Rapid prototyping technology, also known as rapid prototyping manufacturing technology, was born in the late 1980s and is considered to be a major achievement in the manufacturing field in the past 20 years.It setsmechanical engineering、CAD、reverse engineering Technology, layered manufacturing technology, numerical control technology, material science, and laser technology can automatically, directly, quickly, and accurately transform design ideas into prototypes with certain functions or directly manufacture parts, thus providing an efficient and low-cost means for prototype production of parts, verification of new design ideas, and so on.
Chinese name
Rapid prototyping technology
Foreign name
Rapid Prototyping Manufacturing
Abbreviation
RPM technology
Born in
Late 1980s
Advantages
Shorten development cycle and reduce production cost
Since the 1990s,manufacturing industryThe external situation has undergone fundamental changes.The individualization and variability of user needs force enterprises to gradually abandon the production mode of small variety and large batch, which is characterized by "scale efficiency first", and then adopt the modern production mode of multi variety, small batch and order based production.At the same time, the globalization and integration of the market require enterprises to have a high degree of sensitivity. In the face of the rapidly changing market environment, enterprises should constantly and rapidly develop new products, change passive adaptation to users to active guidance of the market, so as to ensure that enterprises can remain invincible in the competition.It can be seen that in this era, the focus of market competition will shift to speed. Enterprises that can quickly provide products with higher performance/price ratio will have stronger comprehensive competitiveness.Rapid prototyping technologyIt is an important branch of advanced manufacturing technology. It has made great breakthroughs in both manufacturing ideas and implementation methods. Rapid prototyping technology can be used to quickly evaluate and modify product design, and automatically and quickly transform the design into prototype products with corresponding structures and functions or directly manufacture parts, thus greatly shortening the development cycle of new products,Reduce product development costs, enable enterprises to quickly respond to market demand, and improve the market competitiveness of products and the comprehensive competitiveness of enterprises[1]。
characteristic
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1. The materials used to manufacture the prototype are unlimited, including various metals andNon metallic materialsCan be used;
2. High reproducibility and interchangeability of prototype;
3. The manufacturing process has nothing to do with the geometric shape of the manufacturing prototype, so it is superior in machining complex surfaces;
4. The processing cycle is short, the cost is low, and the cost has nothing to do with the complexity of the product. The general manufacturing cost is reduced by 50%, and the processing cycle is saved by more than 70%;
5. High technology integration, which can realize the integration of design and manufacturing.
Background
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1. With the formation of global market integration, the competition in manufacturing industry is very fierce, and the speed of product development has increasingly become the main contradiction.In this case, the School of Machinery, Xi'an Jiaotong University, rapid prototypingNational Engineering Research CenterThe capability (cycle and cost) of independent rapid product development (rapid design and rapid tooling) of the Rapid Prototyping Engineering Research Center of the Ministry of Education has become the strength foundation of global competition in manufacturing industry.
2. In order to meet the ever-changing user needs, the manufacturing industry requires strong flexibility in manufacturing technology, which can be produced in small batches or even single pieces without increasing the cost of products.Therefore, the speed of product development and the flexibility of manufacturing technology are very critical.
3. From the perspective of technological development, the development and popularization of computer science, CAD technology, material science and laser technology have laid a technological material foundation for the emergence of new manufacturing technology.
Fundamentals
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Rapid prototyping technology is a technology that uses different methods to stack materials based on the principle of discrete and stacking under the control of computer to finally complete the forming and manufacturing of parts.
1. From the forming point of view, the part can be regarded as the superposition of "points" or "faces".The geometric information of "point" or "face" is obtained from the CAD electronic model, and then combined with the information of forming process parameters to control the materials to stack parts regularly and accurately from point to face and from face to body.
2. From the perspective of manufacturing, it generates 3D geometric information of parts according to CAD modeling, controls multidimensional systems, and stacks materials layer by layer through laser beam or other methods to form prototypes or parts.
Classification of molding
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Remove molding
The removal molding is a processing method that uses the separation method to separate part of the materials from the matrix in an orderly manner as required.The traditional turning, milling, creating, grinding and other processing methods are all removal molding.Removal molding is the main molding method in manufacturing industry.
Add molding
Additive molding is a molding method that uses various mechanical, physical, chemical and other means to achieve the design requirements of parts by orderly adding materials.Rapid prototyping technology is a typical representative of addition molding. It breaks through the traditional molding method in thought, and can rapidly manufacture parts of any complexity. It is a very promising new manufacturing technology.
Forced molding
Forced forming is a method that uses the formability (such as plasticity) of materials to form under specific peripheral constraints (boundary constraints or external force constraints).Traditional casting, forging and powder metallurgy belong to forced forming.Forced forming has not yet fully realized computer control, and is mostly used for blank forming, special material forming, etc.
Growth molding
Growth molding is a method of molding using the activity of biological materials. The development of biological individuals in nature belongs to growth molding, and "cloning" technology is a growth molding method in an artificial system.With the development of active materials, bionics, biochemistrylife sciencesThis forming method will be greatly developed and applied.
application
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Continuously improving the application level of RP technology is an important aspect to promote the development of RP technology.The rapid prototyping technology has been widely used in the fields of industrial modeling, machinery manufacturing, aerospace, military, architecture, film and television, household appliances, light industry, medicine, archaeology, culture and art, sculpture, jewelry, etc.And with the development of this technology itself, its application fields will continue to expand.The practical application of RP technology mainly focuses on the following aspects:
1. The application of rapid prototyping technology in the process of new product modeling design has established a new product development mode for the design and development personnel of industrial products.Using RP technology can quickly, directly and accurately transform the design idea into a physical model with certain functions, which not only shortens the development cycle, but also reduces the development cost, and also enables enterprises to take the lead in the fierce market competition.
2. Application in the field of mechanical manufacturing Due to the characteristics of RP technology, it has been widely used in the field of mechanical manufacturing, mostly for manufacturing single pieces and small batchesmetal partsManufacturing of.Some special and complex parts can be directly formed by RP technology with low cost and short cycle because they only need to be produced in a single piece or in small batches of less than 50 pieces.
3. Rapid tooling manufacturing traditional mold production time is long and cost is high.The combination of rapid prototyping technology and traditional mold manufacturing technology can greatly shorten the development cycle of mold manufacturing, improve productivity, and is an effective way to solve the weak link in mold design and manufacturing.The application of rapid prototyping technology in mold manufacturing can be divided into direct mold making and indirect mold making. Direct mold making means that the RP technology is used to directly stack and manufacture the mold. Indirect mold making means that the rapid prototyping parts are made first, and then the required mold is copied from the parts.
4. In the application of medical field, people have more research on the application of RPM technology in the medical field.Based on medical image data, making human organ models using RP technology has great application value for surgery.
5. The application in the field of culture and art In the field of culture and art, rapid prototyping manufacturing technology is mostly used for artistic creation, cultural relic replication, digital sculpture, etc.
6. OnAerospace technologyApplications in aerospace, aerodynamicsGround simulation experiment, i.eWind tunnel testIt is an essential part of designing the space shuttle system with advanced performance.The model used in this experiment has complex shape, high precision requirements, and streamline characteristics. RP technology is used to automatically complete the solid model by RP equipment according to the CAD model, which can well ensure the quality of the model.
7. In the application of household appliances industry, rapid prototyping system has been popularized and applied to a large extent in the domestic household appliances industry, making many household appliances enterprises take the lead in the country, and have successively adopted rapid prototyping system to develop new products, which has received good results.Rapid prototyping technology is widely used. It is believed that with the continuous maturity and improvement of rapid prototyping manufacturing technology, it will be promoted and applied in more and more fields[1]。
development direction
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From the research and application status of RP technology, the further research and development work of rapid prototyping technology mainly includes the following aspects:
1. Develop high-performance rapid prototyping materials, such as low-cost, easy to form, small deformation, high strength, durable and pollution-free forming materials.
2. Improve the processing speed of RP system and develop the process method of concurrent manufacturing.
3. Improve the reliability of the rapid prototyping system, improve its productivity and ability to make large parts, optimize the equipment structure, especially improve the precision, surface quality, mechanical and physical properties of the formed parts, and provide a basis for further die processing and functional experiments.
4. Develop high-performance RPM software for rapid prototyping.Improve the speed and precision of data processing, research and develop the method of direct slicing of CAD original data, and reduce the precision loss caused by STL format conversion and slicing process.
5. Develop new forming energy sources.
6. Improvement and innovation of rapid prototyping methods and processes.Direct metal forming technology will become another hotspot in the future research and application.
7. Research on the integration of rapid prototyping technology with CAD, CAE, RT, CAPP, CAM, high-precision automatic measurement and reverse engineering.
8. Improve the research on networked services and realize remote control.
Problems
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Process problems
The basis of rapid prototyping is the principle of layered stacking. However, what materials are used for layered stacking and how to do it are of great research value.Therefore, in addition to the above common layered superposition forming methods, some new layered superposition forming methods are being studied and developed in order to further improve the performance of parts, improve the forming accuracy and forming efficiency.
Material problems
The research of forming materials has always been a hot issue. The properties of rapid prototyping materials should meet the following requirements: ① it is conducive to rapid and accurate processing; ②The materials used for the rapid prototyping system to directly manufacture functional parts should be close to the requirements of the end use of the parts for strength, stiffness, moisture resistance, thermal stability, etc.; ③It is conducive to the follow-up processing of rapid molding.The development of new RP materials, especially composite materials, such as nano materials, heterogeneous materials, materials difficult to make by other methods, is still the direction of efforts.
Accuracy problem
The precision of rapid prototyping parts is generally at the level of ± 0.1 mm, especially in the height direction.The basic principle of rapid prototyping technology determines that the process is difficult to achieve the surface quality and precision indicators that traditional machining hasMachining methodIntegration and complementary advantages are one of the important methods to improve the precision of rapid prototyping.
Software problems
The layered slicing algorithm used by the rapid prototyping system is based on the STL file format for conversion, that is, a series of triangular meshes are used to approximate the data file of the CAD model. However, this data representation method has many defects, such as the triangular meshes will appear some gaps, resulting in data loss, and the step effect caused by plane layering,It also reduces the surface quality and forming accuracy of parts, and should focus on developing new model slicing methods, such as feature based model direct slicing method and surface layering method, that is, without STL format file conversion, directly slice the CAD model to obtain the profile of each section of the model, or directly drive the rapid prototyping system using the slicing data obtained by reverse engineering layer by layer,Thus, the error caused by triangular surface approximation is reduced, and the forming precision and speed are improved.
energy problem
The energy used in rapid prototyping technology includes light energy, heat energy, chemical energy, mechanical energy, etc.The energy density, the fineness of energy control, and the quality of molding and processing need to be further improved.
Problems in application field
The application field of the existing rapid prototyping technology mainly lies in the development of new products. Its main role is to shorten the development cycle and obtain market feedback as soon as possible.
Due to the great attraction of rapid prototyping technology, not only the industry attaches great importance to it, but also many other industries are committed to its application and promotion. After its technology has made progress in the direction of higher precision and better material performance, it can consider adding applications in many fields such as biomedicine, archaeology, cultural relics, art design, building molding, etc. to form high-efficiencyHigh quality and high-precision replication process system[2]。
