Development of rapid prototyping and rapid tooling

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The development of rapid prototyping and rapid tooling technology is summarized in this paper, especially the latest achievements in rapid prototyping system, materials and rapid tooling in the past two years, and the development trend of rapid prototyping and rapid tooling technology is analyzed

key words: rapid prototyping, rapid tooling, technological development

1. Introduction

21 century is an era characterized by knowledge economy and information society. The manufacturing industry is facing the severe challenge of the rapidly changing market in the information society to the requirements of small batch and multiple products. With the internationalization of manufacturing industry, shortening the product development cycle and reducing the investment risk of developing new products have become the key to the survival of enterprises. The rapid prototyping technology, which directly generates three-dimensional objects from computer models, arises from the needs of the rapid development of modern design and modern manufacturing technology. It involves mechanical engineering, automatic control, laser, computer, materials and other disciplines. In recent years, the technology has been rapidly applied in the fields of industrial modeling, manufacturing, architecture, art, medicine, aviation, aerospace, archaeology, film and television. Rapid Prototyping/rapid tooling/rapid manufacturing technology provides an advanced means for enterprises to improve their competitiveness

rapid prototyping (hereinafter referred to as RP) has made great progress in forming system and materials since its inception in the 1980s. It has also promoted the development of rapid tooling (hereinafter referred to as RT) and rapid manufacturing (hereinafter referred to as RM). The middle and late 1990s is the stage of vigorous development of RP technology. In China, Huazhong University of science and technology, Tsinghua University, Xi'an Jiaotong University, Beijing Longyuan company and Nanjing University of Aeronautics and Astronautics took the lead in developing the research, development, promotion and application of RP and related technologies in the early 1990s. By 1999, dozens of imported or domestic RP systems had been running in enterprises, universities, research institutions and rapid prototyping service centers. Under the leadership and support of the Ministry of science and technology of the people's Republic of China, nearly ten "rapid prototyping manufacturing technology productivity promotion centers" have been established to promote the application of RP technology. The 863/cims subject expert group has also included rapid prototyping technology into the development projects of target products. In addition, a considerable number of colleges and universities have included RP technology in the "211" plan. The number of domestic units investing in RP research has increased year by year, and the RP market has initially taken shape

2. Brief history of rapid prototyping technology

rp technology is a manufacturing method that uses materials to pile up parts layer by layer or point by point. The idea of layered manufacturing of three-dimensional objects first appeared in the 19th century, when the manufacturing technology was not developed. As early as 1892, blanthre advocated the hierarchical method to make 3D map models. In 1979, Professor Weixiong Nakagawa of Tokyo University manufactured metal blanking die, forming die and injection mold by using layered technology

the development of lithography technology has played a catalytic role in the emergence of modern RP technology

from the late 1970s to the early 1980s, Bert (1978) of 3M company in the United States, xiunan Xiaoyu (1980) of Japan, Charles LL (1982) of UVP company in the United States and Yoji MARUYA (1983) of Japan independently put forward the concept of RP in different places, that is, a new idea of using selective solidification of continuous layers to generate three-dimensional entities. Charles ll, with the continued support of UVP, completed a complete system called sterolithographyapparatus (SLA) that can automatically build parts. Sla-1 the system was patented in 1986, which is a milestone in RP development

in the same year, Charles ll and the shareholders of UVP established 3D system company together; Subsequently, many concepts and technologies related to rapid prototyping developed and matured in 3D system. At the same time, other forming principles and corresponding forming machines have been developed successfully. In 1984, Michael feygin proposed the method of laminatde object manufacturing (hereinafter referred to as LOM), established helisys company in 1985, and developed the first commercial model lom-1015 around 1990. In 1986, ckaed, a graduate student of Texas University in the United States, put forward the idea of selective laser sintering (SLS), and later formed DTM company. In 1992, scottcrumb developed the SLS based commercial sintering machine. In 1988, scottcrumb put forward the idea of fused deposition modeling (FDM), and in 1992, he developed the first commercial 3D modeler. Since the development of SLA Photoforming technology in the mid-1980s to the late 1990s, there have been more than a dozen different rapid prototyping technologies. In addition to the above-mentioned ones, typical ones are 3DP, SDM, SGC, etc. At present, SLA, LOM, SLS and FDM technologies are relatively mature

3. New development of RP technology

3.1 light curing forming (SLA)

this forming method is a rapid prototyping method with the most in-depth research, the most mature technology and the most widely used in the world. At present, 3D system, EOS, F & S, CMET, d-mec, Teijin Seiki, Mitsui Zosen, Xi'an Jiaotong University and Huazhong University of science and technology are studying SLA methods. The SLA technology of American 3D system company accounts for the largest proportion in the international market. Its equipment has made great progress in technology since the introduction of sla-250 model in 1988. The sla-3500 and sla-5000 models introduced in recent years use semiconductor excited solid-state lasers, with scanning speeds of 2.54m/sec and 5m/sec respectively, and the minimum forming layer thickness of 0.05mm. Compared with the sla-5000 model, the sla-7000 model introduced by the company in 1999, Although the forming volume is roughly the same, the scanning speed is 9.52m/sec, the average forming speed is increased by 4 times, the minimum forming layer thickness is 0.025mm, and the accuracy is doubled

sla molding technology mainly has four series of materials: cibatoolsl series produced by Ciba company, Somos series produced by DuPont company, stereocol series produced by Zeneca company and rpcure series produced by RPC company (Sweden). Cibaoolsl series has the following new varieties: cibaoolsl-5510 for sla-3500. This resin can achieve higher forming speed, better moisture resistance and better forming precision. Cibaltooisc-5210 is mainly used in environments requiring heat and moisture protection, such as underwater operation conditions. Somos series also has a new variety somos8120. The performance of this material is similar to that of polyethylene and polypropylene. It is especially suitable for making functional parts. It also has good moisture-proof and water-proof performance

Japan broke the Convention of using UV light source in SLA technology. With the cooperation of Japanese chemical pharmaceutical company in developing new photosensitive resin, denken engineering and autostrade took the lead in using semiconductor laser with wavelength of about 680nm as light source, which greatly reduced the price of SLA equipment. In particular, the edarts model of autostrade company adopts a restricted liquid level structure with a light source shining upward through a layer of glass from the lower part, which reduces the price of the equipment to 2.98 million yen. Xi'an Jiaotong University has launched LPS and CPS series SLA molding machines and corresponding photosensitive resins. CPS molding machine uses UV lamp as molding energy

3.2 laminated forming (LOM)

at present, helisys company, Huazhong University of science and technology, Tsinghua University, Kira company, Sparx company and Kinergy company are studying LOM Process. In addition to the original LPH, LPS and LPF paper products, helisys has also developed plastic and composite materials. HRP series molding machines and materials launched by Huazhong University of science and technology have high performance price ratio. Tsinghua University has launched SSM series molding machines and materials

3.3 selective laser sintering (SLS)

DTM company, EOS company, Beijing Longyuan company, Huazhong University of science and technology and Nanjing University of Aeronautics and Astronautics have studied SLS. DTM introduced sinterstation2000, 2500 and 2500plus models in 1992, 1996 and 1999. Among them, the modeling volume of the 2500plus model has increased by 10% compared with the past. At the same time, through the optimization of the heating system, the auxiliary time has been reduced and the molding speed has been improved. Beijing Longyuan company launched afs-300 molding machine. Huazhong University of science and technology has developed hrps-1 molding machine for casting medium sand molding, and hrps- Ⅲ molding machine for polymer powder molding. In terms of materials, DTM has several new products every year. Among them, duraformgf material has higher precision and smoother surface. The recently developed elastic polymer somos201 material has the characteristics of rubber, heat resistance and chemical corrosion resistance. It has been used to make anti leakage flexible parts such as serpentine tubes, gaskets and door seals in automobiles; Use rapidsteel2 O mold made of stainless steel powder, capable of producing 100000 injection molded parts; Rapidtool 2.0 has a shrinkage rate of only 0.2%. Its parts can achieve high precision and surface finish, and almost no subsequent polishing process is required. Dtmpolycarbon copper nylon mixed powder is mainly used to make small batch injection molds. EOS company has developed a new nylon powder material pa3200gf, which is similar to duraformgf of DTM. The precision and surface finish of the parts made of hydraulic sensor force measuring materials are good

3.4 fuse deposition forming (FDM)

STRATASYS and medmodeler mainly study FDM. STRATASYS developed the first fdm-1650 model in 1993, and successively launched fdm-2000, fdm-3000 and fdm-8000 models. What is striking is the FDM quantum model launched by STRATASYS in 1998, with a maximum modeling volume of 600mm × 500mm × 600mm。 Due to the use of the extrusion head maglev drive system, two extrusion heads can be controlled independently at the same time, so the modeling speed is 5 times that of the past. STRATASYS Co., Ltd. and medmodeler Co., Ltd. developed medmodeler models for some hospitals and medical research units in 1998, using ABS materials. In 1999, it launched Genisys XS, an improved model that can use polyester thermoplastic, with a modeling volume of 305mm × 203mm × 203mm。 Tsinghua University launched the MEM model

fuse wire materials are mainly ABS, artificial rubber, cast wax and polyester thermoplastic. In 1998, swinburm University of technology in Australia studied a metal plastic composite wire. In 1999, STRATASYS company developed water-soluble support materials, which effectively solved the problem of difficult or impossible removal of support materials in complex and small holes in the stage of comprehensive performance requirements (1970-1979)

3.5 others

in 1997, Z company launched z-402 model, which uses starch mixed with wax or epoxy resin as raw materials and sprays adhesive onto powder to manufacture parts. In 1998, prometal company launched rts-300 model, which takes steel, steel alloy, nickel alloy and titanium tantalum alloy powder as raw materials, and also adopts the technology of spraying binder on the powder, so that metal parts can be directly and rapidly produced

in 1999, 3D system developed a Thermojet solid object printer using thermoplastic, with higher forming speed

in 1998, New Jersey Institute of technology proposed a new rapid freeze forming (REP) technology, which uses pure water as the prototype material and brine with low freezing point as the supporting material to manufacture formed parts through selective deposition and rapid freezing. Since 1998, micro manufacturing technology has also been an active research direction of RP technology. A research group in the United States has used CAD technology to manufacture high-density parts with a diameter of only 100 microns; Another research group has studied a new micro manufacturing method, similar to the solid curing (SGC) technology, which is said to be capable of manufacturing

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