3D Printing Technology

1 3D Printing

1.1 3D Printing Technology

3D printing technology can be traced back to the invention of inkjet printer in 1976. In 1984, Charles Hull applied optical technology to the field of rapid prototyping, opening the curtain of 3D printing. Since the 1980s, 3D printing technology has attracted worldwide attention and began to enter people's vision and life. Nowadays, 3D printing technology has been well developed and applied in many aspects, such as manufacturing, medical, academic, aerospace and military fields.

According to the characteristics of printing technology, 3D printing can be divided:

① Stereolithography (SL). The laser scans and exposes the liquid photosensitive resin, the resin at the focus spot is cured by reaction, and then the working platform is reached to the next depth, keeping the liquid level at the focal plane, and gradually forming.

② stereolithographic 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 cross-section information of each layer of the part. The thin layer of resin in the scanned area produces a photopolymerization reaction and solidifies to form a thin layer. After the layer is cured, the workbench moves down a layer thick, and then a new layer of liquid resin is applied to the surface of the previously cured resin until a three-dimensional solid model is. It is mainly used for rapid prototyping of complex and high-precision fine workpieces.

③ Three-dimensional light fixing molding. After the photosensitive polymer is ejected, it is rapidly cured by ultraviolet light according to the set program, and can be directly formed on the previous support layer, and finally the adhesive support material is clearly removed, which is suitable for making complex structures, and the thickness of each layer can be accurate to 0.16 μm.

④ Polyvinyl chloride (PVC) plastic hot stamping lamination. The cutting knife cuts layer by layer according to the cross-sectional data and accumulates it, and finally removes the PVC material at the bottom layer; the machine price and production cost are relatively low.

⑤ 3D inkjet printing (3DP). The software divides the 3D computer aided design (CAD) file into thin section pieces, and the section is covered with powder. The connector is coated in an inkjet manner and printed layer by layer to form a three-dimensional model.

⑥ Digital Optical Processing (DLP). The surface of the photocurable acrylonitrile-butadiene-styrene copolymer (ABS) resin was exposed for only a few seconds per layer.

3D printing technology is to use computer modeling software (such as 3Dmax, etc.) to shape a virtual 3D stereo 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 into many cross sections according to the slicing program. Finally, the 3D printer completes the printing work by stacking the cross sections into 3D models.

3D printing technology and computer building model technology has greatly accelerated the development of information manufacturing technology to network customization and digitization, and has gradually become an indispensable part of my country's national economy. 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 form of work for customized products in many other manufacturing fields.

1.2 3D Printing Technology

3D printing technology avoids the cutting procedures of traditional manufacturing industry, does not need to be manufactured through molds, the processing speed is also fast, and the production cycle is relatively short. More importantly, 3D printing has great advantages in manufacturing small and complex objects. Through the integrated printing technology, no secondary processing is required, and mass production and remote control are realized through online operation with a computer.

3D printing technology is the fused deposition forming technology. Its working principle is to send the hot melt filament material into the nozzle through the wire feeding device. Under the control of computer software, the nozzle is heated and squeezed out of the softened material. Start to move along the contour of the object until the filling and solidification of the semi-flowing material is completed to form a three-dimensional printed product. For example, for the three-dimensional printing of plastic products, the plastic is melted by heating the nozzle of the three-dimensional printer, and the plastic is quickly cooled after extrusion, and is bonded and covered with the surrounding materials. At present, fused deposition forming technology (FDM) can print metals, paraffin wax, ABS, polylactic acid (PLA), artificial rubber, etc., and produce 3D models, mechanical parts, daily necessities, etc., which are widely used in construction, Automotive, aerospace and medical fields. Compared with traditional mechanical processing, FDM technology has the advantages of low cost, wide range of materials, high utilization rate of raw materials and low pollution.

2 Current status of 3D printing requirements

2.1

Up to now, many kinds of manufacturing technologies have been produced according to the principle of 3D printing manufacturing methods, and many materials have been separated according to the actual situation. Commonly used materials for 3D printing include environmental protection materials PLA, stainless steel, titanium alloy, aluminum material, gypsum material, rubber material, durable nylon material, etc. The main types of technologies to realize 3D printing are 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 the perspective of design: building a house does not require a complicated design process. Each professional designer completes his own design in a 3D model. Maybe one day, everyone can download the desired building directly from the Internet. model. For architectural modeling, surface modeling, which is difficult to achieve in traditional buildings, becomes simpler in 3D printing, which is definitely good news for architects who pursue free modeling. New methods of structural design must emerge. For example, using finite element analysis, the existing structural design specifications and related technical standards may no longer be applicable to printing buildings. It is necessary to develop industry specifications suitable for the application of 3D printing in buildings. The new construction process requires new acceptance standards. And new building inspection technologies should be developed at the same time.

2.2 Materials

have begun to explore the use of materials such as ceramics and clay. In order to meet the needs of 3D printing 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 will develop in a microscopic direction, and new materials will be 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, cementitious materials can use special cement, resin, magnesium cementitious materials, 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 for self-support. Admixtures may undergo fundamental changes, and their actions and mechanisms in specific systems are completely different. Secondly, in 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 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. Common materials include ABS, PC materials, PLA, nylon materials, etc. Engineering plastics refer to industrial plastics used as industrial parts or shell materials. It is a plastic with excellent strength, 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.

2.3 3D Printing on Social Life

3D printing building technology integrates digital modeling technology, electromechanical control technology, information technology, building technology, architectural design, materials science, chemistry and other disciplines, and integration requires coordinated development. 3D printing buildings are very suitable for emergency housing and poor groups. The printers developed in the future can really create houses suitable for people to live in. After suffering from natural disasters, construction machines can quickly print out houses and can automatically install various facilities. These facilities are superior to disaster relief tents and activities in terms of function and strength. Future 3D printing buildings can also meet the needs of customized customers, especially for buildings and structures with complex and irregular appearances. Relatively speaking, 3D printing has unique advantages.

3D printing can easily meet people's creative ideas and needs at a very low cost and faster production speed in the creation of individual handicrafts, and can provide people with more ideas and more powerful help on the road of artistic creation. In addition, in terms of education, 3D printing allows students to observe the production process of a thing from scratch from a more intuitive perspective, and stimulate children's creativity. 3D printing will lead the progress of the times and new social changes. The main technical force.

3 Application Trend of 3D Printing Technology

3.1 3D Printing Technology in Manual Manufacturing Industry

3D printing technology is most widely used in manufacturing industry. From 3D printing ships and cars, 3D printing robots and printing furniture, to small 3D printing screws and nuts, industrial parts and mobile phone cases, all of these can be stacked by 3D printing. In 2014, the Creative Robotics Laboratory of Cornell University in the United States HodLipson manufactured components such as microprocessors, batteries and robot connectors, and was able to fully assemble light robots [4].

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 manufacturing cost of parts. This will have a positive impact on enterprises to optimize the manufacturing process of precision parts and increase 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 small size and complex shape, 3D printing can make full use of materials and reasonably control the cost of parts manufacturing, which will have a positive impact on enterprises to optimize the manufacturing process of precision parts and improve their 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. Enterprises can use 3D printing to optimize the manufacturing tools of precision parts, so that the corresponding tools are designed with more consideration of ergonomics to improve their operating comfort and practicality, 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 3D Printing Technology in Medical Field

3D printing technology can be used to quickly and accurately create human organ models. With the help of organ models, doctors can diagnose the patient's condition. At the same time, the human organ model can help doctors fully discuss before surgery 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 expanding rapidly. In addition to medical models, high-efficiency drugs can also be manufactured using 3D printing. 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. Engineering materials that can be decomposed are used as printer materials, and artificial bones with active factors and loose and porous are printed by 3D printer. And after the artificial bone is implanted into the organism, after a period of decomposition, the calcified material can be completely absorbed by the living body and form new bones. These have been fully verified in animal experiments [5]. A woman's children's clothing in England has a 3D palm, a migrant worker has a skull, and even the Australian company CSIRO can tailor titanium sternum and ribs for patients to create a 3D chest cavity. American biotechnology company Organovo used cell 3D printing technology to print out the cell tissue required by the liver in the cell culture medium holder. After being cultured in a vessel, it can grow into a normal-shaped liver and transplant it to the human body.

3.3 3D Printing Technology in Home Consumption and Entertainment

, most of the 3D printers have single functions and are mainly used in engineering construction and medical science. Due to their high price and large size, their application in the field of household consumption has been seriously affected. However, with the emergence of desktop 3D printers for home and personal applications, the sales of 3D printers in the home consumer market are increasing day by day. With the continuous decline in the price of home 3D printers, the functions of printers have become more diversified, and the application range of 3D printers in the field of home consumption 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 growth frame of carbohydrates. The taste is very similar to real meat. 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 flowerpots, pen containers, 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 through 3D printing technology. Entities add a different pleasure to life. If there are children in the family, they can also use 3D printing to make toys for children, 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 accurate 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 adhered to the service principle and purpose of customer is God, so 3D printing needs to make 3D printing products according to the diverse needs of different customers, and provide customers with the best-looking works. This can not only greatly reduce the production cost of products and market competition risks, but also improve the consumption and living standards of many ordinary users to a certain extent.

the main factors that restrict the development and application of 3D printing technology are the particularity of 3D printing materials and the applicability of printing equipment. At present, the rapid prototyping materials available for 3D printing technology mainly include polymer materials, metal materials and inorganic non-metals. Although polymer materials have been widely used in commercial 3D printers, the application of other materials is still in the initial stage of exploration (for example, materials limited to specific plastics, resins and metals, and the accuracy can only reach the micron level), so the limited number of printing materials It largely limits the promotion of 3D printing technology. Fortunately, with the continuous development and progress of science and technology, more and more molding materials and material types with good comprehensive properties will appear in the future, which provide good support for the further development and promotion of 3D printing technology. On the other hand, with the continuous increase of available materials for 3D printing technology and the continuous improvement of the working ability of 3D printers, the types of solid models that can be printed by 3D printers will show an increasing trend, and the application field of 3D printing technology will also Continue to expand. The most important thing is that with the improvement of equipment and the continuous development of emerging processes, the dimensional accuracy and material performance of 3D printing products will be further improved, and the impact on the traditional mechanical manual manufacturing industry will gradually show. In the field of personal applications, facing the individual needs of different consumer groups, there will be a more compact, convenient, economical and practical model suitable for the office environment.

Although 3D printing technology accounts for a negligible proportion in the global manufacturing industry, the development and application of 3D printing technology are also affected by various factors. However, with continuous research and technological progress, 3D printing The application field will continue to expand, printing materials will be more diversified, the functions of printing equipment will be more perfect, and it will soon have a profound impact on traditional production methods, leading a new wave of revolution in global manufacturing.

The above articles are from the new materials industry, by Ma Xiaowei, etc. Please contact and delete if infringement.