components fixture supporting documents), or with ceramic or hardening of the intermediary substances (such as : Mobile particle bed fixture and heat fixture tight fixture). To production, the parts were secured fixture, the need to generate clamping function, its fixture with a few unrelated to the sexual submissive steps :According to the processing was part of that foundation and working characteristics to determine the work piece fixture in the required position, then need to select some stability flat combination, These constitute a stable plane was fixed in the work piece fixture set position on the clamp-profile structure, all balanced and torque, it has also ensured that the work features close to the work piece. Finally, it must be calculated and adjusted, assembly or disassembly be standard fixture components required for the position, so that the work piece firmly by clamping fixture in China. In accordance with this procedure, the outline fixture structure and equipped with the planning and recording process can be automated control.Structural modeling task is to produce some stable flat combination, Thus, these plane of the work pieces clamping force and will fixture stability. According to usual practice, this task can be human-machine dialogue that is almost completely automated way to completion. A man-machine dialogue that is automated fixture structure modeling to determine the merits can be conducted in an organized and planning fixture design, reduce the amount of the design, shortening the study period and better distribution of work conditions. In short, can be successfully achieved significantly improve fixture efficiency and effectiveness.Fully prepared to structure programs and the number of material circumstances, the completion of the first successful assembly can save up to 60% of the time.Therefore fixture process modeling agencies is the purpose of the program have appropriate documents. 5 ConclusionThe high-speed cutting processing uses the high cutting velocity and the feed rate, the small radial direction and the axial depth of cut, the cutting force is small, the processing surface roughness is very small, cutting tool life enhancement; With the high-speed cutting processing way substitution tradition processing way processing mold, might omit the electric spark machining and rub manually repairs, raised the productivity which the mold processed, reduced the production cost, reduced the processing cycle; When research high-speed cutting processing, must unify closely with the high-speed cutting processing technology, realizes the high efficiency, the high accuracy truly and the redundant reliable goal.The high-speed cutting process technology is the advanced technique of manufacture, has the broad application prospect. Replaces EDM with the high-speed cutting processing (or majority of replaces) speeds up the mold development speed, realizes the craft update major step. The promoted application high-speed cutting process technology applies in the mold manufacturing industry, not only may enhance the machine-finishing large scale the efficiency, the quality, reduces the cost, moreover may lead a series of high technology and new technology industry the development. Therefore, current strengthens the high-speed cutting technology the basic research, establishes the high-speed cutting database, the high-speed cutting safety work standard, enhances the engine bed and tool profession development innovation ability, speeds up the high-speed cutting cutting tool system, the high-speed cutting engine bed systems research development and the industrial production, already was the urgent matter.References1 A.C. Low, J.W. Kyle, Grinding tool technology recent development, The Mechanical Engineers Association, London, 1986. High-speed cutting and grinding tool manufacture2 K.L. Johnson, High-speed cutting and grinding tool manufacture, Cambridge University Press, Cambridge, 1985.3 W.DMay, E.L. Morris, D. Atack, new using of Cutting technology, Applied Physics 30 (1959) 17131724.4 S.C. Hunter, Grinding tool manufacture, Applied Mechanics 28 (1961) 611617.5 G. Lodewijks, Dynamics of Belt Systems, Thesis, Delft University of Technology, Delft, 1995.6 A.N. Gent, High-speed cutting outline, Carl Hanser Verslag, 2001.中文翻译高速切削加工在模具制造中的新应用A.J.G. Nuttall *, G. Lodewijks摘要当前模具应用广泛,与之相关的模具制造技术也有了很大的发展。目前,采用高速切削生产模具已经成为模具制造的大趋势。在一些模具生产厂家,高速机床大面积取代电火花机床,高速切削生产模具已经逐渐成为模具制造的大趋势。它能改善模具的尺寸、形状和表面粗糙度,减少甚至省去手工修磨,从而降低生产成本和缩短制造周期。本文通过对传统模具加工工艺和高速模具加工工艺的对比,阐述了高速切削加工的优势。文中还简要介绍了高速切削加工在加工工艺方面的关键技术。关键字 高速切削;磨具;磨具加工;加工技术1 绪论1.1 引言随着科技进步和工业的飞速发展,模具已经成为当今工业生产中使用极为广泛的主要工艺装备。模具作为重要的工艺装备,在消费品、电器电子、汽车、飞机制造等工业部门中占有举足轻重的地位。工业产品零件粗加工的75%,精加工的50%及塑料零件的90%将由模具完成。目前中国模具市场需求已达500亿元的规模,我国模具制造市场潜力巨大。模具是一种专用工具,用于成形(型)各种金属或非金属材料所需要零件的形状制品,这种专用工具统称模具。模具是工业生产中最基础的设备,是实现少切削和无切削的不可缺少的工具。模具已广泛用于工业生产中的各个领域,如汽车、摩托车、家用电器、仪器、仪表、电子等,它们中60%80%的零件都需要模具来进行制造;高效大批量生产的塑料件、螺钉、螺母和垫圈等标准件也需要模具来生产;工程塑料、粉末冶金、橡胶、合金压铸、玻璃成型等更需要用模具来成型。 1.2 高速切削加工技术概述顾名思义,高速切削,首先是高的速度,即要有高的主轴转速,比如12000r/min、18000r/min、30000r/min、40000r/min,甚至还有更高的转速仍在试验中;另一方面,又应有更大的进给量,如30000mm/min、40000mm/min,甚至60000mm/min;再有就是快速移动、快速换刀、主轴换刀后从静态到达其所需转速的加速时间等等,只有达到了上述标准才能称之为高速。 其次是要针对不同的加工对象、不同的硬度、不同的材质、不同的形状来选择相应合理的参数,而不能一味地追求为高速而高速,特别是对于型腔加工,形状复杂而刀具直径又较小时,由于刀具的运动轨迹不是简单的直线运动而是曲线,甚至有直角拐弯的时候,工艺参数的合理性就尤为重要,因为要想保持同一进给速度进行直角切削,搞不好会由于机床运动部件的巨大惯性而导致刀具做弯角运动时突然断裂,而变速运动又会由于加速和减速等运动造成切削厚度的瞬间变化,而导致切削刀变化使工件表面有切纹,由此使加工质量下降,所以,针对不同的加工对象,需要编程人员选择合理的刀具运动轨迹,优化切削参数;另一方面,根据需要选择适合的切削速度,只有这样才能真正发挥高速切削的长处。高速切削(HSC)是近十年来迅速崛起的一项先进制造技术。由于高速切削技术具有切削效率高、加工质量高、能直接加工淬硬钢件和良好的经济性,使航空、模具、汽车、轻工和信息等行业的生产效率与制造质量显著提高,并引起加工工艺及装备相应的更新换代。因此如同数控技术一样,高速切削和高速加工已成为21世纪机械制造业一场影响深远的技术革命。目前,适应HSC要求的高速加工中心和其他高速数控机床在发达国家已呈普及趋势,我国近来也在加快发展。 高速切削加工是面向21世纪的一项高新技术,它是一种不同于传统加工的加工方式。与之相比,高速切削加工主轴转速高、切削进给速度高、切削量小,但单位时间内的材料切除量却增加36倍。它以高效率、高精度和高表面质量为基本特征,在汽车工业、航空航天、模具制造和仪器仪表等行业中获得了愈来愈广泛的应用,并已取得了重大的技术经济效益,是当代先进制造技术的重要组成部分。 用传统方式加工模具时,常采用电火花加工,但电极的设计与制造本身是一个费时费力的工艺过程。而采用高速切削加工后,由于狭小区域加工的实现和高质量的表面结果,让电极的使用率大大降低。另外,用高速铣来制造电极也可以使生产效率提高到一个新的档次。 绝大部分模具均可利用高速切削技术来加工,如锻模、压铸模、注塑与吹塑模等。锻模腔体较浅,刀具寿命较长;压铸模尺寸适中,生产率较高;注塑与吹塑模一般尺寸较小,比较经济。 2 高速切削加工模具相对传统加工模具的优势 2.1 提高生产率 高速切削中主轴转速和进给速度的提高,可提高材料去除率。同时,高速切削可加工淬硬零件,许多零件一次装夹可完成粗、半精和精加工等全部工序,对复杂型面加工也可直接达到零件表面质量要求,因此,高速切削工艺往往可省却电火花加工、手工磨修等工序,缩短工艺路线,进而大大提高加工生产率。 高速切削加工允许使用较大的进给率,比常规切削加工提高510倍,单位时间材料切除率可提高36倍,加工时间可大大减少。这样可以用于加工需要大量切除金属的零件,特别是对于航空工业具有十分重要的意义。 2.2 改善加工精度和表面质量 高速机床必须具备高刚性和高精度等性能,同时由于切削力低,工件热变形减少,刀具变形小,高速切削的加工精度很高。切削深度较小,而进给速度较快,加工表面粗糙度很小,切削铝合金时可达Ra0.40.6,切削钢件时可达Ra0.20.4。 和常规切削相比,高速切削加工时切削力至少可降低30%,这对于加工刚性较差的零件来说可减少加工变形,使一些薄壁类精细工件的切削加工成为可能。因为高速旋转时刀具切削的激励频率远离工艺系统的受迫振动,保证了较好的加工状态。由于切削力太小,切削热影响小,使得刀具、工件变形小,保持了尺寸的精确性,另外也使得刀具工件间的摩擦变小,切削破坏层变薄,残余应力小,实现了高精度、低粗糙度加工。2.3减少切削产生的热量 因为高速切削加工是浅切削,同时进给速度很快,刀刃和工件的接触长度和接触时间非常短,减少了刀刃和工件的热传导,避免了传统加工时在刀具和工件接触处产生大量热的缺点,保证刀具在温度不高的条件下工作,延长了刀具的使用寿命。如图1所示,A为高速切削加工时的热传导过程,B为传统加工的热传导过程。图1 高速加工和传统加工的热传导高速切削加工过程极为迅速,95%以上的切削热量极少,零件不会由于温升导致翘曲或膨胀变形。高速切削特别适用于加工容易热变形的零件。对于加工熔点较低、易氧化的金属(如镁),高速切削有一定意义。2.4 有利于加工薄壁零件 高速切削时的切削力小,有较高的稳定性,可高质量地加工出薄壁零件。采用如图2所示分层顺铣的加工方法,可高速切削出壁厚0.2mm,壁高20mm的薄壁零件。此时,刀刃和工件的接触时间非常短,避免了侧壁的变形。 图2 高速切削薄壁零件2.5可部分替代某些工艺,如电火花加工、磨削加工等 高强度和高硬度的加工也是高速切削的一大特点,目前,高速切削已可加工硬度达HRC60的零件,因此,高速切削能够加工经热处理硬化后的工件。在传统加工模具的工艺中,精加工前对热处理硬化后的工件需进行电火花加工,用高速切削加工替代传统切削的加工方法可以省去模具制造工艺中的电火花加工,简化了加工工艺和投资成本。模具的尺寸、形状和表面粗糙度很重要,如果加工后的模具不能达到要求的质量精度,就需要大量的手工磨修工作,手工磨修能够得到较好的表面质量,但是它会影响模具的尺寸和形状精度。因此在模具加工还要尽量省去手工磨修,以提高模具质量,降低生产成本和制造周期。图3为传统模具加工过程:毛坯粗加工半精加工热处理硬化电火花加工精加工手工磨修。 图4为高速模具加工过程:硬化的毛坯粗加工半精加工精加工在,图4所示的高速模具切削加工过程中减少了两个工艺过程,大约缩短加工时间30%50%。传统加工工艺中的电火花加工容易在熔化的加工表层形成硬化层,硬度可达1000Hv,给后面的切削加工和磨削加工带来困难。电火花加工还容易引起表层疲劳裂纹和刀具的破损。 图3传统模具加工的过程图4 高速模具加工的过程2.6经济效益显著提高 综合上述种种优点,即:综合效率提高、质量提高、工序简化、机床投资和刀具投资以及维护费用增加等,采用高速切削工艺将使综合经济效益显著提高。 3 高速切削加工工艺关键技术高速机床和高速刀具是实现高速切削的前提和基本条件,在高速切削加工中对高速机床的性能和刀具材料的选择有严格的要求。 为了实现高速切削加工,一般采用高柔性的高速数控机床、加工中心,也有的采用专用的高速铣、钻床。机床同时具有高速主轴系统和高速进给系统,高的主轴刚度特性,高精度定位功能和高精度插补功能,特别是圆弧高精度插补功能。 高速切削刀具与普通加工刀具的材料有很大不同。主要使用的刀具材料有硬质合金、聚晶金刚石(PCD)、聚晶立方氮化硼(PCBN)和陶瓷等。 高速切削的工艺技术也是进行高速切削加工的关键。切削方法选择不当,会使刀具加剧磨损,完全达不到高速加工的目的。实践证明,如果只有高速机床和刀具而没有良好的工艺技术作指导,昂贵的高速切削加工设备也不能充分发挥作用。高速切削加工工艺关键技术主要包括切削方法和切削参数选择的优化。 A切削方式的选择 在高速切削加工中,应尽量选用顺铣加工,因为在顺铣时,刀具刚切入工件产生的切屑厚度为最大,随后逐渐减小。在逆铣时,刀具刚切入工件产生的切屑厚度为最小,随后逐渐增厚,这样增加了刀具与工件的摩擦,在刀刃上产生大量热,所以在逆铣中产生的热量比在顺铣时多很多,径向力也大大增加。同时在顺铣中,刀刃主要受压应力,而在逆铣中刀刃受拉应力,受力状态较恶劣,降低了刀具的使用寿命,顺铣和逆铣时刀具切入工件的过程,如图5所示。图5 刀具切入工件的过程示意B保持恒定的金属去除率 高速切削加工适于浅的切深,切削深度不应超过0.2/0.2mm(ae/ap),这是为避免刀具的位置偏差,确保加工模具的几何精度。保持恒定的金属去除率,保证加在工件上的切削载荷是恒定的,以获得下面几点好的加工效果:(1)可保持的恒定切削负载;(2)可保持切屑尺寸的恒定;(3)有较好的热转移;(4)刀具和工件均保持在较冷的状态;(5)不必熟练操作进给量和主轴转速;(6)可延长刀具的寿命;(7)能保证较好的加工质量等。 C走刀方式的选择 对于带有敞口型腔的区域,尽量从材料的外面走刀,以实时分析材料的切削状况。而对于没有型腔的封闭区域,采用螺旋进刀方式,在局部区域切入。 D 尽量减少刀具的急速换向 尽量减少刀具的急速换向,由于之字形模式主要应用于传统加工,在高速切削加工中主要选择回路或单一路径切削。这是因为在换向时NC机床必须立即停止(紧急降速)然后再执行下一步操作。由于机床的加速局限性,而容易造成时间的浪费,急停或急动则会破坏表面精度,且有可能因为过切而产生拉刀或在外拐角处咬边。选择单一路径切削模式来进行顺铣,尽可能地不中断切削过程和刀具路径,尽量减少刀具的切入切出次数,以获得相对稳定的切削过程。 例如,在切削模具拐角的加工中,传统的加工方法是采用直线运动(G1),当刀具切削到圆角处时,运动速度减慢,同时在进给换向时刀具的运动是不连续,在间歇的过程中会产生大量摩擦和热量,如果加工铝合金或其他轻合金,产生的热量将损坏工件表面质量。 如果使用高速切削加工的方法,使用小于切削模具拐角半径的刀具,利用高速机床高精度的圆弧插补功能(G2、G3)加工模具拐角,高速机床圆弧插补运动是连续过程,不会产生刀具的间歇运动,从而减少了刀具与模具接触长度和时间,避免产生大量的热。 E 在Z方向切削连续的平面 传统加工型腔的方法是使用靠模铣削,这种加工方式增加了刀具切入、切出工件的次数,影响了工件的表面质量,限制了机床和刀具强大功能的发挥。在高速切削加工中,常采用Z方向切削连续的平面。采用比常规小的步距,从而降低每齿切削去除量,改善的加工表面的质量,缩短了加工时间。 4 快速切削加工技术在模具制造中的应用 高速切削加工技术所具有的一系列特色和生产效益方面的巨大潜力,早已成为德、美、日等国竞相研究的重要技术领域。如今,美、德、日、法、瑞士、意大利生产的不同规格的各种商业化高速机床已经进入市场,应用于飞机、汽车及模具制造。 随着高速切削加工技术引进模具工业,对传统的模具加工工艺产生了很大的影响,改变了模具加工工艺流程。由于模具型面一般都是十分复杂的自由曲面,并且硬度很高,采用常规的切削加工方法难以满足精度和形状要求。常规的加工方法是在退火后进行铣削加工,然后进行热处理、磨削或电火花加工,最后手工打磨、抛光,这样使得加工周期很长。特别是手工加工时间,要占整个加工周期很大一部分。HSC可以达到模具加工的精度要求,减少甚至取消了手工加工,并且由于新型刀具材料(如PCD、PCBN、金属陶瓷等)的出现,HSC可以加工硬度
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
提示  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
关于本文
本文标题:外文翻译--高速切削加工在模具制造中的新应用【中英文文献译文】
链接地址:https://www.renrendoc.com/p-51223800.html

官方联系方式

2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   
关于我们 - 网站声明 - 网站地图 - 资源地图 - 友情链接 - 网站客服 - 联系我们

网站客服QQ:2881952447     

copyright@ 2020-2025  renrendoc.com 人人文库版权所有   联系电话:400-852-1180

备案号:蜀ICP备2022000484号-2       经营许可证: 川B2-20220663       公网安备川公网安备: 51019002004831号

本站为文档C2C交易模式,即用户上传的文档直接被用户下载,本站只是中间服务平台,本站所有文档下载所得的收益归上传人(含作者)所有。人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。若文档所含内容侵犯了您的版权或隐私,请立即通知人人文库网,我们立即给予删除!