Current status and development trend of 3D printing technology
1.1 Characteristics of 3D printing technology
According to the characteristics of printing technology, 3D printing can be divided into:
①Stereolithography (SL). The laser scans and exposes the liquid photosensitive resin, the resin reacts and solidifies at the focused spot, and then the work platform reaches the next depth, keeping the liquid level at the focal plane, and gradually forming.
② Stereo lithographic printing technology. This technology uses a computer to control the laser to scan the surface of the liquid photosensitive resin point by point according to the information of each layered section of the part. The resin thin layer in the scanned area is cured by photopolymerization to form a thin layer, and the layer is cured. After that, the workbench moves down a distance of a layer thickness, and then a new layer of liquid resin is applied to the surface of the originally cured resin until a three-dimensional solid model is obtained. Mainly used for rapid prototyping of complex and high-precision fine workpieces.
③Three-dimensional light solid molding. After the photopolymer is sprayed, it is quickly cured by ultraviolet light according to the set program. It can be directly formed on the previous support layer, and finally the glue-mounted support material is clearly removed. It is suitable for making complex structures. The thickness of each layer can be accurate to 0.16μm. .
④Polyvinyl chloride (PVC) plastic hot stamping and laminating film. The cutting knife cuts layer by layer according to the cross-sectional data and piles it up, and finally pulls out the bottom layer of PVC material; the machine price and production cost are relatively low.
⑤Three-dimensional inkjet printing (3DP). The software divides the 3D computer-aided design (CAD) file into thin sections, and the sections are covered with powder. Coat the connecting body by inkjet method and print layer by layer to form a three-dimensional model.
⑥Digital Light Processing (DLP). Expose the surface of the photocurable acrylonitrile-butadiene-styrene copolymer (ABS) resin, and each layer is exposed for only a few seconds.
The working principle of 3D printing technology is to use computer modeling software (such as 3Dmax, etc.) to shape a virtual 3D three-dimensional model on a computer, and then convert the model file into a format that matches the 3D printer, and then the 3D printer divides the model as a whole according to the slicing program Many cross sections. Finally, the 3D printer completes the printing work by stacking the cross-sections into a 3D model.
The combination of 3D printing technology and computer building model technology has greatly accelerated the development of information manufacturing technology in the direction of network customization and digitalization, and has gradually become an indispensable part of my country's national economy. The printing technology of existing materials such as composite materials and metal materials is an important direction for the development of 3D printing, and it is also the main work form of customized products in many other manufacturing fields.
1.2 Advantages of 3D printing technology
3D printing technology avoids the cutting procedures of traditional manufacturing, does not need to be manufactured through molds, and the processing speed is relatively fast. The production cycle is relatively short. More importantly, 3D printing has great advantages when manufacturing small and complex objects. Advantage. Through the integrated printing technology, no secondary processing is required, and mass production and remote control are realized through online operation with a computer.
The most representative 3D printing technology is the fused deposition forming technology. Its working principle is to feed the hot-melt filament material into the nozzle through a wire feeding device, and under the control of computer software, the nozzle is heated to extrude the softened material. Start to move along the contour of the object until the filling and solidification of the semi-fluid material is completed, forming a three-dimensional printed product. For example, for three-dimensional printing of plastic products, the plastic is melted by heating the nozzle of the three-dimensional printer, and the plastic is rapidly cooled after extrusion, and is bonded and covered with surrounding materials. At this stage, Fused Deposition Molding Technology (FDM) can print metal, paraffin, ABS, polylactic acid (PLA), artificial rubber, etc., and produce 3D models, mechanical parts, daily necessities, etc., which are widely used in construction and automobiles. , Aerospace and medical fields. Compared with traditional mechanical processing and production, FDM technology has the advantages of low cost, wide range of materials, high utilization rate of raw materials, and low pollution.
2.1 Research status
Up to now, many kinds of manufacturing technologies have been produced based on the principles of 3D printing manufacturing methods, and many materials have been separated according to actual conditions. Commonly used materials for 3D printing include environmentally friendly materials such as PLA, stainless steel, titanium alloys, aluminum materials, gypsum materials, rubber materials, and durable nylon materials. The main types of technologies to achieve 3D printing include photopolymerization molding technology, granular material molding technology, extrusion molding technology, wire molding technology, lamination molding technology and powder layer nozzle technology 3D printing molding technology.
Take the construction industry as an example. From a design perspective: building a house does not require a complicated design process. Each professional designer completes his own design in a 3D model. Perhaps one day, everyone can download the desired building directly from the Internet. Model. For architectural modeling, surface modeling that is difficult to achieve in traditional buildings becomes easier in 3D printing, which is definitely good news for architects who pursue free modeling. There must be new structural design methods. For example, using finite element analysis, the existing structural design specifications and related technical standards may no longer be suitable for printing buildings, and industry specifications suitable for the application of 3D printing in buildings need to be developed. The new construction process requires new acceptance standards. And should develop new building inspection technology at the same time.
2.2 Exploration of materials
In terms of materials, the use of ceramics and clay has begun to be explored. In order to meet the needs of 3D printed buildings, many special materials may appear in the future, such as fiber materials, composite materials, chemical materials and smart materials. Material performance requirements will continue to be improved, material science research is developing in a microscopic direction, and new materials are more in line with building material standards. Take concrete as an example. First of all, the raw materials of concrete will become more extensive. For example, the cementitious material can use special cement, resin, magnesium cementing material, etc.; the quality requirements of coarse and fine aggregates will be higher to meet the needs of 3D printing. Concrete must have better fluidity, and be able to quickly condense in the air to be self-supporting. Admixtures may undergo fundamental changes, and their roles and mechanisms in specific systems are also completely different. Secondly, in the aspect ratio design, new theories may be needed to support, the performance of concrete has undergone tremendous changes, and the hardening and shrinkage properties have undergone fundamental changes.
There are also many main materials in the 3D printing industry, such as engineering plastics, photosensitive resins, rubber materials, and metal materials. Among them, engineering plastics are currently the most widely used type of 3D printing materials. Commonly used are ABS, PC-based materials, PLA, nylon-based materials, etc. Engineering plastics refer to industrial plastics used as industrial parts or housing materials. Plastic with excellent impact resistance, heat resistance, hardness and aging resistance. In addition, rubber materials and metal materials also play an unlimited role in cycling, medical and metal manufacturing industries with their respective advantages.
3.1 Application of 3D printing technology in manual manufacturing
The 3D printing technology is the most widely used in the manufacturing industry. From 3D printed ships, cars, 3D printed robots, and printed furniture, to small 3D printed screws and nuts, industrial parts, and mobile phone cases, all of these can be stacked by 3D printing. In 2014, HodLipson, a creative robotics laboratory at Cornell University in the United States, manufactured components such as microprocessors, batteries, and robot connectors, and was able to fully assemble lightweight robots.
3D printing molds also have certain advantages in controlling the manufacturing cost of precision parts. For some parts with smaller sizes and more complex shapes, 3D printing can make full use of materials and reasonably control the cost of parts manufacturing. It will have a positive impact on companies optimizing the manufacturing process of precision parts and improving corporate profits. In addition to the above aspects, 3D printing molds are also outstanding in improving the performance of precision parts products and realizing personalized manufacturing of precision parts products.
For some parts with smaller sizes and more complex shapes, the use of 3D printing can make full use of materials and reasonably control the cost of parts manufacturing. This will have a positive impact on companies optimizing the manufacturing process of precision parts and improving corporate profits. In addition to the above aspects, 3D printing molds are also outstanding in improving the performance of precision parts products and realizing personalized manufacturing of precision parts products. Companies can use 3D printing to optimize the manufacturing tools of precision parts, so that the corresponding tools can be designed with more ergonomics to improve their operating comfort and practicability, such as precision parts molds. By optimizing the design of manufacturing tools such as molds, the scrap rate of precision parts will be further reduced.
3.2 Application of 3D printing technology in the medical field
3D printing technology can be used to quickly and accurately create models of human organs. With the help of the organ model, the doctor can diagnose the patient's condition. At the same time, the human organ model can help doctors fully conduct preoperative discussions and find the best surgical treatment plan, thereby effectively shortening the operation time and reducing the risk of surgery. Due to the ease of use of medical models, the market in developed countries is rapidly expanding. In addition to medical models, 3D printing can also be used to manufacture highly effective drugs. Due to the high similarity of the size and shape of the drug, and the easy transplantation of the molding process, the application prospect is broad. American scientists have successfully used 3D printing rapid prototyping technology to produce controlled-release tablets for oral administration.
3D printing can also print artificial bones, using decomposable engineering materials as printer materials, and printing artificial bones with active factors and loose porosity through a 3D printer. And after implanting artificial bones into the body, after a period of decomposition, the calcified substances can be completely absorbed by the living body and form new bones. These have been fully verified in animal experiments [5]. A girl in England put on a 3D palm, a migrant worker put on a skull, and even the Australian company CSIRO can tailor titanium breasts and ribs for patients to create a 3D chest cavity. The American biotechnology company Organovo once used cell 3D printing technology to print the cell tissues needed by the liver in the cell culture base. After being cultured in a vessel, it can grow into a normal-shaped liver and transplant it into the human body.
3.3 Application of 3D printing technology in home consumption and entertainment
Most of the initial 3D printers have a single function and are mainly used in engineering construction and medical science. Due to the high price and large size, their application in the field of household consumption has been seriously affected. But with the emergence of desktop 3D printers for home and personal applications, the sales of 3D printers in the home consumer market are heating up day by day. As the price of home 3D printers continues to drop, the functions of printers have become more diversified, and the scope of application of 3D printers in the home consumer sector will rapidly expand. For example, in the food industry, in 2012, scientists at the University of Pennsylvania used 3D printer technology to print artificial meat in the laboratory. People can actually grow fresh meat tissue on the carbohydrate growth frame. The meat is very similar. Recent research results show that 3D printing technology has broad application prospects in the field of food production and manufacturing, although 3D printing food technology is still in the preliminary experimental stage.
In addition, some daily gadgets in the family, such as flower pots, pen holders, storage boxes, etc., can be designed according to their own wishes for the shape and size of the model, and then modeled on the computer and manufactured by 3D printing technology Out of the entity, add a different joy to life. If you have children at home, you can also use 3D printing to make toys for them, which not only cultivates the children's ability to use their hands and brains, but also saves the cost of buying toys.
4. Conclusion
3D printing technology has the characteristics of precise structure, good integrity and low cost. It has produced a series of products with good economic value and has begun to be widely used in many fields such as machinery manufacturing, construction, medicine and aerospace. In modern society, all walks of life have always insisted on the service principle and purpose that the customer is God. Therefore, 3D printing needs to make 3D printing products according to the diverse needs of different customers, and provide customers with works of the best appearance. Not only can it greatly reduce the production cost of the product and the risk of market competition, it also improves the consumption and living standards of many ordinary users to a certain extent.
Although the proportion of 3D printing technology in the global manufacturing industry is negligible, the development and application of 3D printing technology is also affected by various factors. However, with continuous research and technological progress, the application field of 3D printing will With continuous expansion, printing materials will become more diversified, and the functions of printing equipment will be more complete, and will soon have a profound impact on traditional production methods, leading a new wave of revolution in the global manufacturing industry.
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