Rapid Prototyping Technology
Rapid Prototyping Technology, also known as Rapid Prototyping Manufacturing (RapidPrototypingManufacturing, or RPM) technology, was born in the late 1980s, is based on the material stacking method of a new and high tech manufacturing technology, which is considered to be a major achievement in the field of manufacturing in the past 20 years. It combines mechanical engineering, CAD, reverse engineering technology, layered manufacturing technology, CNC technology, material science, laser technology, and can automatically, directly, quickly and accurately transform the design ideas into prototypes with certain functions or directly manufacture parts, thus providing an efficient and low-cost means of realization for the prototyping of parts and the calibration of new design ideas. That is, rapid prototyping technology is the use of three-dimensional CAD data, through the rapid prototyping machine, layer upon layer of material stacked into a solid prototype.
Features of rapid prototyping technology
(1) the material used to manufacture the prototype is not limited, a variety of metal and non-metallic materials can be used;
(2) the prototype of the reproducibility, interchangeability is high;
(3) the manufacturing process has nothing to do with the manufacturing of the geometry of the prototype, the processing of complex curved surfaces is more superior;
(4) the short processing period
(5) high degree of technological integration, can realize the integration of design and manufacturing;
Background of RP technology
(1) With the formation of the integration of the global market, the manufacturing industry is very competitive, and the speed of product development is increasingly becoming the main contradiction. The main contradiction. In this case, the ability (cycle time and cost) of independent rapid product development (rapid design and rapid tooling) has become the basis of the strength of global competition in the manufacturing industry.
(2) manufacturing industry in order to meet the increasingly changing user needs, the requirements of manufacturing technology has a strong flexibility, can be produced in small batches or even a single piece without increasing the cost of the product. Therefore, the speed of product development and the flexibility of manufacturing technology is very critical.
(3) from the perspective of technological development, computer science, CAD technology, materials science, laser technology development and popularization for the generation of new manufacturing technology has laid a technical and material basis.
Basic principle of RP technology
Rapid prototyping technology is under the control of the computer, based on the principle of discrete, stacked using different methods of stacking materials, and ultimately complete the forming of parts and manufacturing technology.
1, from the molding point of view, parts can be regarded as ? point? or? surface? The superposition. Discrete from the CAD electronic model to get ? points? or? surface? Geometric information, and then combined with the forming process parameter information, control the material regularly and accurately from point to surface, from surface to body stacking parts.
2, from the manufacturing point of view, it is based on CAD modeling to generate parts of three-dimensional geometric information, control of multi-dimensional systems, through the laser beam or other methods of material layer by layer stacking and the formation of prototypes or parts.
Types of RP technology
In the last decade or so, with the formation of the integration of the global market, the manufacturing industry is very competitive. In particular, the rapid prevalence of computer technology and the wide application of CAD/CAM technology, making the RP technology has been an extraordinary high-speed development, showing a strong vitality and broad application prospects. Rapid prototyping technology development so far, with its technology of high integration, high flexibility, high speed and has been rapid development. At present, there are dozens of rapid prototyping process methods, of which the main process has four basic types: light-curing molding method, layered entity manufacturing method, selective laser sintering method and fused deposition manufacturing method.
1. Light-curing molding
SLA (StereolithographyApparatus) process, also known as light modeling, stereolithography and stereoscopic printing, the process is a liquid photosensitive resin as a material filled with liquid tank, computer-controlled laser beam tracking layer cross-section trajectory and irradiation of the liquid resin in the liquid tank, and make this layer of resin Curing, after the elevator down a layer of height, has been molded on the level of a layer of resin covered, and then a new layer of scanning, the new cured layer firmly adhered to the previous layer, and so on and so forth until the entire part manufacturing is complete, to get a three-dimensional solid model. The process is characterized by: high accuracy of the prototype parts, parts of good strength and hardness, can produce a particularly complex shape of the hollow parts, the production of the model of good flexibility, can be disassembled and assembled at will, is the ideal method of indirect mold making. Disadvantages are the need for support, resin shrinkage will lead to a decline in precision, in addition to light-curing resin has a certain degree of toxicity and does not meet the development trend of green manufacturing, etc..
2. Layered Object Manufacturing
LOM (LaminatedObjectManufacturing) process or known as the laminated object manufacturing, the principle of the process is based on the parts layered geometric information cutting foil and paper, etc., will be obtained by bonding the layers of pieces into a three-dimensional entity. The process is: first lay a layer of foil, and then use CO, laser under computer control to cut out the contour of the layer, non-part part of all the chopping in order to facilitate the removal. When the layer is completed, and then lay a layer of foil, with a roller and heat, in order to solidify the adhesive, so that the new layer firmly bonded to the body has become a form, and then cut the contour of the layer, and so on and so forth until the completion of the process, and finally remove the shredded portion of the part to get a complete part. The process is characterized by reliable work, good model support, low cost and high efficiency. The disadvantage is that the pre- and post-processing is time-consuming and labor-intensive, and it is not possible to manufacture hollow structural parts.
3. Selective Laser Sintering
SLS (SelectiveLaserSintering) process, often using materials such as metal, ceramics, ABS plastic and other materials as a molding material powder. The process is: the first layer of powder on the table, under computer control with a laser beam selective sintering (parts of the hollow part is not sintered, still powder material), the sintered part will be cured together to form a solid part of the parts. After one layer is completed, the next layer is applied and the new layer is firmly sintered to its predecessor. After all sintering is complete, the excess powder is removed and the sintered part is obtained. The process is characterized by a wide range of materials, not only plastic parts, but also ceramic, metal, wax and other materials. The modeling accuracy is high and the strength of the prototype is high, so the prototype can be used for functional testing or assembly simulation.
4. Fused Deposition Molding
FDM (FusedDepositionManufacturing) process is also known as Fused Filament Deposition Manufacturing (FDM) process is based on the thermoplastic molding material filaments, the material filaments through the heater's extruder head melted into a liquid by the computer control of the extruder head along the contour of each cross-section of the part accurate movement, so that the The melted thermoplastic material filament is extruded through a nozzle, covering the constructed part and solidifying rapidly in a very short time to form a layer of material. Afterwards, the extrusion head is moved axially upwards for a small distance to build the next layer of material. This builds up layer by layer from bottom to top to form a solid model or part. The process is characterized by simplicity of use and maintenance, low cost, speed, with prototypes of average complexity taking only a few hours to form, and lack of contamination.
In addition to the four most familiar technologies mentioned above, there are many technologies that have also been practical, such as three-dimensional printing technology, light shielding process, direct shell method, direct sintering technology, holographic interference manufacturing.
Application of RP technology
Continuously improving the application level of RP technology is an important aspect of promoting the development of RP technology. At present, rapid prototyping technology has been widely used in industrial modeling, mechanical manufacturing, aerospace, military, construction, film and television, home appliances, light industry, medicine, archaeology, culture and art, sculpture, jewelry and other fields. And with the development of this technology itself, its application areas will continue to expand. the practical application of RP technology is mainly focused on the following aspects:
(1) in the design process of new product modeling applications rapid prototyping technology for the design and development of industrial products to establish a new model of product development. The use of RP technology can quickly, directly and accurately design ideas into a physical model with certain functions (prototype), which not only shortens the development cycle, but also reduces the development costs, but also allows companies to have a head start in the fierce competition in the market.
(2) in the field of machinery manufacturing applications due to the characteristics of RP technology itself, making it in the field of machinery manufacturing, access to a wide range of applications, mostly used for the manufacture of single-piece, small batch metal parts manufacturing. Some special complex parts, due to only a single piece of production, or less than 50 pieces of small quantities, generally available RP technology directly for molding, low cost, short cycle.
(3) rapid mold manufacturing traditional mold production time is long, high cost. Rapid prototyping technology combined with traditional mold manufacturing technology can greatly shorten the development cycle of mold manufacturing, improve productivity, is an effective way to solve the weak link of mold design and manufacturing. The application of rapid prototyping technology in mold manufacturing can be divided into direct mold making and indirect mold making two kinds, direct mold making refers to the use of RP technology directly stacked to make a mold, indirect mold making is the first production of rapid prototyping parts, and then by the parts copy to get the required mold.
(4) in the field of medical applications in recent years, people on the application of RP technology in the field of medicine more research. Based on medical imaging data, the use of RP technology to produce models of human organs, which has great application value for surgical operations.
(5) Application in the field of culture and art in the field of culture and art, rapid prototyping manufacturing technology is mostly used for art creation, cultural relics reproduction, digital sculpture and so on.
(6) in the field of aerospace technology applications in the field of aerospace, aerodynamics ground simulation experiment (i.e., wind tunnel experiments) is the design of advanced performance of the sky and earth round-trip system (i.e., the space shuttle) is essential to the important links. The model used in this experiment has a complex shape, high precision requirements, and has streamlined characteristics, the use of RP technology, according to the CAD model, by the RP equipment to automatically complete the solid model, can be very good to ensure the quality of the model.
(7) the application of home appliance industry at present, rapid prototyping system in the domestic home appliance industry has been popularized and applied to a large extent, so that many home appliance enterprises in the forefront of the domestic. For example: Guangdong's Midea, Huabao, Kelong; Jiangsu's Chunlan, Little Swan; Qingdao's Haier, etc., have adopted rapid prototyping system to develop new products, and received very good results. Rapid prototyping technology has a wide range of applications, it can be believed that with the continuous maturity and improvement of rapid prototyping manufacturing technology, it will be promoted and applied in more and more fields.
Direction of development of rapid prototyping technology
From the current status of research and application of RP technology, the further research and development of rapid prototyping technology is mainly in the following areas:
(1) Development of rapid prototyping materials with good performance, such as low-cost, easy to form, deformation of small, high-strength, durable and non-polluting forming materials.
(2) Improve the processing speed of RP systems and develop process methods for parallel manufacturing.
(3) Improve the reliability of the rapid prototyping system, increase its productivity and ability to make large parts, optimize the structure of the equipment, in particular, improve the precision, surface quality, mechanical and physical properties of the formed parts, and provide a basis for further mold processing and functional experiments.
(4) Develop high-performance RPM software for rapid forming. Improve the speed and accuracy of data processing, research and development of the use of CAD raw data directly sliced method to reduce the loss of accuracy generated by the STL format conversion and slicing process.
(5) Development of new molding energy.
(6) Improvement and innovation of rapid forming methods and processes. Direct metal forming technology will become the future research and application of another ? a hot spot.
(7) The integration research of rapid prototyping technology with CAD, CAE, RT, CAPP, CAM and high-precision automatic measurement, reverse engineering.
(8) Improve the research of networked services to achieve remote control.
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