High-speed milling
本文《High-speed milling》為一篇留學(xué)生dissertation翻譯,英國dissertation網(wǎng)在此提供中英文的對照參考。全文就高速銑削的相關(guān)問題進(jìn)行了研究分析,由本站專業(yè)導(dǎo)師進(jìn)行潤色修飾,讓文章語句更顯精煉。
High-speed machining is an advanced manufacturing technology, different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, mold manufacturing and instrumentation industry, such as access to a wide range of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs.
1 One of the advantages of high-speed machining
High-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. In conventional machining in a series of problems has plagued by high-speed machining of the application have been resolved.
1.1 Increase productivity
High-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reduced by 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processing productivity and competitiveness of products in the market.
1.2 Improve processing accuracy and surface quality
High-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low, the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when up Ra0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um.
1.3 Cutting reduce the heat
Because the main axis milling machine high-speed rotation, cutting a shallow cutting, and feed very quickly, and the blade length of the workpiece contacts and contact time is very short, a decrease of blades and parts of the heat conduction. High-speed cutting by dry milling or oil cooked up absolute (mist) lubrication system, to avoid the traditional processing tool in contact with the workpiece and a lot of shortcomings to ensure that the tool is not high temperature under the conditions of work, extended tool life.#p#分頁標(biāo)題#e#
1.4 This is conducive to processing thin-walled parts
High-speed cutting of small cutting force, a higher degree of stability, Machinable with high-quality employees compared to the company may be very good, but other than the company's employees may Suanbu Le outstanding work performance. For our China practice, we use the models to determine the method of staff training needs are simple and effective. This study models can be an external object, it can also be a combination of internal and external. We must first clear strategy for the development of enterprises. Through the internal and external business environment and organizational resources, such as analysis, the future development of a clear business goals and operational priorities. According to the business development strategy can be compared to find the business models, through a comparative analysis of the finalization of business models. In determining business models, a, is the understanding of its development strategy, or its market share and market growth rate, or the staff of the situation, and so on, according to the companies to determine the actual situation. As enterprises in different period of development, its focus is different, which means that enterprises need to invest the manpower and financial resources the focus is different. So in a certain period of time, enterprises should accurately selected their business models compared with the departments and posts, so more practical significance, because the business models are not always good, but to compare some aspects did not have much practical significance, Furthermore This can more fully concentrate on the business use of limited resources. Identify business models, and then take the enterprise of the corresponding departments and staff with the business models for comparison, the two can be found in the performance gap, a comparative analysis to find reasons, in accordance with this business reality, the final identification of training needs. The cost of training is needed, if not through an effective way to determine whether companies need to train and the training of the way, but blind to training, such training is difficult to achieve the desired results. A comparison only difference between this model is simple and practical training.
1.5 Can be part of some alternative technology, such as EDM, grinding high intensity and high hardness processing
High-speed cutting a major feature of high-speed cutting machine has the hardness of HRC60 parts. With the use of coated carbide cutter mold processing, directly to the installation of a hardened tool steel processing forming, effectively avoid the installation of several parts of the fixture error and improve the parts of the geometric location accuracy. In the mold of traditional processing, heat treatment hardening of the workpiece required EDM, high-speed machining replace the traditional method of cutting the processing, manufacturing process possible to omit die in EDM, simplifying the processing technology and investment costs . #p#分頁標(biāo)題#e#
High-speed milling in the precincts of CNC machine tools, or for processing centre, also in the installation of high-speed spindle on the general machine tools. The latter not only has the processing capacity of general machine tools, but also for high-speed milling, a decrease of investment in equipment, machine tools increased flexibility. Cutting high-speed processing can improve the efficiency, quality improvement, streamline processes, investment and machine tool investment and maintenance costs rise, but comprehensive, can significantly increase economic efficiency.
2 High-speed milling
High-speed milling the main technical high-speed cutting technology is cutting the development direction of one of it with CNC technology, microelectronic technology, new materials and new technology, such as technology development to a higher level. High-speed machine tools and high-speed tool to achieve high-speed cutting is the prerequisite and basic conditions, in high-speed machining in the performance of high-speed machine tool material of choice and there are strict requirements.
2.1 High-speed milling machine in order to achieve high-speed machining
General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:
General use of highly flexible high-speed CNC machine tools, machining centers, and some use a dedicated high-speed milling, drilling. At the same time a high-speed machine tool spindle system and high-speed feeding system, high stiffness of the main characteristics of high-precision targeting and high-precision interpolation functions, especially high-precision arc interpolation function. High-speed machining systems of the machine a higher demand, mainly in the following areas:
High-speed milling machine must have a high-speed spindle, the spindle speed is generally 10000 ~ 100000 m / min, power greater than 15 kW. But also with rapid speed or in designated spots fast-stopping performance. The main axial space not more than 0 .0 0 0 2 m m. Often using high-speed spindle-hydrostatic bearings, air pressure-bearing, mixed ceramic bearings, magnetic bearing structure of the form. Spindle cooling general use within the water or air cooled.
High-speed processing machine-driven system should be able to provide 40 ~ 60 m / min of the feed rate, with good acceleration characteristics, can provide 0.4 m/s2 to 10 m/s2 acceleration and deceleration. In order to obtain good processing quality, high-speed cutting machines must have a high enough stiffness. Machine bed material used gray iron, can also add a high-damping base of concrete, to prevent cutting tool chatter affect the quality of processing. A high-speed data transfer rate, can automatically increase slowdown. Processing technology to improve the processing and cutting tool life. At present high-speed machine tool manufacturers, usually in the general machine tools on low speed, the feed of the rough and then proceed to heat treatment, the last in the high-speed machine on the half-finished and finished, in improving the accuracy and efficiency at the same time, as far as possible to reduce processing Cost.#p#分頁標(biāo)題#e#
2.2 High-speed machining tool
High-speed machining tool is the most active one of the important factors, it has a direct impact on the efficiency of processing, manufacturing costs and product processing and accuracy. Tool in high-speed processing to bear high temperature, high pressure, friction, shock and vibration, such as loading, its hardness and wear-resistance, strength and toughness, heat resistance, technology and economic performance of the basic high-speed processing performance is the key One of the factors. High-speed cutting tool technology development speed, the more applications such as diamond (PCD), cubic boron nitride (CBN), ceramic knives, carbide coating, (C) titanium nitride Carbide TIC (N) And so on. CBN has high hardness, abrasion resistance and the extremely good thermal conductivity, and iron group elements between the great inertia, in 1300 ℃ would not have happened significant role in the chemical, also has a good stability. The experiments show that with CBN cutting tool
HRC35 ~ 67 hardness of hardened steel can achieve very high speed. Ceramics have good wear resistance and thermal chemical stability, its hardness, toughness below the CBN, can be used for processing hardness of HRC <5 0 parts. Carbide Tool good wear resistance, but the hardness than the low-CBN and ceramics. Coating technology used knives, cutting tools can improve hardness and cutting the rate, for cutting HRC40 ~ 50 in hardness between the workpiece. Can be used to heat-resistant alloys, titanium alloys, hightemperature alloy, cast iron, Chungang, aluminum and composite materials of high-speed cutting Cut, the most widely used. Precision machining non-ferrous metals or non-metallic materials, or the choice of polycrystalline diamond Gang-coated tool.
2.3 High-speed processing technology
High-speed cutting technology for high-speed machining is the key. Cutting Methods misconduct, will increase wear tool to less than high-speed processing purposes. Only high-speed machine tool and not a good guide technology, high-speed machining equipment can not fully play its role. In high-speed machining, should be chosen with milling, when the milling cutter involvement with the workpiece chip thickness as the greatest, and then gradually decreased. High-speed machining suitable for shallow depth of cut, cutting depth of not more than 0.2 mm, to avoid the location of deviation tool to ensure that the geometric precision machining parts. Ensure that the workpiece on the cutting constant load, to get good processing quality. Cutting a single high-speed milling path-cutting mode, try not to interrupt the process and cutting tool path, reducing the involvement tool to cut the number to be relatively stable cutting process. Tool to reduce the rapid change to, in other words when the NC machine tools must cease immediately, or Jiangsu, and then implement the next step. As the machine tool acceleration restrictions, easy to cause a waste of time, and exigency stop or radical move would damage the surface accuracy. In the mold of high-speed finishing, in each Cut, cut to the workpiece, the feed should try to change the direction of a curve or arc adapter, avoid a straight line adapter to maintain the smooth process of cutting.#p#分頁標(biāo)題#e#
3 Die in high-speed milling processing of
Milling as a highly efficient high-speed cutting of the new method,in
Mould Manufacturing has been widely used. Forging links in the regular production model, with EDM cavity to be 12 ~ 15 h, electrodes produced 2 h. Milling after the switch to high-speed, high-speed milling cutter on the hardness of HRC 6 0 hardened tool steel processing. The forging die processing only 3 h20min, improve work efficiency four to five times the processing surface roughness of Ra0.5 ~ 0.6m, fully in line with quality requirements.
High-speed cutting technology is cutting technology one of the major developments, mainly used in automobile industry and die industry, particularly in the processing complex surface, the workpiece itself or knives rigid requirements of the higher processing areas, is a range of advanced processing technology The integration, high efficiency and high quality for the people respected. It not only involves high-speed processing technology, but also including high-speed processing machine tools, numerical control system, high-speed cutting tools and CAD / CAM technology. Die-processing technology has been developed in the mold of the manufacturing sector in general, and in my application and the application of the standards have yet to be improved, because of its traditional processing with unparalleled advantages, the future will continue to be an inevitable development of processing technology Direction.
4 Numerical control technology and equipping development trend and countermeasure
Equip the engineering level, level of determining the whole national economy of the modernized degree and modernized degree of industry, numerical control technology is it develop new developing new high-tech industry and most advanced industry to equip (such as information technology and his industry, biotechnology and his industry, aviation, spaceflight, etc. national defense industry) last technology and getting more basic most equipment. Marx has ever said "the differences of different economic times, do not lie in what is produced, and lie in how to produce, produce with some means of labor ". Manufacturing technology and equipping the most basic means of production that are that the mankind produced the activity, and numerical control technology is nowadays advanced manufacturing technology and equips the most central technology. Nowadays the manufacturing industry all around the world adopts numerical control technology extensively, in order to improve manufacturing capacity and level, improve the adaptive capacity and competitive power to the changeable market of the trends. In addition every industrially developed country in the world also classifies the technology and numerical control equipment of numerical control as the strategic materials of the country, not merely take the great measure to develop one's own numerical control technology and industry, and implement blockading and restrictive policy to our country in view of " high-grade, precision and advanced key technology of numerical control " and equipping. In a word, develop the advanced manufacturing technology taking numerical control technology as the core and already become every world developed country and accelerate economic development in a more cost-effective manner, important way to improve the overall national strength and national position. #p#分頁標(biāo)題#e#
Numerical control technology is the technology controlled to mechanical movement and working course with digital information, integrated products of electromechanics that the numerical control equipment is the new technology represented by numerical control technology forms to the manufacture industry of the tradition and infiltration of the new developing manufacturing industry, namely the so-called digitization is equipped, its technological range covers a lot of fields: (1)Mechanical manufacturing technology; (2)Information processing, processing, transmission technology; (3)Automatic control technology; (4)Servo drive technology; (5)Technology of the sensor; (6)Software engineering ,etc..
Development trend of a numerical control technology
The application of numerical control technology has not only brought the revolutionary change to manufacturing industry of the tradition, make the manufacturing industry become the industrialized symbol , and with the constant development of numerical control technology and enlargement of the application, the development of some important trades (IT , automobile , light industry , medical treatment ,etc. ) to the national economy and the people's livelihood of his plays a more and more important role, because the digitization that these trades needed to equip has already been the main trend of modern development. Numerical control technology in the world at present and equipping the development trend to see, there is the following several respect [1- ] in its main research focus.
5 A high-speed, high finish machining technology and new trend equipped
The efficiency, quality are subjavanufacturing technology. High-speed, high finish machining technology can raise the efficiency greatly , improve the quality and grade of the products, shorten production cycle and improve the market competitive power. Japan carries the technological research association first to classify it as one of the 5 great modern manufacturing technologies for this, learn (CIRP) to confirm it as the centre in the 21st century and study one of the directions in international production engineering.
In the field of car industry, produce one second when beat such as production of 300,000 / vehicle per year, and many variety process it is car that equip key problem that must be solved one of; In the fields of aviation and aerospace industry, spare parts of its processing are mostly the thin wall and thin muscle, rigidity is very bad, the material is aluminium or aluminium alloy, only in a situation that cut the speed and cut strength very small high, could process these muscles, walls. Adopt large-scale whole aluminium alloy method that blank " pay empty " make the wing recently, such large-scale parts as the fuselage ,etc. come to substitute a lot of parts to assemble through numerous rivet , screw and other connection way, make the intensity , rigidity and dependability of the component improved. All these, to processing and equipping the demand which has proposed high-speed, high precise and high flexibility. #p#分頁標(biāo)題#e#
According to EMO2001 exhibition situation, high-speed machining center is it give speed can reach 80m/min is even high , air transport competent speed can up to 100m/min to be about to enter. A lot of automobile factories in the world at present, including Shanghai General Motors Corporation of our country, have already adopted and substituted and made the lathe up with the production line part that the high-speed machining center makes up. HyperMach lathe of U.S.A. CINCINNATI Company enters to nearly biggest 60m/min of speed, it is 100m/min to be fast, the acceleration reaches 2g, the rotational speed of the main shaft has already reached 60 000r/min. Processing a thin wall of plane parts, spend 30min only, and same part general at a high speed milling machine process and take 3h, the ordinary milling machine is being processed to need 8h; The speed and acceleration of main shaft of dual main shaft lathes of Germany DMG Company are up to 120000r/mm and 1g.
In machining accuracy, the past 10 years, ordinary progression accuse of machining accuracy of lathe bring 5μm up to from 10μm already, accurate grades of machining center from 3~5μm, rise to 1~1.5μm, and ultraprecision machining accuracy is it enter nanometer grade to begin already (0.01μm).
In dependability, MTBF value of the foreign numerical control device has already reached above 6 000h, MTBF value of the servo system reaches above 30000h, demonstrate very high dependability .
In order to realize high-speed, high finish machining, if the part of function related to it is electric main shaft, straight line electrical machinery get fast development, the application is expanded further .
5.2 Link and process and compound to process the fast development of the lathe in 5 axes
Adopt 5 axles to link the processing of the three-dimensional curved surface part, can cut with the best geometry form of the cutter , not only highly polished, but also efficiency improves by a large margin . It is generally acknowledged, the efficiency of an 5 axle gear beds can equal 2 3 axle gear beds, is it wait for to use the cubic nitrogen boron the milling cutter of ultra hard material is milled and pared at a high speed while quenching the hard steel part, 5 axles link and process 3 constant axles to link and process and give play to higher benefit. Because such reasons as complicated that 5 axles link the numerical control system , host computer structure that but go over, it is several times higher that its price links the numerical control lathe than 3 axles , in addition the technological degree of difficulty of programming is relatively great, have restricted the development of 5 axle gear beds.
At present because of electric appearance of main shaft, is it realize 5 axle complex main shaft hair structure processed to link greatly simplify to make, it makes degree of difficulty and reducing by a large margin of the cost, the price disparity of the numerical control system shrinks. So promoted 5 axle gear beds of head of complex main shaft and compound to process the development of the lathe (process the lathe including 5). #p#分頁標(biāo)題#e#
At EMO2001 exhibition, new Japanese 5 of worker machine process lathe adopt complex main shaft hair, can realize the processing of 4 vertical planes and processing of the wanton angle, make 5 times process and 5 axles are processed and can be realized on the same lathe, can also realize the inclined plane and pour the processing of the hole of awls. Germany DMG Company exhibits the DMUVoution series machining center, but put and insert and put processing and 5 axles 5 times to link and process in once, can be controlled by CNC system or CAD/CAM is controlled directly or indirectly.
5.3 Become the main trend of systematic development of contemporary numerical control intelligently, openly, networkedly.
The numerical control equipment in the 21st century will be sure the intelligent system, the intelligent content includes all respects in the numerical control system: It is intelligent in order to pursue the efficiency of processing and process quality, control such as the self-adaptation of the processing course, the craft parameter is produced automatically; Join the convenient one in order to improve the performance of urging and use intelligently, if feedforward control , adaptive operation , electrical machinery of parameter , discern load select models , since exactly makes etc. automatically; The ones that simplified programming , simplified operating aspect are intelligent, for instance intelligent automatic programming , intelligent man-machine interface ,etc.; There are content of intelligence diagnose , intelligent monitoring , diagnosis convenient to be systematic and maintaining ,etc..
Produce the existing problem for the industrialization of solving the traditional numerical control system sealing and numerical control application software. A lot of countries carry on research to the open numerical control system at present, such as NGC of U.S.A. (The Next Generation Work-Station/Machine Control), OSACA of European Community (Open System Architecture for Control within Automation Systems), OSEC (Open System Environment for Controller) of Japan, ONC (Open Numerical Control System) of China, etc.. The numerical control system melts to become the future way of the numerical control system open. The so-called open numerical control system is the development of the numerical control system can be on unified operation platform, face the lathe producer and end user, through changing, increasing or cutting out the structure target(numerical control function), form the serration, and can use users specially conveniently and the technical know-how is integrated in the control system, realize the open numerical control system of different variety , different grade fast, form leading brand products with distinct distinction. System structure norm of the open numerical control system at present, communication norm , disposing norm , operation platform , numerical control systematic function storehouse and numerical control systematic function software development ,etc. are the core of present research. #p#分頁標(biāo)題#e#
The networked numerical control equipment is a new light spot of the fair of the internationally famous lathe in the past two years. Meeting production line , manufacture system , demand for the information integration of manufacturing company networkedly greatly of numerical control equipment, realize new manufacture mode such as quick make , fictitious enterprise , basic Entrance that the whole world make too. Some domestic and international famous numerical control lathes and systematic manufacturing companies of numerical control have all introduced relevant new concepts and protons of a machine in the past two years, if in EMO2001 exhibition, " Cyber Production Center " that the company exhibits of mountain rugged campstool gram in Japan (Mazak) (intellectual central production control unit, abbreviated as CPC); The lathe company of Japanese big Wei (Okuma ) exhibits " IT plaza " (the information technology square , is abbreviated as IT square ); Open Manufacturing Environment that the company exhibits of German Siemens (Siemens ) (open the manufacturing environment, abbreviated as OME),etc., have reflected numerical control machine tooling to the development trend of networked direction.
5.4 Pay attention to the new technical standard, normal setting-up
5.4.1 Design the norm of developing about the numerical control system
As noted previously, there are better common ability, flexibility, adaptability, expanding in the open numerical control system, such countries as U.S.A. ,European Community and Japan ,etc. implement the strategic development plan one after another , carry on the research and formulation of the systematic norm (OMAC , OSACA , OSEC ) of numerical control of the open system structure, 3 biggest economies in the world have carried on the formulation that nearly the same science planned and standardized in a short time, have indicated a new arrival of period of change of numerical control technology. Our country started the research and formulation of standardizing the frame of ONC numerical control system of China too in 2000.
5.4.2 About the numerical control standard
The numerical control standard is a kind of trend of information-based development of manufacturing industry. Information exchange among 50 years after numerical control technology was born was all because of ISO6983 standard, namely adopt G, M code describes how processes, its essential characteristic faces the processing course, obviously, he can't meet high-speed development of modern numerical control technology's needs more and more already. For this reason, studying and making a kind of new CNC system standard ISO14649 (STEP-NC) in the world, its purpose is to offer a kind of neutral mechanism not depending on the concrete system, can describe the unified data model in cycle of whole life of the products, thus realize the whole manufacture process, standardization of and even each industrial field product information.
The appearance of STEP-NC may be a revolution of the technological field of the numerical control, on the development and even the whole manufacturing industry of numerical control technology, will exert a far-reaching influence. First of all, STEP-NC puts forward a kind of brand-new manufacture idea, in the traditional manufacture idea, NC processes the procedures to all concentrate on individual computer. Under the new standard, NC procedure can be dispersed on Internet, this is exactly a direction of open , networked development of numerical control technology. Secondly, STEP-NC numerical control system can also reduce and process the drawing (about 75%), process the procedure to work out the time (about 35%) and process the time (about 50%) greatly. #p#分頁標(biāo)題#e#
At present, American-European countries pay much attention to the research of STEP-NC, Europe initiates IMS plan (1999.1.1-2001.12.3) of STEP-NC. 20 CAD/CAM/CAPP/CNC users, manufacturers and academic organizations from Europe and Japan participated in this plan. STEP Tools Company of U.S.A. is a developer of the data interchange software of manufacturing industry in the global range, he has already developed the super model (Super Model ) which accuses of information exchange of machine tooling by counting, its goal is to describe all processing courses with the unified norm. Such new data interchange form has already been verified in allocating the SIEMENS, FIDIA and European OSACA-NC numerical control at present.
6 pairs of basic estimations of technology and industry development of numerical control of our country
The technology of numerical control of our country started in 1958, the development course in the past 50 years can roughly be divided into 3 stages: The first stage is from 1958 to 1979, namely closed developing stage. In this stages, because technology of foreign countries blockade and basic restriction of terms of our country, the development of numerical control technology is comparatively slow. During "Sixth Five-Year Plan Period" , " the Seventh Five-Year Plan Period " of the country in second stage and earlier stage in " the Eighth Five-Year Plan Period ", namely introduce technology, digest and assimilate, the stage of establishing the system of production domesticization arisesing tentatively. At this stage , because of reform and opening-up and national attention , and study the improvement of the development environment and international environment, research , development and all making considerable progress in production domesticization of the products of the technology of numerical control of our country. The third stage is and during the "Ninth Five-Year Plan Period" on the later stage in "the Eighth Five-Year Plan Period" of the country, namely implement the research of industrialization, enter market competition stage. At this stage, made substantive progress in industrialization of the domestic numerical control equipment of our country. In latter stage for "the Ninth Five-Year Plan ", the domestic occupation rate of market of the domestic numerical control lathe is up to 50%, it is up to 10% too to mix the domestic numerical control system (popular).
Make a general survey of the development course in the past 50 years of technology of numerical control of our country, especially through tackling key problems of 4 Five-Year Plans, all in all has made following achievements.
a. Have established the foundation of the technical development of numerical control, has mastered modern numerical control technology basically. Our country has already, the numerical control host computer, basic technology of special plane and fittings grasped and driven from the numerical control system and survey basically now, among them most technology have already possessed and commercialized the foundation developed, some technology has already, industrialization commercialized.#p#分頁標(biāo)題#e#
b. Have formed the industrial base of numerical control tentatively. In tackling key problems the foundation that the achievement and some technology commercialize, set up the systematic factories of numerical control with production capacity in batches such as numerical control in Central China, numerical control of the spaceflight etc.. Electrical machinery plant of Lanzhou, such factory and the first machine tool plant of Beijing , the first machine tool plant of Jinan ,etc. several numerical control host computer factories of a batch of servo systems and servo electrical machineries as the numerical control in Central China, etc.. These factories have formed the numerical control industrial base of our country basically.
c. Have set up a numerical control research, development, managerial talent's basic team.
Though has made considerable progress in research and development and industrialization of numerical control technology, but we will realize soberly, the research and development of the technology of advanced numerical control of our country, especially there is greater disparity in current situation and current demand of our country of engineering level in industrialization. Though very fast from watching the development of our country vertically, have disparity horizontally more than (compare foreign countries with) not merely engineering level, there is disparity too in development speed in some aspects, namely the engineering level disparity between some high-grade , precision and advanced numerical control equipment has the tendency to expand . Watch from world, estimate roughly as follows about the engineering level of numerical control of our country and industrialization level.
a. On the engineering level, in probably backward 10-1 years with the advanced level in foreign countries, it is bigger in high-quality precision and sophisticated technology.
b. On the industrialization level, the occupation rate of market is low, the variety coverage rate is little, have not formed the large-scale production yet; The specialized level of production of function part and ability of forming a complete set are relatively low; Appearance quality is relatively poor; Dependability is not high, the commercialized degree is insufficient; One's own brand effect that the domestic numerical control system has not been set up yet, users have insufficient confidence.
c. On the ability of sustainable development, research and development of numerical control technology, project ability is relatively weak to the competition; It is not strong that the technological application of numerical control expands dynamics; Research, formulation that relevant standards are normal lag behind.
It is analyzed that the main reason for having above-mentioned disparity has the following several respect.
a. Realize the respect. Know to industry's process arduousness , complexity and long-term characteristic of domestic numerical control insufficiently; It is difficult to underestimate to add strangling, system, etc. to the unstandard, foreign blockade of the market; It is not enough to analyse to the technological application level and ability of numerical control of our country. #p#分頁標(biāo)題#e#
b. System. Pay close attention to numerical control industrialization many in the issue, consider numerical control industrialization little in the issue synthetically in terms of the systematic one, industry chain in terms of technology; Have not set up related system, perfect training , service network of intact high quality ,etc. and supported the system.
c. Mechanism. It causes the brain drain, restraining technology and technological route from innovating again, products innovation that the bad machine is made, and has restricted the effective implementation of planning, has often planned the ideal, implement the difficulty.
d. Technology. The autonomous innovation in technology of enterprises is indifferent; the project of key technology is indifferent. The standard of the lathe lags behind, the level is relatively low, it is not enough for new standard of the numerical control system to study.
7 pairs of strategic thinking of technology and industrialized development of numerical control of our country
7.1 Strategic consideration
Our country make big country, industry is it is it accept front instead of transformation of back end to try one's best to want in shifting in world, namely should master and make key technology advanced, otherwise in a new round of international industrial structure adjustment, the manufacturing industry of our country will step forward and " leave the core spaces ". We regard resource, environment , market as the cost, it is only an international " machining center " in the new economic pattern of the world to exchange the possibility got and " assemble the centre ", but not master the position of the manufacturing center of key technology , will so influence the development process of the modern manufacturing industry of our country seriously.
We should stand in the height of national security strategy paying attention to numerical control technology and industry's question , at first seen from social safety, because manufacturing industry whether our country obtain employment most populous trade, the development of manufacturing industry not only can improve the people's living standard but also can alleviate the pressure of employment of our country , ensure the stability of the society; Secondly seen from national defense security, the western developed country has classified all the high-grade , precision and advanced numerical control products as the strategic materials of the country, realizing the embargo and restriction to our country, " Toshiba incident " and " Cox Report " is the best illustration.
7.2 Development tactics
Proceed from the angles of the fundamental realities of the country of our country, regard the strategic demand of the country and market demand of national economy as the direction, regard improving our country and making the comprehensive competitive power of equipping industry and industrialization level as the goal, use the systematic method , be able to choose to make key technology upgraded in development of equipping industry and support technology supporting the development of industrialization in our country in initial stage of 21st century in leading factor, the ability to supply the necessary technology realizes making the jump development of the equipping industry as the content of research and development . #p#分頁標(biāo)題#e#
Emphasize market demand is a direction, namely take terminal products of numerical control as the core, with the complete machine (Such as the numerical control lathe having a large capacity and a wide range, milling machine, high speed high precise high-performance numerical control lathe, digitized machinery of model, key industry key equipment, etc.) drive the development of the numerical control industry. Solve the numerical control system and relevant functions part especially The dependability that (digitized servo system and electrical machinery, high speed electric main shaft system and new-enclosure that equip, etc.) and production scale question. There are no products that scale will not have high dependability; Will not have cheap and products rich in the competitiveness without scale; Certainly, it is difficult to have day holding up one's head finally that there is no scale Chinese numerical control equipment.
In equiping researching and developing high-grade , precision and advancedly , should emphasize the production, learning and research and close combination of the end user, regard " drawing, using, selling " as the goal, tackle key problems according to the national will, in order to solve the needing badly of the country.
Numerical control technology, emphasized innovation, put emphasis on researching and developing the technology and products with independent intellectual property right before the competition, establish the foundation for the industry of numerical control of our country, sustainable development of equipment manufacture and even the whole manufacturing industry.
英文翻譯對照
高速銑削
高速切削加工是一種先進(jìn)制造技術(shù),不同于傳統(tǒng)加工方式。它的主軸轉(zhuǎn)速高、切削進(jìn)給速度高、切削量小,單位時間內(nèi)的材料切除量卻增加3~6 倍。它以高效率、高精度和高表面質(zhì)量為基本特征,在汽車工業(yè)、航空航天、模具制造和儀器儀表等行業(yè)中獲得了廣泛的應(yīng)用,取得了重大的經(jīng)濟效益,是當(dāng)代先進(jìn)制造技術(shù)的重要應(yīng)用。長期以來,人們對模具的加工一直采用銑削一磨削或者電火花(EDM)加工、打磨、拋光的方法。雖然電火花可加工硬度很高的工件,但較低的生產(chǎn)率使它的應(yīng)用受到制。隨著高速加工技術(shù)的發(fā)展,采用高速切削取代磨削拋光和電加工進(jìn)行模具加工已成為可能。使加工周期大為縮短,加工質(zhì)量得到可靠保證,加工成本降低。
1 高速切削加工的優(yōu)勢
高速切削加工作為模具制造中集高效、優(yōu)質(zhì)、低耗于一身的先進(jìn)制造技術(shù)。在常規(guī)切削加工中備受困擾的一系列問題,通過高速切削加工的應(yīng)用得到了解決。
1.1 提高生產(chǎn)率
高速切削的主軸轉(zhuǎn)速、進(jìn)給速度與傳統(tǒng)切削加工相比,發(fā)生了本質(zhì)性的飛躍,其金屬切除率提高了30%~40%,切削力降低了30%,刀具的切削壽命提高了70%。還可加工淬硬零件,許多零件一次裝夾可完成粗、半精和精加工等全部工序,對復(fù)雜型面也能達(dá)到零件表面質(zhì)量要求,進(jìn)而提高了加工生產(chǎn)率和產(chǎn)品的市場競爭力。#p#分頁標(biāo)題#e#
1.2 改善加工精度和表面質(zhì)量
高速機床普遍具備高剛性和高精度等特點,加工時切削深度小,而進(jìn)給速度較快,切削力低,工件熱變形減少,而加工精度很高,表面粗糙度很小。高速銑削可獲得無銑痕的加工表面,使零件表面質(zhì)量大大提高。加工鋁合金時可達(dá)Ra0.40.6um,加工鋼件時可達(dá)Ra0.2~0.4um。
1.3 減少切削產(chǎn)生的熱量
因為銑床主軸高速旋轉(zhuǎn),切削加工是淺切削,同時進(jìn)給速度很快,刀刃和工件的接觸長度和接觸時間非常短,減少了刀刃和工件的熱傳導(dǎo)。高速切削采用干銑或油一氣(油霧)潤滑系統(tǒng),避免了傳統(tǒng)加工時在刀具和工件接觸處產(chǎn)生大量熱的缺點,保證刀具在溫度不高的條件下工作,延長了刀具的使用壽命。
1.4 有利于加工薄壁零件
高速切削時的切削力小,有較高的穩(wěn)定性,可加工高質(zhì)量同本公司內(nèi)部員工相比可能是非常優(yōu)秀的,但是同其他的公司的員工相比工作績效可能算不了優(yōu)秀。就我們中國實際來說,我們使用標(biāo)桿分析法來確定員工培訓(xùn)需求是簡單有效的。這種學(xué)習(xí)標(biāo)桿對象可以是外部的,也可以是內(nèi)部和外部的結(jié)合。首先要明確企業(yè)的發(fā)展戰(zhàn)略。通過對企業(yè)內(nèi)外部環(huán)境和組織資源等分析,明確企業(yè)未來發(fā)展的目標(biāo)和業(yè)務(wù)重點。根據(jù)企業(yè)的發(fā)展戰(zhàn)略尋找可以比照的標(biāo)桿企業(yè),通過比較分析,最后確定標(biāo)桿企業(yè)。在確定標(biāo)桿企業(yè)后,有一項,是了解其發(fā)展戰(zhàn)略,還是其市場占有率和市場增長率,還是員工各方面的情況等等,這要根據(jù)本企業(yè)的實際情況來確定。由于企業(yè)在不同的發(fā)展時期,其著力點是不同的,即企業(yè)需要投入的物力人力財力的重點是不同的。所以在一定的時期內(nèi),企業(yè)要準(zhǔn)確地選定其跟標(biāo)桿企業(yè)比較的部門和崗位,這樣更加具有實際意義,因為標(biāo)桿企業(yè)并不是處處都好,而且有些方面進(jìn)行比較沒有多少實際意義,再者這樣可以更充分地集中利用企業(yè)的有限資源。確定標(biāo)桿企業(yè)后,然后拿本企業(yè)的相應(yīng)的部門和員工同標(biāo)桿企業(yè)進(jìn)行比較,可以發(fā)現(xiàn)兩者在工作績效的差距,比較分析,尋找原因,根據(jù)本企業(yè)的實際,最后確定培訓(xùn)需求。培訓(xùn)是需要成本的,如果沒有通過有效的方式,去確定企業(yè)是否需要培訓(xùn)以及培訓(xùn)的方式,而是盲目進(jìn)行培訓(xùn),這樣的培訓(xùn)是難以取得預(yù)期的效果。有比較才有區(qū)別,這種培訓(xùn)分析模型簡單實用。
1.5 可部分替代某些工藝,如電火花加工、磨削加工
高速切削的一大特點,高速切削已可加工硬度達(dá)代寫essay HRC60 的零件。采用帶涂層的硬質(zhì)合金刀具加工模具,直接將淬硬工具鋼一次安裝加工成形,有效地避免了零件多次安裝造成的裝夾誤差,提高了零件的幾何位置精度。在傳統(tǒng)加工模具的工藝中,對熱處理硬化后的工件需進(jìn)行電火花加工,用高速切削加工替代傳統(tǒng)切削的加工方法,可以省去模具制造工藝中的電火花加工,簡化了加工工藝和投資成本。#p#分頁標(biāo)題#e#
高速銑削加工可在專用的CNC 機床或加工中心上進(jìn)行,也可在加裝高速主軸的普通機床上進(jìn)行。后者不僅具有普通機床的加工能力,而且還可進(jìn)行高速銑削,減少了設(shè)備投資,增加了機床柔性。高速切削可以使加工效率提高、質(zhì)量提高、工序簡化,機床投資和刀具投資及維護費用上升,但綜合比較,可以顯著提高經(jīng)濟效益。
2 高速銑削加工
高速銑削加工的主要技術(shù)高速切削技術(shù)是切削加工技術(shù)的發(fā)展方向之一,它隨著C N C 技術(shù)、微電子技術(shù)、新材料和新工藝等技術(shù)的發(fā)展而邁上更高的臺階。高速機床和高速刀具是實現(xiàn)高速切削的前提和基本條件,在高速切削加工中對高速機床的性能和刀具材料的選擇有嚴(yán)格的要求。
2.1 高速銑削加工機床為了實現(xiàn)高速切削加工
一般采用高柔性的高速數(shù)控機床、加工中心,也有的采用專用的高速銑、鉆床。機床同時具有高速主軸系統(tǒng)和高速進(jìn)給系統(tǒng),高的主軸剛度特性,高精度定位功能和高精度插補功能,特別是圓弧高精度插補功能。高速切削加工對機床的工藝系統(tǒng)提出了更高的要求,主要表現(xiàn)在以下幾個方面:
高速銑削機床必須具有高速主軸,主軸的轉(zhuǎn)速10000~100000m/min,功率大于15kW。還應(yīng)具有快速升速、在指定位置快速準(zhǔn)停的性能。主軸的軸向間隙不大于0 .0 0 0 2 m m 。高速主軸常采用液體靜壓軸承式、空氣靜壓軸承式、混合陶瓷軸承、磁懸浮軸承式等結(jié)構(gòu)形式。主軸冷卻一般采用內(nèi)部水冷或氣冷。
高速加工機床的驅(qū)動系統(tǒng)應(yīng)能夠提供40~60m/min 的進(jìn)給速度,具有良好的加速度特性,能夠提供0.4m/s2 到10m/s2的加速度和減速度。為了獲得良好的加工質(zhì)量,高速切削機床必須具有足夠高的剛度。機床床身材料采用灰鑄鐵,還可以在底座中添加高阻尼特性的混凝土,以防止切削時刀具顫振影響加工質(zhì)量。具有高速數(shù)據(jù)傳輸率,能夠自動加減速。加工工藝有利于切削加工和提高刀具壽命。目前高速機床的廠家,通常在普通機床上進(jìn)行低速、大進(jìn)給的粗加工,然后進(jìn)行熱處理,最后在高速機床上進(jìn)行半精加工和精加工,在提高精度和效率的同時盡可能地降低加工成本。
2.2 高速切削加工刀具
刀具是高速切削加工中最活躍重要的因素之一,它直接影響著加工效率、制造成本和產(chǎn)品的加工精度。刀具在高速加工過程中要承受高溫、高壓、摩擦、沖擊和振動等載荷,因此其硬度和耐磨性、強度和韌性、耐熱性、工藝性能和經(jīng)濟性等基本性能是實現(xiàn)高速加工的關(guān)鍵因素之一。高速切削加工的刀具技術(shù)發(fā)展速度很快,應(yīng)用較多的如金剛石(P C D)、立方氮化硼(C B N))、陶瓷刀具、涂層硬質(zhì)合金、(碳)氮化鈦硬質(zhì)合金T I C (N)等。立方氮化硼具有很高的硬度、極強的耐磨性和良好的導(dǎo)熱性,與鐵族元素之間有很大的惰性,在1300℃也不會發(fā)生顯著的化學(xué)作用,還具有良好的穩(wěn)定性。實驗表明,用CBN 刀具切削硬度HRC35~67 的淬火鋼可以達(dá)到很高速度。陶瓷材料具有良好的耐磨性和熱化學(xué)穩(wěn)定性,其硬度、韌性低于C B N ,可用于加工硬度H R C < 5 0 的零件。硬質(zhì)合金刀具耐磨性好,但硬度比立方氮化硼和陶瓷低。采用刀具涂層技術(shù),可以提高刀具硬度和切削加工的速度,適合切削硬度在HRC40~50 之間的工件??捎糜谀蜔岷辖?、鈦合金、高溫合金、鑄鐵、純鋼、鋁合金及復(fù)合材料的高速切削,應(yīng)用最為廣泛。精密加工有色金屬或非金屬材料時,選用聚晶金剛石或金剛石涂層刀具。#p#分頁標(biāo)題#e#
2.3 高速加工工藝
高速切削的工藝技術(shù)也是進(jìn)行高速切削加工的關(guān)鍵。切削方法選擇不當(dāng),會使刀具加劇磨損,達(dá)不到高速加工的目的。只有高速機床和刀具沒有好的工藝技術(shù)指導(dǎo),高速切削加工設(shè)備也不能充分發(fā)揮作用。在高速切削加工中,應(yīng)盡量選用順銑加工,順銑時刀具切入工件的切屑厚度為最大,隨后逐漸減小。高速切削加工適于淺的切深,切削深度不超過0.2mm,可避免刀具的位置偏差,確保加工零件的幾何精度。保證工件上的切削載荷恒定,以獲得好的加工質(zhì)量。高速切削采用單一路徑順銑切削模式,盡量不中斷切削過程和刀具路徑,減少刀具的切入切出次數(shù),以獲得相對穩(wěn)定的切削過程。減少刀具的急速換向,在換向時NC機床必須立即停止或降速,再執(zhí)行下一步操作。由于機床的加速度限制,易造成時間浪費,而且急?;蚣眲訒茐谋砻婢?。在模具的高速精加工中,在每次切入、切出工件時,進(jìn)給方向的改變應(yīng)盡量采用圓弧或曲線轉(zhuǎn)接,避免采用直線轉(zhuǎn)接,以保持切削過程的平穩(wěn)性。
3 高速銑削在模具加工中的應(yīng)用
高速銑削作為高效切削加工的新方法,在模具制造中得到了廣泛應(yīng)用。在常規(guī)生產(chǎn)連桿鍛模時,用電火花加工型腔需12~15h,電極制作2h。改用高速銑削后,采用高速立銑刀對硬度H R C 6 0 的淬硬工具鋼進(jìn)行加工。整個鍛模加工只需3h20min,工效提高4~5 倍,加工表面粗糙度達(dá)Ra0.5~0.6m ,質(zhì)量完全符合要求。
高速切削技術(shù)是切削加工技術(shù)的主要發(fā)展方向之一,目前主要應(yīng)用于汽車工業(yè)和模具行業(yè),尤其是在加工復(fù)雜曲面、工件本身或刀具剛性要求較高的加工領(lǐng)域等,是多種先進(jìn)加工技術(shù)的集成,其高效、高質(zhì)量為人們所推崇。它不僅涉及到高速加工工藝,而且還包括高速加工機床、數(shù)控系統(tǒng)、高速切削刀具及C A D / C A M 技術(shù)等。模具高速加工技術(shù)目前已在發(fā)達(dá)國家的模具制造業(yè)中普遍應(yīng)用,而在我國的應(yīng)用范圍及應(yīng)用水平仍有待提高,由于其具有傳統(tǒng)加工無可比擬的優(yōu)勢,仍將是今后加工技術(shù)必然的發(fā)展方向。
4 數(shù)控技術(shù)和裝備發(fā)展趨勢及對策
裝備工業(yè)的技術(shù)水平和現(xiàn)代化程度決定著整個國民經(jīng)濟的水平和現(xiàn)代化程度,數(shù)控技術(shù)及裝備是發(fā)展新興高新技術(shù)產(chǎn)業(yè)和尖端工業(yè)(如信息技術(shù)及其產(chǎn)業(yè)、生物技術(shù)及其產(chǎn)業(yè)、航空、航天等國防工業(yè)產(chǎn)業(yè))的使能技術(shù)和最基本的裝備。馬克思曾經(jīng)說過“各種經(jīng)濟時代的區(qū)別,不在于生產(chǎn)什么,而在于怎樣生產(chǎn),用什么勞動資料生產(chǎn)”。制造技術(shù)和裝備就是人類生產(chǎn)活動的最基本的生產(chǎn)資料,而數(shù)控技術(shù)又是當(dāng)今先進(jìn)制造技術(shù)和裝備最為核心的技術(shù)。當(dāng)今世界各國制造業(yè)廣泛采用數(shù)控技術(shù),以提高制造能力和水平,提高對動態(tài)多變市場的適應(yīng)能力和競爭能力。此外,世界上各工業(yè)發(fā)達(dá)國家還將數(shù)控技術(shù)及數(shù)控裝備列為#p#分頁標(biāo)題#e#代寫英語dissertation國家的戰(zhàn)略物資,不僅采取重大措施來發(fā)展自己的數(shù)控技術(shù)及其產(chǎn)業(yè),而且在“高精尖”數(shù)控關(guān)鍵技術(shù)和裝備方面對我國實行封鎖和限制政策??傊罅Πl(fā)展以數(shù)控技術(shù)為核心的先進(jìn)制造技術(shù)已成為世界各發(fā)達(dá)國家加速經(jīng)濟發(fā)展、提高綜合國力和國家地位的重要途徑。
數(shù)控技術(shù)是用數(shù)字信息對機械運動和工作過程進(jìn)行控制的技術(shù),數(shù)控裝備是以數(shù)控技術(shù)為代表的新技術(shù)對傳統(tǒng)制造產(chǎn)業(yè)和新興制造業(yè)的滲透形成的機電一體化產(chǎn)品,即所謂的數(shù)字化裝備,其技術(shù)范圍覆蓋很多領(lǐng)域:(1)機械制造技術(shù);(2)信息處理、加工、傳輸技術(shù);(3)自動控制技術(shù);(4)伺服驅(qū)動技術(shù);(5)傳感器技術(shù);(6)軟件技術(shù)等。
5 數(shù)控技術(shù)的發(fā)展趨勢
數(shù)控技術(shù)的應(yīng)用不但給傳統(tǒng)制造業(yè)帶來了革命性的變化,使制造業(yè)成為工業(yè)化的象征,而且隨著數(shù)控技術(shù)的不斷發(fā)展和應(yīng)用領(lǐng)域的擴大,他對國計民生的一些重要行業(yè)(IT、汽車、輕工、醫(yī)療等)的發(fā)展起著越來越重要的作用,因為這些行業(yè)所需裝備的數(shù)字化已是現(xiàn)代發(fā)展的大趨勢。從目前世界上數(shù)控技術(shù)及其裝備發(fā)展的趨勢來看,其主要研究熱點有以下幾個方面[1~4]。
5.1 高速、高精加工技術(shù)及裝備的新趨勢
效率、質(zhì)量是先進(jìn)制造技術(shù)的主體。高速、高精加工技術(shù)可極大地提高效率,提高產(chǎn)品的質(zhì)量和檔次,縮短生產(chǎn)周期和提高市場競爭能力。為此日本先端技術(shù)研究會將其列為5大現(xiàn)代制造技術(shù)之一,國際生產(chǎn)工程學(xué)會(CIRP)將其確定為21世紀(jì)的中心研究方向之一。
在轎車工業(yè)領(lǐng)域,年產(chǎn)30萬輛的生產(chǎn)節(jié)拍是40秒/輛,而且多品種加工是轎車裝備必須解決的重點問題之一;在航空和宇航工業(yè)領(lǐng)域,其加工的零部件多為薄壁和薄筋,剛度很差,材料為鋁或鋁合金,只有在高切削速度和切削力很小的情況下,才能對這些筋、壁進(jìn)行加工。近來采用大型整體鋁合金坯料“掏空”的方法來制造機翼、機身等大型零件來替代多個零件通過眾多的鉚釘、螺釘和其他聯(lián)結(jié)方式拼裝,使構(gòu)件的強度、剛度和可靠性得到提高。這些都對加工裝備提出了高速、高精和高柔性的要求。
從EMO2001展會情況來看,高速加工中心進(jìn)給速度可達(dá)80m/min,甚至更高,空運行速度可達(dá)100m/min左右。目前世界上許多汽車廠,包括我國的上海通用汽車公司,已經(jīng)采用以高速加工中心組成的生產(chǎn)線部分替代組合機床。美國CINCINNATI公司的HyperMach機床進(jìn)給速度最大達(dá)60m/min,快速為100m/min,加速度達(dá)2g,主軸轉(zhuǎn)速已達(dá)60 000r/min。加工一個薄壁飛機零件,只用30min,而同樣的零件在一般高速銑床加工需3h,在普通銑床加工需8h;德國DMG公司的雙主軸車床的主軸速度及加速度分別達(dá)120000r/mm和1g。#p#分頁標(biāo)題#e#
在加工精度方面,近10年來,普通級數(shù)控機床的加工精度已由10μm提高到5μm,精密級加工中心則從3~5μm,提高到1~1.5μm,并且超精密加工精度已開始進(jìn)入納米級(0.01μm)。
在可靠性方面,國外數(shù)控裝置的MTBF值已達(dá)6 000h以上,伺服系統(tǒng)的MTBF值達(dá)到30000h以上,表現(xiàn)出非常高的可靠性。
為了實現(xiàn)高速、高精加工,與之配套的功能部件如電主軸、直線電機得到了快速的發(fā)展,應(yīng)用領(lǐng)域進(jìn)一步擴大。
5.2 五軸聯(lián)動加工和復(fù)合加工機床快速發(fā)展
采用5軸聯(lián)動對三維曲面零件的加工,可用刀具最佳幾何形狀進(jìn)行切削,不僅光潔度高,而且效率也大幅度提高。一般認(rèn)為,1臺5軸聯(lián)動機床的效率可以等于2臺3軸聯(lián)動機床,特別是使用立方氮化硼等超硬材料銑刀進(jìn)行高速銑削淬硬鋼零件時,5軸聯(lián)動加工可比3軸聯(lián)動加工發(fā)揮更高的效益。但過去因5軸聯(lián)動數(shù)控系統(tǒng)、主機結(jié)構(gòu)復(fù)雜等原因,其價格要比3軸聯(lián)動數(shù)控機床高出數(shù)倍,加之編程技術(shù)難度較大,制約了5軸聯(lián)動機床的發(fā)展。
當(dāng)前由于電主軸的出現(xiàn),使得實現(xiàn)5軸聯(lián)動加工的復(fù)合主軸頭結(jié)構(gòu)大為簡化,其制造難度和成本大幅度降低,數(shù)控系統(tǒng)的價格差距縮小。因此促進(jìn)了復(fù)合主軸頭類型5軸聯(lián)動機床和復(fù)合加工機床(含5面加工機床)的發(fā)展。
在EMO2001展會上,新日本工機的5面加工機床采用復(fù)合主軸頭,可實現(xiàn)4個垂直平面的加工和任意角度的加工,使得5面加工和5軸加工可在同一臺機床上實現(xiàn),還可實現(xiàn)傾斜面和倒錐孔的加工。德國DMG公司展出DMUVoution系列加工中心,可在一次裝夾下實現(xiàn)5面加工和5軸聯(lián)動加工,可由CNC系統(tǒng)控制或CAD/CAM直接或間接控制。
5.3 智能化、開放式、網(wǎng)絡(luò)化成為當(dāng)代數(shù)控系統(tǒng)發(fā)展的主要趨勢
21世紀(jì)的數(shù)控裝備將是具有一定智能化的系統(tǒng),智能化的內(nèi)容包括在數(shù)控系統(tǒng)中的各個方面:為追求加工效率和加工質(zhì)量方面的智能化,如加工過程的自適應(yīng)控制,工藝參數(shù)自動生成;為提高驅(qū)動性能及使用連接方便的智能化,如前饋控制、電機參數(shù)的自適應(yīng)運算、自動識別負(fù)載自動選定模型、自整定等;簡化編程、簡化操作方面的智能化,如智能化的自動編程、智能化的人機界面等;還有智能診斷、智能監(jiān)控方面的內(nèi)容、方便系統(tǒng)的診斷及維修等。
為解決傳統(tǒng)的數(shù)控系統(tǒng)封閉性和數(shù)控應(yīng)用軟件的產(chǎn)業(yè)化生產(chǎn)存在的問題。目前許多國家對開放式數(shù)控系統(tǒng)進(jìn)行研究,如美國的NGC(The Next Generation Work-Station/Machine Control)、歐共體的OSACA(Open System Architecture for Control within Automation Systems)、日本的OSEC(Open System Environment for Controller),中國的ONC(Open Numerical Control System)等。數(shù)控系統(tǒng)開放化已經(jīng)成為數(shù)控系統(tǒng)的未來之路。所謂開放式數(shù)控系統(tǒng)就是數(shù)控系統(tǒng)的開發(fā)可以在統(tǒng)一的運行平臺上,面向機床廠家和最終用戶,通過改變、增加或剪裁結(jié)構(gòu)對象(數(shù)控功能),形成系列化,并可方便地將用戶的特殊應(yīng)用和技術(shù)訣竅集成到控制系統(tǒng)中,快速實現(xiàn)不同品種、不同檔次的開放式數(shù)控系統(tǒng),形成具有鮮明個性的名牌產(chǎn)品。目前開放式數(shù)控系統(tǒng)的體系結(jié)構(gòu)規(guī)范、通信規(guī)范、配置規(guī)范、運行平臺、數(shù)控系統(tǒng)功能庫以及數(shù)控系統(tǒng)功能軟件開發(fā)工具等是當(dāng)前研究的核心。#p#分頁標(biāo)題#e#
網(wǎng)絡(luò)化數(shù)控裝備是近兩年國際著名機床博覽會的一個新亮點。數(shù)控裝備的網(wǎng)絡(luò)化將極大地滿足生產(chǎn)線、制造系統(tǒng)、制造企業(yè)對信息集成的需求,也是實現(xiàn)新的制造模式如敏捷制造、虛擬企業(yè)、全球制造的基礎(chǔ)單元。國內(nèi)外一些著名數(shù)控機床和數(shù)控系統(tǒng)制造公司都在近兩年推出了相關(guān)的新概念和樣機,如在EMO2001展中,日本山崎馬扎克(Mazak)公司展出的“CyberProduction Center”(智能生產(chǎn)控制中心,簡稱CPC);日本大隈(Okuma)機床公司展出“IT plaza”(信息技術(shù)廣場,簡稱IT廣場);德國西門子(Siemens)公司展出的Open Manufacturing Environment(開放制造環(huán)境,簡稱OME)等,反映了數(shù)控機床加工向網(wǎng)絡(luò)化方向發(fā)展的趨勢。
5.4 重視新技術(shù)標(biāo)準(zhǔn)、規(guī)范的建立
5.4.1 關(guān)于數(shù)控系統(tǒng)設(shè)計開發(fā)規(guī)范
如前所述,開放式數(shù)控系統(tǒng)有更好的通用性、柔性、適應(yīng)性、擴展性,美國、歐共體和日本等國紛紛實施戰(zhàn)略發(fā)展計劃,并進(jìn)行開放式體系結(jié)構(gòu)數(shù)控系統(tǒng)規(guī)范(OMAC、OSACA、OSEC)的研究和制定,世界3個最大的經(jīng)濟體在短期內(nèi)進(jìn)行了幾乎相同的科學(xué)計劃和規(guī)范的制定,預(yù)示了數(shù)控技術(shù)的一個新的變革時期的來臨。我國在2000年也開始進(jìn)行中國的ONC數(shù)控系統(tǒng)的規(guī)范框架的研究和制定。
5.4.2 關(guān)于數(shù)控標(biāo)準(zhǔn)
數(shù)控標(biāo)準(zhǔn)是制造業(yè)信息化發(fā)展的一種趨勢。數(shù)控技術(shù)誕生后的50年間的信息交換都是基于ISO6983標(biāo)準(zhǔn),即采用G,M代碼描述如何(how)加工,其本質(zhì)特征是面向加工過程,顯然,他已越來越不能滿足現(xiàn)代數(shù)控技術(shù)高速發(fā)展的需要。為此,國際上正在研究和制定一種新的CNC系統(tǒng)標(biāo)準(zhǔn)ISO14649(STEP-NC),其目的是提供一種不依賴于具體系統(tǒng)的中性機制,能夠描述產(chǎn)品整個生命周期內(nèi)的統(tǒng)一數(shù)據(jù)模型,從而實現(xiàn)整個制造過程,乃至各個工業(yè)領(lǐng)域產(chǎn)品信息的標(biāo)準(zhǔn)化。
STEP-NC的出現(xiàn)可能是數(shù)控技術(shù)領(lǐng)域的一次革命,對于數(shù)控技術(shù)的發(fā)展乃至整個制造業(yè),將產(chǎn)生深遠(yuǎn)的影響。首先,STEP-NC提出一種嶄新的制造理念,傳統(tǒng)的制造理念中,NC加工程序都集中在單個計算機上。而在新標(biāo)準(zhǔn)下,NC程序可以分散在互聯(lián)網(wǎng)上,這正是數(shù)控技術(shù)開放式、網(wǎng)絡(luò)化發(fā)展的方向。其次,STEP-NC數(shù)控系統(tǒng)還可大大減少加工圖紙(約75%)、加工程序編制時間(約35%)和加工時間(約50%)。
目前,歐美國家非常重視STEP-NC的研究,歐洲發(fā)起了STEP-NC的IMS計劃(1999.1.1~2001.12.31)。參加這項計劃的有來自歐洲和日本的20個CAD/CAM/CAPP/CNC用戶、廠商和學(xué)術(shù)機構(gòu)。美國的STEP Tools公司是全球范圍內(nèi)制造業(yè)數(shù)據(jù)交換軟件的開發(fā)者,他已經(jīng)開發(fā)了用作數(shù)控機床加工信息交換的超級模型(Super Model),其目標(biāo)是用統(tǒng)一的規(guī)范描述所有加工過程。目前這種新的數(shù)據(jù)交換格式已經(jīng)在配備了SIEMENS、FIDIA以及歐洲OSACA-NC數(shù)控系統(tǒng)的原型樣機上進(jìn)行了驗證。#p#分頁標(biāo)題#e#
6 對我國數(shù)控技術(shù)及其產(chǎn)業(yè)發(fā)展的基本估計
我國數(shù)控技術(shù)起步于1958年,近50年的發(fā)展歷程大致可分為3個階段:第一階段從1958年到1979年,即封閉式發(fā)展階段。在此階段,由于國外的技術(shù)封鎖和我國的基礎(chǔ)條件的限制,數(shù)控技術(shù)的發(fā)展較為緩慢。第二階段是在國家的“六五”、“七五”期間以及“八五”的前期,即引進(jìn)技術(shù),消化吸收,初步建立起國產(chǎn)化體系階段。在此階段,由于改革開放和國家的重視,以及研究開發(fā)環(huán)境和國際環(huán)境的改善,我國數(shù)控技術(shù)的研究、開發(fā)以及在產(chǎn)品的國產(chǎn)化方面都取得了長足的進(jìn)步。第三階段是在國家的“八五”的后期和“九五”期間,即實施產(chǎn)業(yè)化的研究,進(jìn)入市場競爭階段。在此階段,我國國產(chǎn)數(shù)控裝備的產(chǎn)業(yè)化取得了實質(zhì)性進(jìn)步。在“九五”末期,國產(chǎn)數(shù)控機床的國內(nèi)市場占有率達(dá)50%,配國產(chǎn)數(shù)控系統(tǒng)(普及型)也達(dá)到了10%。
縱觀我國數(shù)控技術(shù)近50年的發(fā)展歷程,特別是經(jīng)過4個5年計劃的攻關(guān),總體來看取得了以下成績。
a. 奠定了數(shù)控技術(shù)發(fā)展的基礎(chǔ),基本掌握了現(xiàn)代數(shù)控技術(shù)。我國現(xiàn)在已基本掌握了從數(shù)控系統(tǒng)、伺服驅(qū)動、數(shù)控主機、專機及其配套件的基礎(chǔ)技術(shù),其中大部分技術(shù)已具備進(jìn)行商品化開發(fā)的基礎(chǔ),部分技術(shù)已商品化、產(chǎn)業(yè)化。
b. 初步形成了數(shù)控產(chǎn)業(yè)基地。在攻關(guān)成果和部分技術(shù)商品化的基礎(chǔ)上,建立了諸如華中數(shù)控、航天數(shù)控等具有批量生產(chǎn)能力的數(shù)控系統(tǒng)生產(chǎn)廠。蘭州電機廠、華中數(shù)控等一批伺服系統(tǒng)和伺服電機生產(chǎn)廠以及北京第一機床廠、濟南第一機床廠等若干數(shù)控主機生產(chǎn)廠。這些生產(chǎn)廠基本形成了我國的數(shù)控產(chǎn)業(yè)基地。
c. 建立了一支數(shù)控研究、開發(fā)、管理人才的基本隊伍。
雖然在數(shù)控技術(shù)的研究開發(fā)以及產(chǎn)業(yè)化方面取得了長足的進(jìn)步,但我們也要清醒地認(rèn)識到,我國高端數(shù)控技術(shù)的研究開發(fā),尤其是在產(chǎn)業(yè)化方面的技術(shù)水平現(xiàn)狀與我國的現(xiàn)實需求還有較大的差距。雖然從縱向看我國的發(fā)展速度很快,但橫向比(與國外對比)不僅技術(shù)水平有差距,在某些方面發(fā)展速度也有差距,即一些高精尖的數(shù)控裝備的技術(shù)水平差距有擴大趨勢。從國際上來看,對我國數(shù)控技術(shù)水平和產(chǎn)業(yè)化水平估計大致如下。
a. 技術(shù)水平上,與國外先進(jìn)水平大約落后10~15年,在高精尖技術(shù)方面則更大。
b. 產(chǎn)業(yè)化水平上,市場占有率低,品種覆蓋率小,還沒有形成規(guī)模生產(chǎn);功能部件專業(yè)化生產(chǎn)水平及成套能力較低;外觀質(zhì)量相對差;可靠性不高,商品化程度不足;國產(chǎn)數(shù)控系統(tǒng)尚未建立自己的品牌效應(yīng),用戶信心不足。
c. 可持續(xù)發(fā)展的能力上,對競爭前數(shù)控技術(shù)的研究開發(fā)、工程化能力較弱;數(shù)控技術(shù)應(yīng)用領(lǐng)域拓展力度不強;相關(guān)標(biāo)準(zhǔn)規(guī)范的研究、制定滯后。#p#分頁標(biāo)題#e#
分析存在上述差距的主要原因有以下幾個方面。
a. 認(rèn)識方面。對國產(chǎn)數(shù)控產(chǎn)業(yè)進(jìn)程艱巨性、復(fù)雜性和長期性的特點認(rèn)識不足;對市場的不規(guī)范、國外的封鎖加扼殺、體制等困難估計不足;對我國數(shù)控技術(shù)應(yīng)用水平及能力分析不夠。
b. 體系方面。從技術(shù)的角度關(guān)注數(shù)控產(chǎn)業(yè)化問題的時候多,從系統(tǒng)的、產(chǎn)業(yè)鏈的角度綜合考慮數(shù)控產(chǎn)業(yè)化問題的時候少;沒有建立完整的高質(zhì)量的配套體系、完善的培訓(xùn)、服務(wù)網(wǎng)絡(luò)等支撐體系。
c. 機制方面。不良機制造成人才流失,又制約了技術(shù)及技術(shù)路線創(chuàng)新、產(chǎn)品創(chuàng)新,且制約了規(guī)劃的有效實施,往往規(guī)劃理想,實施困難。
d. 技術(shù)方面。企業(yè)在技術(shù)方面自主創(chuàng)新能力不強,核心技術(shù)的工程化能力不強。機床標(biāo)準(zhǔn)落后,水平較低,數(shù)控系統(tǒng)新標(biāo)準(zhǔn)研究不夠。
7 對我國數(shù)控技術(shù)和產(chǎn)業(yè)化發(fā)展的戰(zhàn)略思考
7.1 戰(zhàn)略考慮
我國是制造大國,在世界產(chǎn)業(yè)轉(zhuǎn)移中要盡量接受前端而不是后端的轉(zhuǎn)移,即要掌握先進(jìn)制造核心技術(shù),否則在新一輪國際產(chǎn)業(yè)結(jié)構(gòu)調(diào)整中,我國制造業(yè)將進(jìn)一步“空芯”。我們以資源、環(huán)境、市場為代價,交換得到的可能僅僅是世界新經(jīng)濟格局中的國際“加工中心”和“組裝中心”,而非掌握核心技術(shù)的制造中心的地位,這樣將會嚴(yán)重影響我國現(xiàn)代制造業(yè)的發(fā)展進(jìn)程。
我們應(yīng)站在國家安全戰(zhàn)略的高度來重視數(shù)控技術(shù)和產(chǎn)業(yè)問題,首先從社會安全看,因為制造業(yè)是我國就業(yè)人口最多的行業(yè),制造業(yè)發(fā)展不僅可提高人民的生活水平,而且還可緩解我國就業(yè)的壓力,保障社會的穩(wěn)定;其次從國防安全看,西方發(fā)達(dá)國家把高精尖數(shù)控產(chǎn)品都列為國家的戰(zhàn)略物質(zhì),對我國實現(xiàn)禁運和限制,“東芝事件”和“考克斯報告”就是最好的例證。
7.2 發(fā)展策略
從我國基本國情的角度出發(fā),以國家的戰(zhàn)略需求和國民經(jīng)濟的市場需求為導(dǎo)向,以提高我國制造裝備業(yè)綜合競爭能力和產(chǎn)業(yè)化水平為目標(biāo),用系統(tǒng)的方法,選擇能夠主導(dǎo)21世紀(jì)初期我國制造裝備業(yè)發(fā)展升級的關(guān)鍵技術(shù)以及支持產(chǎn)業(yè)化發(fā)展的支撐技術(shù)、配套技術(shù)作為研究開發(fā)的內(nèi)容,實現(xiàn)制造裝備業(yè)的跨躍式發(fā)展。
強調(diào)市場需求為導(dǎo)向,即以數(shù)控終端產(chǎn)品為主,以整機(如量大面廣的數(shù)控車床、銑床、高速高精高性能數(shù)控機床、典型數(shù)字化機械、重點行業(yè)關(guān)鍵設(shè)備等)帶動數(shù)控產(chǎn)業(yè)的發(fā)展。重點解決數(shù)控系統(tǒng)和相關(guān)功能部件(數(shù)字化伺服系統(tǒng)與電機、高速電主軸系統(tǒng)和新型裝備的附件等)的可靠性和生產(chǎn)規(guī)模問題。沒有規(guī)模就不會有高可靠性的產(chǎn)品;沒有規(guī)模就不會有價格低廉而富有競爭力的產(chǎn)品;當(dāng)然,沒有規(guī)模中國的數(shù)控裝備最終難以有出頭之日。#p#分頁標(biāo)題#e#
在高精尖裝備研發(fā)方面,要強調(diào)產(chǎn)、學(xué)、研以及最終用戶的緊密結(jié)合,以“做得出、用得上、賣得掉”為目標(biāo),按國家意志實施攻關(guān),以解決國家之急需。
在競爭前數(shù)控技術(shù)方面,強調(diào)創(chuàng)新,強調(diào)研究開發(fā)具有自主知識產(chǎn)權(quán)的技術(shù)和產(chǎn)品,為我國數(shù)控產(chǎn)業(yè)、裝備制造業(yè)乃至整個制造業(yè)的可持續(xù)發(fā)展奠定基礎(chǔ)。
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