The charm of light and shadow 3D printing photopolymerization molding technology

Frederica 2023-04-07

rapid prototyping and additive manufacturing

3D printing (3DP), scientifically known as "additive manufacturing" (AM) or "rapid prototyping" (RPM), is a technology based on digital model files, under the control of a computer, through layer-by-layer printing to construct the actual product. The printing process mainly includes: 3D modeling, model slicing, and layer-by-layer printing.

3D printing information technology has been developed for more than 30 years since its birth, and currently China is in a state where multiple scientific and technological research lines can coexist. According to the differences in the form of consumables used by themselves and the working principles of molding, the current mainstream of society's 3D printing data technology to carry out the general content is divided into rapid prototyping and additive manufacturingcorporate extrusion melt molding and molding method principle differences, the current mainstream of China's 3D printing-related technology issues are roughly divided into three basic types of extrusion melt molding, granular material molding, light polymerization molding. Each product type students in accordance with the design molding process technology, and evolved a variety of ways kinds, which, melt lamination (FDM) belongs to our extrusion molding class, granular material molding and including the company directly affect the metal laser sintering (DMLS), electron beam melting (EBM), selective laser sintering (SLS), selective thermal sintering (SHS), selective laser melting molding ( SLM), and photopolymer molding system technologies include light curing molding (SLA), digital light processing (DLP), and polymer injection (PI).

3D printing main implementation technologies

According to the type of printing consumables, 3D printing technology can be divided into non-metal 3D printing technology and metal 3D printing technology, among which FDM, SLA, DLP, 3DP, etc. belong to non-metal 3D printing technology, SLm, DMLS, EBM, etc. belong to metal material 3D printing technology.

Introduction of photopolymerization 3D printing technology

Light polymerization 3D printing technology is the use of photosensitive resin materials in the light curing molding of 3D printing technology in general, mainly including three technical routes: one is developed by the United States 3D Systems and the first commercialization of stereolithography equipment technology (SLA); the second is the digital light processing (DLP) 3D printing technology, based on DLP projector technology by Germany envision TEC Research and development; the third is the Israeli Objet (merged with Stratasys in 2012) developed polymer jet rapid injection mouldingtechnology (PolyJet).

However, the use of different light sources, there are certain differences in product performance, application research scope and other aspects of development. Next, specifically from the basic principles of work, advantages and disadvantages, typical equipment, application issues and consumables and other several convenient analysis of the three information technology companies are discussed in detail.

Light-curing molding technology

Light-curing molding (SLA-RRB technology was invented in 1983 and patented in 1986. SLA, also known as "stereo light curing molding" or "laser light curing," was founded by Charles Hull in 1986 to promote the business of 3D systems. In 1988, the company produced and commercialized the world's first SLA 3D printer, the SLA 250, based on the principles of SLA molding technology, and over the years, 3D Systems has become the world's largest supplier of 3D printing equipment.

Charles Hull, the inventor of SLA and founder of 3D Systems

1、The working principle of SLA

SLA mainly through the use of liquid photosensitive resin in the UV laser beam under the irradiation of fast curing characteristics. Specific management of the basic principles we can achieve this to understand.

The first step is to fill the resin tank with liquid photosensitive resin, lift the table to the height of the cross-sectional thickness below the liquid surface, and scan the laser beam along the liquid surface under computer control according to the cross-sectional profile requirements to cure the resin in the scanned area, thus obtaining a resin sheet with a cross-sectional profile.

Step 2: The table is lifted down to a thickness of one layer, and the liquid resin is exposed again and scanned and cured again until the whole product is formed.

Step 3: Lift the table out of the liquid resin surface, remove the workpiece, and perform the related post-processing.

Schematic diagram of SLA working principle

In China at present, the application of research more several 3D printing information technology, rapid prototyping typesSLA because the enterprise has molding process to carry out a high degree of automation, the production of prototypes with high precision, good quality of surface work and students can effectively realize the characteristics of China's relatively fine size molding, so that it is more widely used.

The advantages and disadvantages of SLA technology is its earliest rapid prototyping manufacturing process and highly mature.

Prototypes are made directly from CAD digital models, fast processing speed, short product production cycle, no tools and molds are required.

High molding accuracy (about 0.1 mm) and good surface quality.

Disadvantages SLA system engineering cost is high, the use and maintenance of enterprise cost management is relatively too high.

The working environment is demanding, the consumables are liquid resin, which has odor and toxicity and needs to be sealed, while light protection is required in order to prevent polymerization in advance.

Most of the molded parts are resin with limited strength, stiffness and heat resistance, which is not conducive to long-term preservation.

The system is complex to operate and difficult to get started.

Post-processing is relatively cumbersome. Printed parts require data cleaning with industrial production alcohol and acetone, and research secondary curing.

Advantages and disadvantages of SLA technology

There are many institutions and companies in China that study SLA, including Huazhong University of Science and Technology, Zhuhai Xitong, and China Zhibao, as well as foreign 3D systems and template labs. 3D systems started earlier in the technology field. The models produced also represent the most advanced technology in the field.

Companies representing SLA technology: 3D Systems

3D Systems is the world's leading provider of 3D printing and printing solutions, and the creator of the 3D printing concept. 1986, Charles W. Hull, the inventor of SLA technology, established 3D Systems and worked on the commercialization of SLA technology. Up to now, the company's business has covered the entire 3D printing industry chain, including upstream materials, midstream equipment and downstream application services. The three businesses accounted for 24.30%, 43.35% and 32.35% of revenue in 2014, respectively.

3D Systems technical and economic strength development is strong, through students independent innovation and research and development, acquisition of companies merged, the company's products have set up a stereo light-curing molding (SLA) selective for laser sintering (SLS), color jet system printing (CJP), multi-jet printing (MJP) and other commercial production operations of 3D printers. At the same time, the company's Medical Modeling pioneered Virtual Web Surgical Information Technology (VSP), which has helped thousands of patients with its service quality at this world market-leading management level.

The history of 3D Systems is the history of the acquisition of the 3D printing chain

The history of 3 d Systems is the history of mergers and acquisitions throughout the 3 d printing industry. Since its inception, 3 d Systems has acquired dozens of companies across the 3 d printing chain, and the pace of mergers and acquisitions is accelerating, especially as interest in 3 d printing has grown in recent years. 2011 saw the acquisition of Quickpart, a custom parts manufacturer, and Company Z, a leader in multi-color inkjet 3 d printing. In August 2013, the company announced the acquisition of UK-based In August 2013, the company announced the acquisition of UK-based CRDM, which specializes in additive manufacturing and rapid prototyping services for the aerospace, motorsport and medical device industries, a move that helped the company establish a strong foothold in the UK market.

That same year, the company acquired Sugar Lab, which specializes in making desserts with 3D printing technology, Figulo, a leading provider of 3D printed ceramics technology, and Xerox's Product Design, Engineering and Chemistry Group in Wilsonville, Oregon. 2014 saw the culmination of the company's M&A, with the acquisition of Oklahoma-based sister companies, American Precision Prototyping and American Precision Machining, a medical modeling company, Laser Reproductions, a U.S. provider of advanced manufacturing product development and engineering services, Robtec, the largest 3D printing service provider in Latin America, Simbionix, a surgical device giant, Layer Wise, a Belgian provider of direct metal 3D printing and manufacturing services, and CADu002FCAM software To strengthen its business development in China, in 2015, 3D Systems acquired Wuxi Evey and its wholly owned subsidiary in China and created 3D Systems China.

The company's business revenue level growth rate development slowed down, net profit turned positive to negative, there is a corporate loss. 2014, the company can achieve revenue of $654 million, year-on-year growth of 27.3% respectively, the growth rate slowed down significantly, to achieve sales net profit of $11.64 million, a year-on-year decrease of 73.6%. 2015 first half, the company's revenue year-on-year actual growth rate for further economic slowdown to 10.7%, while net profit was -$26.88 million, a serious loss.

SLA-based 3D printing device: prox 950

The PROX 950 is a production-grade 3D printer manufactured by 3D Systems.The PROX 950 has a molding size of 1,500 x 750 x 550 mm and a maximum weight of 150 kg.The PROX 950 is faster than previous 3D printers, free from the limitations of injection molding or CNC design, and it uses new polymer ray technology that can print up to 10 times faster than other 3D printers. 10 times faster than other 3D printers. It takes only two days to produce a full-size dashboard.

The ProX 950 has high material utilization, with all unused material retained in the system, and a wide selection of materials to meet a range of part properties from the toughness of acrylonitrile butadiene styrene to the transparency of polycarbonate.

SLA has the advantages of fast processing speed, high molding accuracy, good surface proceeding quality, and mature technology development in China, and is widely used in aerospace, automotive, consumer goods, electrical appliance companies, and social medical fields in designing a concept, single-piece small batch precision casting, product information models, and mold structures.

3D printed Haier air conditioner

At present, light-curing molding (SLA) technology will develop in the direction of high-speed, energy-saving, environmental protection and miniaturization. With the continuous improvement of processing precision, SLA will be widely used in biological, medical, microelectronics and other fields.

Photopolymer printed items printed with photopolymer materials

The consumables for 3D printers based on stereolithography equipment technology (SLA) are generally liquid photosensitive resins, such as photosensitive epoxy resin, photosensitive vinyl ether, photosensitive acrylic resin, etc. A photosensitive resin is a resin that can be polymerized and cross-linked and cured by the action of a photosensitizer under UV light. It consists of a photosensitizer and a resin.

Digital Light Processing Information Technology (DLP)

DLP is a 3D printing and molding technology called digital light processing additive manufacturing (DLP). DLP has many similarities to SLA and also works by using the properties of liquid photosensitive polymers that cure under light. DLP technology uses a higher resolution digital light processor (DLP) to cure the liquid polymer, which is cured layer by layer, etc., until the final model is complete. DLP molding technology typically uses photosensitive resins as the printing material.

How DLP technology works

DLP and SLA are both photopolymerization. The major difference between the two is the light source; SLA uses a laser to focus on the liquid photopolymer, while DLP is a process of digitally processing the image signal and then projecting the light to cure the photopolymer.

When forming, SLA generally goes from point to line and then from line to surface, while DLP is formed layer by layer. Therefore, DLP can be formed faster than SLA. Due to the higher cost, 3D printers based on DLP technology are more expensive than FDM models and even higher than SLA models.

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