外文翻译--模具发展历程 英文版

编号： 毕业设计 (论文 )外文翻译 （ 原 文） 院 （系）： 国防生学院 专 业： 机械设计制造及其自动化 学生姓名： 吕 亮 学 号： 1001120122 指导教师单位： 机电工程学院 姓 名： 杨运泽 职 称： 讲 师 2014 年 3 月 9 日 桂林电子科技大学毕业设计（论文）外文翻译原文 第 1 页 共 28 页 Die history Meorice Wilkes Abstract Functional parts are needed for design verication testing, eld trials, customer evaluation, and production planning. By eliminating multiple steps, the creation of the injec-tion mold directly by a rapid prototyping (RP) process holds the best promise of reducing the time and cost needed to mold low-volume quantities of parts. The potential of this integration of injection molding with RP has been demonstrated many times. What is missing is the fundamental understanding of how the modications to the mold material and RP manufacturing process impact both the mold design and the injection mold ing process. In addition, numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly. In this paper, an integrated approach to accomplish a numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. Comparisons with experimental results are employed for verication, which show that the present scheme is well suited to handle RP fabricated stereolithography (SL) molds. Keywords Injection molding Numerical simulation Rapid prototyping Introduction In injection molding, the polymer melt at high temperature is injected into the mold under high pressure 1. Thus, the mold material needs to have thermal and mechanical properties capable of withstanding the temperatures and pressures of the molding cycle. The focus of many studies has been to create the injection mold directly by a rapid prototyping (RP) process. By eliminating multiple steps, this method of tooling holds the best promise of reducing the time and cost needed to create low-volume quantities of parts in a production material. The potential of integrating injection molding with RP technologies has been demonstrated many times. The properties of RP molds are very different from those of traditional metal molds. The key differences are the properties of thermal conductivity and elastic modulus (rigidity). For example, the polymers used in RP-fabricated stereolithography (SL) molds have a thermal conductivity that is less than one thousandth that of an aluminum tool. In using RP technologies to create molds, the entire mold design and injection-molding process parameters need to be modied and optimized from traditional methodologies due to the completely different tool material. However, there is still not a fundamental understanding of how the modications to the mold tooling method and material impact both the mold design and the injection molding process 桂林电子科技大学毕业设计（论文）外文翻译原文 第 2 页 共 28 页 parameters. One cannot obtain reasonable results by simply changing a few material properties in current models. Also, using traditional approaches when making actual parts may be generating sub-optimal results. So there is a dire need to study the interaction between the rapid tooling (RT) process and material and injection molding, so as to establish the mold design criteria and techniques for an RT-oriented injection molding process. In addition, computer simulation is an effective approach for predicting the quality of molded parts. Commercially available simulation packages of the traditional injection molding process have now become routine tools of the mold designer and process engineer 2. Unfortunately, current simulation programs for conventional injection molding are no longer applicable to RP molds, because of the dramatically dissimilar tool material. For instance, in using the existing simulation software with aluminum and SL molds and comparing with experimental results, though the simulation values of part distortion are reasonable for the aluminum mold, results are unacceptable, with the error exceeding 50%. The distortion during injection molding is due to shrinkage and warpage of the plastic part, as well as the mold. For ordinarily molds, the main factor is the shrinkage and warpage of the plastic part, which is modeled accurately in current simulations. But for RP molds, the distortion of the mold has potentially more inuence, which have been neglected in current models. For instance, 3 used a simple three-step simulation process to consider the mold distortion, which had too much deviation. In this paper, based on the above analysis, a new simulation system for RP molds is developed. The proposed system focuses on predicting part distortion, which is dominating defect in RP-molded parts. The developed simulation can be applied as an evaluation tool for RP mold design and process optimization. Our simulation system is veried by an experimental example. Although many materials are available for use in RP technologies, we concentrate on using stereolithography (SL), the original RP technology, to create polymer molds. The SL process uses photopolymer and laser energy to build a part layer by layer. Using SL takes advantage of both the commercial dominance of SL in the RP industry and the subsequent expertise base that has been developed for creating accurate, high-quality parts. Until recently, SL was primarily used to create physical models for visual inspection and form-t studies with very limited functional applications. However, the newer generation stereolitho graphic photopolymers have improved dimensional, mechanical and thermal properties making it possible to use them for actual functional molds. 桂林电子科技大学毕业设计（论文）外文翻译原文 第 3 页 共 28 页 1 Die position in industrial production Mold is a high-volume products with the shape tool, is the main process of industrial production equipment. With mold components, with high efficiency, good quality, low cost, saving energy and raw materials and a series of advantages, with the mold workpieces possess high accuracy, high complexity, high consistency, high productivity and low consumption , other manufacturing methods can not match. Have already become an important means of industrial production and technological development. The basis of the modern industrial economy. The development of modern industrial and technological level depends largely on the level of industrial development die, so die industry to national economic and social development will play an increasing role. March 1989 the State Council promulgated on the current industrial policy decision points in the mold as the machinery industry transformation sequence of the first, production and capital construction of the second sequence (after the large-scale power generation equipment and the corresponding power transmission equipment), establish tooling industry in an important position in the national economy. Since 1997, they have to mold and its processing technology and equipment included in the current national focus on encouraging the development of industries, products and technologies catalog and to encourage foreign investment industry directory. Approved by the State Council, from 1997 to 2000, more than 80 professional mold factory owned 70% VAT refund of preferential policies to support mold industry. All these have fully demonstrated the development of the State Council and state departments tooling industry attention and support. Mold around the world about the current annual output of 60 billion U.S. dollars, Japan, the United States and other industrialized countries die of industrial output value of more than machine tool industry, beginning in 1997, Chinas industrial output value has exceeded the mold machine tool industry output. According to statistics, home appliances, toys and other light industries, nearly 90% of the parts are integrated with production of chopsticks； in aircraft, automobiles, agricultural machinery and radio industries, the proportion exceeded 60%. Such as aircraft manufacturing, the use of a certain type of fighter dies more than 30,000 units, of which the host 8000 sets, 2000 sets of engines, auxiliary 20 000 sets. From the output of view, since the 80s, the United States, Japan and other industrialized countries die industry output value has exceeded the machine tool industry, and there are still rising. Production technology, according to the International Association predicts that in 2000, the product best pieces of rough 75%, 50% will be finished mold completed； metals, plastics, ceramics, rubber, building 桂林电子科技大学毕业设计（论文）外文翻译原文 第 4 页 共 28 页 materials and other industrial products, most of the mold will be completed in more than 50% metal plates, more than 80% of all plastic products, especially through the mold into. 2 The historical development of mold The emergence of mold can be traced back thousands of years ago, pottery and bronze foundry, but the large-scale use is with the rise of modern industry and developed. The 19th century, with the arms industry (guns shell), watch industry, radio industry, dies are widely used. After World War II, with the rapid development of world economy, it became a mass production of household appliances, automobiles, electronic equipment, cameras, watches and other parts the best way. From a global perspective, when the United States in the forefront of stamping technology - many die of advanced technologies, such as simple mold, high efficiency, mold, die and stamping the high life automation, mostly originated in the United States； and Switzerland, fine blanking, cold in Germany extrusion technology, plastic processing of the Soviet Union are at the world advanced. 50s, mold industry focus is based on subscriber demand, production can meet the product requirements of the mold. Multi-die design rule of thumb, reference has been drawing and perceptual knowledge, on the design of mold parts of a lack of real understanding of function. From 1955 to 1965, is the pressure processing of exploration and develop ment of the times - the main components of the mold and the stress state of the function of a mathematical sub-bridge, and to continue to apply to on-site practical knowledge to make stamping technology in all aspects of a leap in development. The result is summarized mold design principles, and makes the pressure machine, stamping materials, processing methods, plum with a structure, mold materials, mold manufacturing method, the field of automation devices, a new look to the practical direction of advance, so that pressing processing apparatus capable of producing quality products from the first stage. Into the 70s to high speed, launch technology, precision, security, development of the second stage. Continue to emerge in this process a variety of high efficiency, business life, high-precision multi-functional automatic school to help with. Represented by the number of working places as much as other progressive die and dozens of multi-station transfer station module. On this basis, has developed both a continuous pressing station there are more slide forming station of the press - bending machine. In the meantime, the Japanese stand to the worlds largest - the mold into the micron-level precision, die life, alloy tool steel mold has reached tens of millions of times, carbide steel mold to each of hundreds of millions of times p minutes for stamping the number of small presses usually 200 to 300, up to 1200 times to 1500 times. In the meantime, in order to meet product updates quickly, with the short duration (such as cars modified, refurbished toys, etc.) need a variety of economic-type 桂林电子科技大学毕业设计（论文）外文翻译原文 第 5 页 共 28 页 mold, such as zinc alloy die down, polyurethane rubber mold, die steel skin, also has been very great development. From the mid-70s so far can be said that computer-aided design, supporting the continuous development of manufacturing technology of the times. With the precision and complexity of mold rising, accelerating the production cycle, the mold industry, the quality of equipment and personnel are required to improve. Rely on common processing equipment, their experience and skills can not meet the needs of mold. Since the 90s, mechanical and electronic technologies in close connection with the development of NC machine tools, such as CNC wire cutting machine, CNC EDM, CNC milling, CNC coordinate grinding machine and so on. The use of computer automatic programming, control CNC machine tools to improve the efficiency in the use and scope. In recent years, has developed a computer to time-sharing by the way a group of direct management and control of CNC machine tools NNC system. With the development of computer technology, computers have gradually into the mold in all areas, including design, manufacturing and management. International Association for the Study of production forecasts to 2000, as a means of links between design and manufacturing drawings will lose its primary role. Automatic Design of die most fundamental point is to establish the mold standard and design standards. To get rid of the people of the past, and practical experience to judge the composition of the design center, we must take past experiences and ways of thinking, for series, numerical value, the number of type-based, as the design criteria to the computer store. Components are dry because of mold constitutes a million other differences, to come up with a can adapt to various parts of the design software almost impossible. But some products do not change the shape of parts, mold structure has certain rules, can be summed up for the automatic design of software. If a Japanese companys CDM system for progressive die design and manufacturing, including the importation of parts of the figure, rough start, strip layout, determine the size and standard templates, assembly drawing and parts, the output NC program (for CNC machining Center and line cutting program), etc., used in 20% of the time by hand, reduce their working hours to 35 hours； from Japan in the early 80s will be three-dimensional cad / cam system for automotive panel die. Currently, the physical parts scanning input, map lines and data input, geometric form, display, graphics, annotations and the data is automatically programmed, resulting in effective control machine tool control system of post-processing documents have reached a high level； computer Simulation (CAE) technology has made some achievements. At high levels, CAD / CAM / CAE integration, that data is integrated, can transmit 桂林电子科技大学毕业设计（论文）外文翻译原文 第 6 页 共 28 页 information directly with each other. Achieve network. Present. Only a few foreign manufacturers can do it. 3 Chinas mold industry and its development trend Die & Mould Industry Status Due to historical reasons for the formation of closed, big and complete enterprise features, most enterprises in China are equipped with mold workshop, in factory matching status since the late 70s have a mold the concept of industrialization and specialization of production. Production efficiency is not high, poor economic returns. Mold production industry is small and scattered, cross-industry, capital-intensive, professional, commercial and technical management level are relatively low. According to incomplete statistics, there are now specialized in manufacturing mold, the product supporting mold factory workshop (factory) near 17 000, about 600 000 employees, annual output value reached 20 billion yuan mold. However, the existing capacity of the mold and die industry can only meet the demand of 60%, still can not meet the needs of national economic development. At present, the domestic needs of large, sophisticated, complex and long life of the mold also rely mainly on imports. According to customs statistics, in 1997 630 million U.S. dollars worth of imports mold, not including the import of mold together with the equipment； in 1997 only 78 million U.S. dollars export mold. At present the technological level of China Die & Mould Industry and manufacturing capacity, Chinas national economy in the weak links and bottlenecks constraining sustainable economic development. 3.1 Research on the Structure of industrial products mold In accordance with the division of China Mould Industry Association, China mold is divided into 10 basic categories, which, stamping die and plastic molding two categories accounted for the main part. Calculated by output, present, China accounts for about 50% die stamping, plastic molding die about 20%, Wire Drawing Die (Tool) about 10% of the worlds advanced industrial countries and regions, the proportion of plastic forming die die general of the total output value 40%. Most of our stamping die mold for the simple, single-process mode and meet the molds, precision die, precision multi-position progressive die is also one of the few, die less than 100 million times the average life of the mold reached 100 million times the maximum life of more than accuracy 3 5um, more than 50 progressive station, and the international life of 桂林电子科技大学毕业设计（论文）外文翻译原文 第 7 页 共 28 页 the die 600 million times the highest average life of the die 50 million times compared to the mid 80s at the international advanced level. Chinas plastic molding mold design, production technology started relatively late, the overall level of low. Currently a single cavity, a simple mold cavity 70%, and still dominant. A sophisticated multi-cavity mold plastic injection mold, plastic injection mold has been able to multi-color preliminary design and manufacturing. Mould is about 80 million times the average life span is about, the main difference is the large deformation of mold components, excess burr side of a large, poor surface quality, erosion and corrosion serious mold cavity, the mold cavity exhaust poor and vulnerable such as, injection mold 5um accuracy has reached below the highest life expectancy has exceeded 20 million times, the number has more than 100 chamber cavity, reaching the mid 80s to early 90s the international advanced level. 3.2 mold Present Status of Technology Technical level of Chinas mold industry currently uneven, with wide disparities. Generally speaking, with the developed industrial countries, Hong Kong and Taiwan advanced level, there is a large gap. The use of CAD / CAM / CAE / CAPP and other technical design and manufacture molds, both wide application, or technical level, there is a big gap between both. In the application of CAD technology design molds, only about 10% of the mold used in the design of CAD, aside from drawing board still has a long way to go； in the application of CAE design and analysis of mold calculation, it was just started, most of the game is still in trial stages and animation； in the application of CAM technology manufacturing molds, first, the lack of advanced manufacturing equipment, and second, the existing process equipment (including the last 10 years the introduction of advanced equipment) or computer standard (IBM PC and compatibles, HP workstations, etc.) different, or because of differences in bytes, processing speed differences, differences in resistance to electromagnetic interference, networking is low, only about 5% of the mold manufacturing equipment of recent work in this task； in the application process planning CAPP technology, basically a blank state, based on the need for a lot of standardization work； in the mold common technolo gy, such as mold rapid prototyping technology, polishing, electroforming technologies, surface treatment technology aspects of CAD / CAM technology in China has just started. Computer-aided technology, software development, is still at low level, the accumulation of knowledge and experience required. Most of our mold factory, mold processing equipment shop old, long in the length of civilian service, accuracy, low efficiency, still use the ordinary forging, turning, 桂林电子科技大学毕业设计（论文）外文翻译原文 第 8 页 共 28 页 milling, planing, drilling, grinding and processing equipment, mold, heat treatment is still in use salt bath, box-type furnace, operating with the experience of workers, poorly equipped, high energy consumption. Renewal of equipment is slow, technological innovation, technological progress is not much intensity. Although in recent years introduced many advanced mold processing equipment, but are too scattered, or not complete, only about 25% utilization, equipment, some of the advanced functions are not given full play. Lack of technology of high-quality mold design, manufacturing technology and skilled workers, especially the lack of knowledge and breadth, knowledge structure, high levels of compound talents. Chinas mold industry and technical personnel, only 8% of employees 12%, and the technical personnel and skilled workers and lower the overall skill level. Before 1980, practitioners of technical personnel and skilled workers, the aging of knowledge, knowledge structure can not meet the current needs； and staff employed after 80 years, expertise, experience lack of hands-on ability, not ease, do not want to learn technology. In recent years, the brain drain caused by personnel not only decrease the quantity and quality levels, and personnel structure of the emergence of new faults, lean, make mold design, manufacturing difficult to raise the technical level. 3.3 mold industry supporting materials, standard parts of present condition Over the past 10 years, especially the Eighth Five-Year, the State organization of the ministries have repeatedly Material Research Institute, universities and steel enterprises, research and development of special series of die steel, molds and other mold-specific carbide special tools, auxiliary materials, and some promotion. However, due to the quality is not stable enough, the lack of the necessary test conditions and test data, specifications and varieties less, large molds and special mold steel and specifications are required for the gap. In the steel supply, settlement amount and sporadic users of mass-produced steel supply and demand contradiction, yet to be effectively addressed. In addition, in recent years have foreign steel mold set up sales outlets in China, but poor channels, technical services support the weak and prices are high, foreign exchange settlement system and other factors, promote the use of much current. Mold supporting materials and special techniques in recent years despite the popularization and application, but failed to mature production technology, most still also in the exploratory stage tests, such as die coating technology, surface treatment technology mold, mold guide lubrication technology Die sensing technology and lubrication technology, mold to stress technology, mold and other anti-fatigue and anti-corrosion technology productivity has not 桂林电子科技大学毕业设计（论文）外文翻译原文 第 9 页 共 28 页 yet fully formed, towards commercialization. Some key, important technologies also lack the protection of intellectual property. Chinas mold standard parts production, the formation of the early 80s only small-scale production, standardization and standard mold parts using the coverage of about 20%, from the market can be assigned to, is just about 30 varieties, and limited to small and medium size. Standard punch, hot runner components and other supplies just the beginning, mold and parts production and supply channels for poor, poor accuracy and quality. 3.4 Die & Mould Industry Structure in Industrial Organization Chinas mold industry is relatively backward and still could not be called an independent industry. Mold manufacturer in China currently can be divided into four categories: professional mold factory, professional production outside for mold； products factory mold factory or workshop, in order to supply the product works as the main tasks needed to die； die-funded enterprises branch, the organizational model and professional mold factory is similar to small but the main； township mold business, and professional mold factory is similar. Of which the largest number of first-class, mold production accounts for about 70% of total output. Chinas mold industry, decentralized management system. There are 19 major industry sectors manufacture and use of mold, there is no unified management of the department. Only by China Die & Mould Industry Association, overall planning, focus on research, cross-sectoral, inter-departmental management difficulties are many. Mold is suitable for small and medium enterprises organize production, and our technical transformation investment tilted to large and medium enterprises, small and medium enterprise investment mold can not be guaranteed. Including product factory mold shop, factory, including, after the transformation can not quickly recover its investment, or debt-laden, affecting development. Although most products factory mold shop, factory technical force is strong, good equipment conditions, the production of mold levels higher, but equipment utilization rate. Price has long been Chinas mold inconsistent with their value, resulting in mold industry own little economic benefit, social benefit big phenomenon. Dry as dry mold mold standard parts, standard parts dry as dry mold with pieces of production. Dry with parts manufactured products than with the mold of the class of anomalies exist. 桂林电子科技大学毕业设计（论文）外文翻译原文 第 10 页 共 28 页 4 Die trend 4.1 mold CAD / CAE / CAM being integrated, three-dimensional, intelligent and network direction (1) mold software features integrated Die software features of integrated software modules required relatively complete, while the function module using the same data model, in order to achieve Syndicated news management and sharing of information to support the mold design, manufacture, assembly, inspection, testing and production management of the entire process to achieve optimal benefits. Series such as the UK Delcams software will include a surface / solid geometric modeling, engineering drawing complex geometry, advanced rendering industrial design, plastic mold design expert system, complex physical CAM, artistic design and sculpture automatic programming system, reverse engineering and complex systems physical line measurement systems. A higher degree of integration of the software includes: Pro / ENGINEER, UG and CATIA, etc. Shanghai Jiaotong University, China with finite element analysis of metal plastic forming systems and Die CAD / CAM systems； Beijing Beihang Haier Software Ltd. CAXA Series software； Jilin Gold Grid Engineering Research Ce nter of the stamping die mold CAD / CAE / CAM systems . (2) mold design, analysis and manufacture of three-dimensional Two-dimensional mold of traditional structural design can no longer meet modern technical requirements of production and integration. Mold design, analysis, manufacturing three-dimensional technology, paperless software required to mold a new generation of three-dimensional, intuitive sense to design the mold, using three-dimensional digital model can be easily used in the product structure of CAE analysis, tooling manufacturability evaluation and CNC machining, forming process simulation and information management and sharing. Such as Pro / ENGINEER, UG and CATIA software such as with parametric, feature-based, all relevant characteristics, so that mold concurrent engineering po ssible. In addition, Cimatran company Moldexpert, Delcams Ps-mold and Hitachi Shipbuilding of Space-E/mold are professional injection mold 3D design software, interactive 3D cavity, core design, mold base design configuration and typical structure . Australian company Moldflow realistic three-dimensional flow simulation software MoldflowAdvisers been widely praised by users and applications. China Huazhong University of Science have developed similar software HSC3D4.5F and Zhengzhou University, Z-mold software. For manufacturing, knowledge-based intelligent software function is a measure of die important sign of advanced and practical one. Such as injection molding experts Cimatrons software 桂林电子科技大学毕业设计（论文）外文翻译原文 第 11 页 共 28 页 can automatically generate parting direction based parting line and parting surface, generate products corresponding to the core and cavity, implementation of all relevant parts mold, and for automatically generated BOM Form NC drilling process, and can intelligently process parameter setting, calibration and other processing results. (3) mold software applications, networking trend With the mold in the enterprise competition, cooperation, production and management, globalization, internationalization, and the rapid development of computer hardware and software technology, the Internet has made in the mold industry, virtual design, agile manufacturing technology both necessary and possible. The United States in its 21st Century Manufacturing Enterprise Strategy that the auto industry by 2006 to achieve agile manufacturing / virtual engineering solutions to automotive development cycle shortened from 40 months to 4 months. 4.2 mold testing, processing equipment to the precise, efficient, and multi-direction (1) mold testing equipment more sophisticated, efficient Sophisticated, complex, large-scale mold development, testing equipment have become increasingly demanding. Precision Mould precision now reached 2 3m, more domestic manufacturers have to use Italy, the United States, Japan and other countries in the high-precision coordinate measuring machine, and with digital scanning. Such as Dongfeng Motor Mould Factory not only has the capacity 3250mm 3250mm Italian coordinate measuring machine, also has a digital photography optical scanner, the first in the domestic use of digital photography, optical scanning as a means of spatial three-dimensional access to information, enabling the establishment from the measurement of physical model output of engineering drawings the whole process of mold making, reverse engineering a successful technology development and applications. This equipment include: second-generation British Renishaw high-speed scanners (CYCLON SERIES2) can be realized and contact laser probe complementary probe, laser scanner accuracy of 0.05mm, scanning probe contact accuracy of 0.02 mm. Another German company GOM ATOS portable scanners, Japan Rolands PIX-30, PIX-4 desktop scanner and the United Kingdom Taylor Hopsons TALYSCAN150 multi-sensor, respectively Three-dimensional scanner with high speed, low-cost and functional composite and so on. (2) CNC EDM Japan Sodick linear motor servo drive using the companys AQ325L, AQ550LLS-WEDM have driven fast response, transmission and high positioning accuracy, the advantages of small thermal deformation. Switzerland Chanmier company NCEDM with 桂林电子科技大学毕业设计（论文）外文翻译原文 第 12 页 共 28 页 P-E3 adaptive control, PCE energy control and automatic programming expert systems. Others also used the powder mixed EDM machining technology, micro-finishing pulse power and fuzzy control (FC) technologies. (3) high-speed milling machine (HSM) Milling is an important means of cavity mold. The low-temperature high-speed milling with the workpiece, cutting force is small, smooth processing, processing quality, processing efficiency (for the general milling process 5 to 10 times) and can process hard materials (60HRC) and many other advantages. Thus in the mold processing more and more attention. Ruishikelang company UCP710-type five-axis machining center, machine tool positioning accuracy up to 8m, home-made closed-loop vector control spindle with a maximum speed 42000r/min. Italy RAMBAUDIs high-speed milling, the processing range of up to 2500mm 5000mm 1800mm, speed up 20500r/min, cutting feed speed of 20m/min. HSM generally used large, medium-sized mold, such as motor cover mold, die casting mold, large plastic surface machining, the surface precision up to 0.01mm. 4. 3 rapid economic modeling techniques Shorten the product development cycle is an effective means of market competition to win one. Compared with the traditional mold process, fast economic modeling technology is a short molding cycle, the characteristics of low cost, precision, and life can meet the production needs, overall economic efficiency is more significant in the mold manufacturing technology, specifically the following main technology. (1) rapid prototyping and manufacturing (RPM). It consists of three-dimensional laser lithography (SLA)； laminated profile manufacturing (LOM)； laser powder sintering prototyping (SLS)； Fused Deposition Molding (FDM) and three-dimensional printing forming technology (3D-P) and so on. (2) the surface forming tooling. It refers to the use of spray, chemical corrosion, electroforming and new method for the formation of the cavity surface and a fine pattern technology. (3) Casting forming tooling. There are bismuth tin alloy tooling, zinc alloy tooling, resin composite forming technology and silicon rubber mold molding technology. (4) cold extrusion mold technology and ultra-molded shapes. (5) multi-point forming technology. (6) KEVRON steel blanking blanking tooling. (7) mold blank rapid manufacturing technology. Mainly dry sand Mold Casting, Vacuum Mold Casting, Resin Sand Mold Casting Lost Wax Casting, and other technologies. 桂林电子科技大学毕业设计（论文）外文翻译原文 第 13 页 共 28 页 (8) Other aspects of technology. Such as the use of nitrogen gas spring pressure side, discharge, quick die technology, stamping unit technology, and cutting edge technology and solid surfacing edge inserts die casting technology. 4.4 mold materials and surface treatment technology developed rapidly Industry to the level of mold, material application is the key. Due to improper selection and use of materials, causing premature die failure, which accounts for more than 45% failure die.In the mold material, commonly used cold work tool steel with CrWMn, Cr12, Cr12MoV and W6Mo5Cr4V2, flame hardened steel (such as Japan, AUX2, SX105V (7CrSiMnMoV), etc.； used a new type of hot work die steel American H13, Sweden QRO80M, QRO90SUPREME, etc.； used a pre-hardened plastic mold steel (such as the U.S. P20), age-hardening steel (such as the U.S. P21, Japan NAK55, etc.), heat treatment hardened steel (such as the United States, D2, Japan, PD613, PD555, Sweden wins the White 136, etc.), powder die steel (such as Japan KAD18 and KAS440), etc.； panel drawing die used HT300, QT60-2, Mo-Cr, Mo-V cast iron, large-scale mold with HT250. more regular use of Precision Die Hard Steel Results YG20 and other alloys and carbide. in the mold surface treatment, the main trends are: the infiltration of a single element to the multi-element penetration, complex permeability (such as TD method) development； by the general diffusion to the CVD, PVD, PCVD, ion penetration , the direction of ion implantation, etc.； can use the coating are: TiC, TiN, TiCN, TiAlN, CrN, Cr7C3, W2C, etc., while heat from the air treatment means to the development of vacuum heat treatment. In addition, the current strengthening of the laser, glow plasma Nitriding and electroplating (plating) enhanced anti-corrosion technologies are also more and more attention. 4.5 mold industry new techniques, new ideas and new models have been gradually recognized In the forming process, the main function of composite stamping die, superplastic forming, plastic precision molding technology, plastic mold gas-assisted injection technology and hot runner technology, high-pressure injection molding technology. On the other hand, with the continuous development of advanced manufacturing technology and raise the level of mold industry as a whole, in the mold industry, there are some new design, production, management ideas and models. Concrete are: to adapt to the characteristics of mold-piece production flexible manufacturing technologies； to create the best management and effective teamwork, lean production； to enhance rapid response capabilities of Concurrent Engineering, Virtual Manufacturing and global agile manufacturing, manufacturing of new production networks philosophy； extensive use of standard parts common parts of the division of work 桂林电子科技大学毕业设计（论文）外文翻译原文 第 14 页 共 28 页 mode of production； meet the environmental requirements of sustainable development and green design and manufacturing. 5 Filling simulation of the melt 5.1 Mathematical modeling In order to simulate the use of an SL mold in the injection molding process, an iterative method is proposed. Different software modules have been developed and used to accomplish this task. The main assumption is that temperature and load boundary conditions cause significant distortions in the SL mold. The simulation steps are as follows: 1)The part geometry is modeled as a solid model, which is translated to a file readable by the flow analysis package. 2)Simulate the mold-filling process of the melt into a photopolymer mold, which will output the resulting temperature and pressure profiles. 3)Structural analysis is then performed on the photopolymer mold model using the thermal and load boundary conditions obtained from the previous step, which calculates the distortion that the mold undergo during the injection process. 4)If the distortion of the mold converges, move to the next step. Otherwise, the distorted mold cavity is then modeled (changes in the dimensions of the cavity after distortion), and returns to the second step to simulate the melt injection into the distorted mold. 5)The shrinkage and warpage simulation of the injection molded part is then applied, which calculates the final distortions of the molded part. In above simulation flow, there are three basic simulation modules. 5.2 Filling simulation of the melt 5.2.1 Mathematical modeling Computer simulation techniques have had success in predicting filling behavior in extremely complicated geometries. However, most of the current numerical implementation is based on a hybrid finite-element/finite-difference solution with the middleplane model. The application process of simulation packages based on this model is illustrated in Fig. 2-1. However, unlike the surface/solid model in mold-design CAD systems, the so-called middle-plane (as shown in Fig. 2-1b) is an imaginary arbitrary planar geometry at the middle of the cavity in the gap-wise direction, which should bring about great inconvenience in applications. For example, surface models are commonly used in current RP systems (generally STL file format), so secondary modeling is unavoidable when using simulation 桂林电子科技大学毕业设计（论文）外文翻译原文 第 15 页 共 28 页 packages because the models in the RP and simulation systems are different. Considering these defects, the surface model of the cavity is introduced as datum planes in the simulation, instead of the middle-plane. According to the previous investigations 46, fillinggoverning equations for the flow and temperature field can be written as: where x, y are the planar coordinates in the middle-plane, and z is the gap-wise coordinate； u, v,w are the velocity components in the x, y, z directions； u, v are the average whole-gap thicknesses； and , ,CP (T), K(T) represent viscosity, density, specific heat and thermal conductivity of polymer melt, respectively. Fig.2-1 ad. Schematic procedure of the simulation with middle-plane model. a The 3-D surface model b The middle-plane model c The meshed middle-plane model d The display of the simulation result In addition, boundary conditions in the gap-wise direction can be defined as: where TW is the constant wall temperature (shown in Fig. 2a). Combining Eqs. 14 with Eqs. 56, it follows that the distributions of the u, v, T, P at z coordinates should be symmetrical, with the mirror axis being z = 0, and consequently the u, v averaged in half-gap thickness is equal to that averaged in wholegap thickness. Based on this characteristic, we can divide the whole cavity into two equal parts in the gap-wise direction, as described by Part I and Part II in Fig. 2b. At the same time, triangular finite elements are generated in the surface(s) of the cavity (at z = 0 in Fig. 2b), instead of the middle-plane (at z = 0 in Fig. 2a). Accordingly, finite-difference increments in the gapwise direction are 桂林电子科技大学毕业设计（论文）外文翻译原文 第 16 页 共 28 页 employed only in the inside of the surface(s) (wall to middle/center-line), which, in Fig. 2b, means from z = 0 to z = b. This is single-sided instead of two-sided with respect to the middle-plane (i.e. from the middle-line to two walls). In addition, the coordinate system is changed from Fig. 2a to Fig. 2b to alter the finite-element/finite-difference scheme, as shown in Fig. 2b. With the above adjustment, governing equations are still Eqs. 14. However, the original boundary conditions in the gapwise direction are rewritten as: Meanwhile, additional boundary conditions must be employed at z = b in order to keep the flows at the juncture of the two parts at the same section coordinate 7: where subscripts I, II represent the parameters of Part I and Part II, respectively, and Cm-I and Cm-II indicate the moving free melt-fronts of the surfaces of the divided two parts in the filling stage. It should be noted that, unlike conditions Eqs. 7 and 8, ensuring conditions Eqs. 9 and 10 are upheld in numerical implementations becomes more difficult due to the following reasons: 1)The surfaces at the same section have been meshed respectively, which leads to a distinctive pattern of finite elements at the same section. Thus, an interpolation operation should be employed for u, v, T, P during the comparison between the two parts at the juncture. 2)Because the two parts have respective flow fields with respect to the nodes at point A and point C (as shown in Fig. 2b) at the same section, it is possible to have either both filled or one filled (and one empty). These two cases should be handled separately, averaging the operation for the former, whereas assigning operation for the latter. 3)It follows that a small difference between the melt-fronts is permissible. That allowance can be implemented by time allowance control or preferable location allowance control of the melt-front nodes. 4)The boundaries of the flow field expand by each melt-front advancement, so it is necessary to check the condition Eq. 10 after each change in the melt-front. 5)In view of above-mentioned analysis, the physical parameters at the nodes of the same section should be compared and adjusted, so the information describing finite elements of the same section should be prepared before simulation, that is, the matching operation among the elements should be preformed. 桂林电子科技大学毕业设计（论文）外文翻译原文 第 17 页 共 28 页 Fig. 2a,b. Illustrative of boundary conditions in the gap-wise direction a of the middle-plane model b of the surface model 5.2.2 Numerical implementation Pressure field. In modeling viscosity , which is a function of shear rate, temperature and pressure of melt, the shear-thinning behavior can be well represented by a cross-type model such as: where n corresponds to the power-law index, and characterizes the shear stress level of the transition region between the Newtonian and power-law asymptotic limits. In terms of an Arrhenius-type temperature sensitivity and exponential pressure dependence, 0(T, P) can be represented with reasonable accuracy as follows: Equations 11 and 12 constitute a five-constant (n, , B, Tb, ) representation for viscosity. The shear rate for viscosity calculation is obtained by: Based on the above, we can infer the following filling pressure equation from the governing Eqs. 14: where S is calculated by S = b0/(bz)2 dz. Applying the Galerkin method, the pressure finite-element equation is deduced as: 桂林电子科技大学毕业设计（论文）外文翻译原文 第 18 页 共 28 页 where l_ traverses all elements, including node N, and where I and j represent the local node number in element l_ corresponding to the node number N and N_ in the whole, respectively. The D(l_) ij is calculated as follows: where A(l_) represents triangular finite elements, and L(l_) i is the pressure trial function in finite elements. Temperature field. To determine the temperature profile across the gap, each triangular finite element at the surface is further divided into NZ layers for the finite-difference grid. The left item of the energy equation (Eq. 4) can be expressed as: where TN, j,t represents the temperature of the j layer of node N at time t. The heat conduction item is calculated by: where l traverses all elements, including node N, and i and j represent the local node number in element l corresponding to the node number N and N_ in the whole, respectively. The heat convection item is calculated by: For viscous heat, it follows that: Substituting Eqs. 1720 into the energy equation (Eq. 4), the temperature equation becomes: 桂林电子科技大学毕业设计（论文）外文翻译原文 第 19 页 共 28 页 5.3 Structural analysis of the mold The purpose of structural analysis is to predict the deformation occurring in the photopolymer mold due to the thermal and mechanical loads of the filling process. This model is based on a three-dimensional thermoelastic boundary element method (BEM). The BEM is ideally suited for this application because only the deformation of the mold surfaces is of interest. Moreover, the BEM has an advantage over other techniques in that computing effort is not wasted on calculating deformation within the mold. The stresses resulting from the process loads are well within the elastic range of the mold material. Therefore, the mold deformation model is based on a thermoelastic formulation. The thermal and mechanical properties of the mold are assumed to be isotropic and temperature independent. Although the process is cyclic, time-averaged values of temperature and heat flux are used for calculating the mold deformation. Typically, transient temperature variatio ns within a mold have been restricted to regions local to the cavity surface and the nozzle tip 8. The transients decay sharply with distance from the cavity surface and generally little variation is observed beyond distances as small as 2.5 mm. This suggests that the contribution from the transients to the deformation at the mold block interface is small, and therefore it is reasonable to neglect the transient effects. The steady state temperature field satisfies Laplaces equation 2T = 0 and the time-averaged boundary conditions. The boundary conditions on the mold surfaces are described in detail by Tang et al. 9. As for the mechanical boundary conditions, the cavity surface is subjected to the melt pressure, the surfaces of the mold connected to the worktable are fixed in space, and other external surfaces are assumed to be stress free. The derivation of the thermoelastic boundary integral formulation is well known 10. It is given by: where uk, pk and T are the displacement, traction and temperature, represent the thermal expansion coefficient and Poissons ratio of the material, and r = |yx|. clk(x) is the 桂林电子科技大学毕业设计（论文）外文翻译原文 第 20 页 共 28 页 surface coefficient which depends on the local geometry at x, the orientation of the coordinate frame and Poissons ratio for the domain 11. The fundamental displacement ulk at a point y in the xk direction, in a three-dimensional infinite isotropic elastic domain, results from a unit load concentrated at a point x acting in the xl direction and is of the form: where lk is the Kronecker delta function and is the shear modulus of the mold material. The fundamental traction plk , measured at the point y on a surface with unit normal n, is: Discretizing the surface of the mold into a total of N elements transforms Eq. 22 to: where n refers to the nth surface element on the domain. Substituting the appropriate linear shape functions into Eq. 25, the linear boundary element formulation for the mold deformation model is obtained. The equation is applied at each node on the discretized mold surface, thus giving a system of 3N linear equations, where N is the total number of nodes. Each node has eight associated quantities: three components of displacement, three components of traction, a temperature and a heat flux. The steady state thermal model supplies temperature and flux values as known quantities for each node, and of the remaining six quantities, three must be specified. Moreover, the displacement values specified at a certain number of nodes must eliminate the possibility of a rigid-body motion or rigid-body rotation to ensure a non-singular system of equations. The resulting system of equations is assembled into a integrated matrix, which is solved with an iterative solver. 5.4 Shrinkage and warpage simulation of the molded part Internal stresses in injection-molded components are the principal cause of shrinkage and warpage. These residual stresses are mainly frozen-in thermal stresses due to inhomogeneous 桂林电子科技大学毕业设计（论文）外文翻译原文 第 21 页 共 28 页 cooling, when surface layers stiffen sooner than the core region, as in free quenching. Based on the assumption of the linear thermo-elastic and linear thermo-viscoelastic compressible behavior of the polymeric materials, shrinkage and warpage are obtained implicitly using displacement formulations, and the governing equations can be solved numerically using a finite element method. With the basic assumptions of injection molding 12, the components of stress and strain are given by: The deviatoric components of stress and strain, respectively, are given by Using a similar approach developed by Lee and Rogers 13 for predicting the residual stresses in the tempering of glass, an integral form of the viscoelastic constitutive relationships is used, and the in-plane stresses can be related to the strains by the following equation: Where G1 is the relaxation shear modulus of the material. The dilatational stresses can be related to the strain as follows: Where K is the relaxation bulk modulus of the material, and the definition of and is: If (t) = 0, applying Eq. 27 to Eq. 29 results in: Similarly, applying Eq. 31 to Eq. 28 and eliminating strain xx(z, t) results in: 桂林电子科技大学毕业设计（论文）外文翻译原文 第 22 页 共 28 页 Employing a Laplace transform to Eq. 32, the auxiliary modulus R() is given by: Using the above constitutive equation (Eq. 33) and simplified forms of the stresses and strains in the mold, the formulation of the residual stress of the injection molded part during the cooling stage is obtain by: Equation 34 can be solved through the application of trapezoidal quadrature. Due to the rapid initial change in the material time, a quasi-numerical procedure is employed for evaluating the integral item. The auxiliary modulus is evaluated numerically by the trapezoidal rule. For warpage analysis, nodal displacements and curvatures for shell elements are expressed as: where k is the element stiffness matrix, Be is the derivative operator matrix, d is the displacements, and re is the element load vector which can be evaluated by: The use of a full three-dimensional FEM analysis can achieve accurate warpage results, however, it is cumbersome when the shape of the part is very complicated. In this paper, a twodimensional FEM method, based on shell theory, was used because most injection-molded parts have a sheet-like geometry in which the thickness is much smaller than the other dimensions of the part. Therefore, the part can be regarded as an assembly of flat elements to predict warpage. Each three-node shell element is a combination of a constant strain triangular element (CST) and a discrete Kirchhoff triangular element (DKT), as shown in Fig. Thus, the warpage can be separated into plane-stretching deformation of the CST and 桂林电子科技大学毕业设计（论文）外文翻译原文 第 23 页 共 28 页 plate-bending deformation of the DKT, and correspondingly, the element stiffness matrix to describe warpage can also be divided into the stretching-stiffness matrix and bending-stiffness matrix. Fig. 3ac. Deformation decomposition of shell element in the local coordinate system. a In-plane stretching element b Plate-bending element c Shell element 6 Experimental validation To assess the usefulness of the proposed model and developed program, verification is important. The distortions obtained from the simulation model are compared to the ones from SL injection molding experiments whose data is presented in the literature 8. A common injection molded part with the dimensions of 36366 mm is considered in the experiment, as shown in Fig. 4. The thickness dimensions of the thin walls and rib are both 1.5 mm； and polypropylene was used as the injection material. The injection machine was a production level ARGURY Hydronica 320-210-750 with the following process parameters: a melt temperature of 250 C； an ambient temperature of 30 C； an injection pressure of 13.79 MPa； an injection time of 3 s； and a cooling time of 48 s. The SL material used, Dupont SOMOSTM 6110 resin, has the ability to resist temperatures of up to 300 C temperatures. As mentioned above, thermal conductivity of the mold is a major factor that differentiates between an SL and a traditional mold. Poor heat transfer in the mold would produce a 桂林电子科技大学毕业设计（论文）外文翻译原文 第 24 页 共 28 页 non-uniform temperature distribution, thus causing warpage that distorts the completed parts. For an SL mold, a longer cycle time would be expected. The method of using a thin shell SL mold backed with a higher thermal conductivity metal (aluminum) was selected to increase thermal conductivity of the SL mold. Fig. 4. Experimental cavity model Fig. 5. A comparison of the distortion variation in the X direction for different thermal conductivity； where “Experimental”, “present”, “three-step”, and “conventional” mean the results of the experimental, the presented simulation, the three-step simulation process and the conventional injection molding simulation, respectively. Fig. 6. Comparison of the distortion variation in the Y direction for different thermal conductivities 桂林电子科技大学毕业设计（论文）外文翻译原文 第 25 页 共 28 页 Fig. 7. Comparison of the distortion variation in the Z direction for different thermal conductivities Fig. 8. Comparison of the twist variation for different thermal conductivities For this part, distortion includes the displacements in three directions and the twist (the difference in angle between two initially parallel edges). The validation results are shown in Fig. 5 to Fig. 8. These figures also include the distortion values predicted by conventio nal injection molding simulation and the three-step model reported in 3. 桂林电子科技大学毕业设计（论文）外文翻译原文 第 26 页 共 28 页 7 Conclusions In this paper, an integrated model to accomplish the numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. For verification, an experiment is also carried out with an RPfabricated SL mold. It is seen that a conventional simulation using current injection molding software breaks down for a photopolymer mold. It is assumed that this is due to the distortion in the mold caused by the temperature and load conditions of injection. The t