Light and shadow glamour 3D printing photopolymerization molding technology

【Chinese Packaging Network News】 Photopolymerization 3D printing technology is a generic term for the use of photosensitive resin materials in the curing of light 3D printing technology, which mainly includes three technical routes: First, developed by the United States 3D Systems and the earliest Commercialization of photocurable molding technology (SLA); the second is the development of DLP 3D printing technology based on digital light processing (DLP) projector technology based on the German envision TEC company; its third is the Israeli Objet company (2012 with Stratasys merged) developed polymer jet technology (PolyJet).

Photopolymerization class 3D printing technology classification

Technology Type Light Sources Representing Businesses

Light Curing (SLA) UV Laser Beams 3D Systems

Digital Light Processing (DLP) Digital Light Envision TEC

Polymer Jet (PolyJet) Light Source UV (UV) Stratasys

Light and shadow glamour 3D printing photopolymerization molding technology

SLA technical inventor and founder of 3D System, Charles Hull

However, different light sources are used, and there are differences in product performance, application range, and the like. Next, the three technologies are discussed in detail in terms of working principles, advantages and disadvantages, typical equipment, application fields, and consumables.

Photocurable molding technology (SLA)

Photocuring molding technology (SLA) was invented by Charles Hull in 1983 and patented in 1986. It is the earliest commercially available 3D printing technology. SLA is also known as "stereolithography" or "laser curing." In 1986, Charles Hull established 3D System Co., Ltd. to vigorously promote related business development. In 1988, the company produced SLA 250, the world's first SLA 3D printer, based on the principle of SLA molding technology, and commercialized it, after many years of development. , 3D System has become the world's largest provider of 3D printing equipment.

1. How Does SLA Work?

SLA mainly utilizes the characteristics of liquid photosensitive resin fast curing under the irradiation of ultraviolet laser beam. The specific working principle can be understood as follows:

The first step is to fill the resin tank with a liquid photosensitive resin. The worktable can be raised and lowered at a height of a section under the liquid surface. The focused laser beam is scanned along the liquid surface under the control of the computer according to the requirements of the section profile. The scanned area resin is cured to obtain the cross-sectional contoured resin sheet.

The second step: lift the workbench down one layer thick, the liquid resin is exposed to light again, scan and cure again, and repeat until the entire product is formed.

The third step: lifting platform lifts up the liquid resin surface, removes the workpiece, carries on the related post-processing.

SLA working principle diagram

Among several 3D printing technologies currently used, SLA has been widely used due to its high degree of automation in molding process, high production prototype accuracy, good surface quality, and ability to achieve relatively fine dimensional forming.

Advantages and disadvantages of SLA technology Advantages are the earliest rapid prototyping manufacturing processes with high maturity.

Prototyped directly from the CAD digital model, the processing speed is fast, the product production cycle is short, no cutting tools and molds are needed.

High precision (about 0.1mm) and good surface quality.

Disadvantages SLA systems are costly and the use and maintenance costs are relatively high.

The working environment is demanding, consumables are liquid resins, have odor and toxicity, and need to be sealed. At the same time, in order to prevent premature polymerization, light protection is required.

Most of the molded parts are resins, and their strength, rigidity and heat resistance are limited, which is not conducive to long-term preservation.

The software system is complicated to operate and difficult to get started.

Post-processing is relatively cumbersome. Printed parts need to be cleaned with industrial alcohol and acetone and re-cured.

The advantages and disadvantages of SLA technology

There are many institutions and companies that research SLA in China. There are Huazhong University of Science and Technology, Xitong in Zhuhai, Zhilei, etc. In China, there are 3D Systems, Formlabs, and so on. Among them, 3D Systems started earlier in the technology field, and the models produced also represent The most advanced technology in the field.

Light and shadow glamour 3D printing photopolymerization molding technology

Representatives of SLA Technologies: 3D Systems

3D Systems is the world's leading provider of 3D printing and printing solutions and the creator of 3D printing concepts. In 1986, SLA technology inventor Charles W. Hull was founded to establish 3D Systems and is committed to commercializing SLA technology. Since its development, 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 the total revenue in 2014 respectively.

3D Systems has strong technical strength. Through independent research and development, mergers and acquisitions, etc., the company has successively established 3D printers such as stereolithography (SLA) selective laser sintering (SLS), color jet printing (CJP), and multi-jet printing (MJP). The commercialization of the operation. At the same time, the company's Medical Modeling pioneered Virtual Surgical Technology (VSP), whose services have reached world-leading levels and have helped thousands of patients.

The history of 3D Systems is a history of mergers and acquisitions in the 3D printing industry chain

The history of 3D Systems is a history of M&A of the entire 3D printing industry chain. Since its establishment, the company has successively acquired dozens of companies around the entire 3D printing industry chain, especially with the increasing attention to 3D printing in recent years. The pace of mergers and acquisitions continues to accelerate. In 2011, the company acquired Quickparts, a custom component manufacturer, and Z Corporation, a leader in multicolor inkjet 3D printing. In August 2013, the company announced the acquisition of UK-based CRDM, which specializes in rapid prototyping and rapid tooling services for the aerospace, motor sports and medical equipment industries. This measure has helped the company to stabilize the UK market.

In the same year, the company has purchased Sugarlab, a leading supplier of 3D printed ceramic technology, and Sugar Engineering, a product design, engineering, and chemical group based in Xeroxville, Oregon. In 2014, the company's mergers and acquisitions reached a peak, with the acquisition of Oklahoma-based sister companies American Precision Prototyping and American Precision Machining, Medical Modeling, US advanced manufacturing product development and engineering services company Laser Reproductions, and Latin America’s largest 3D printing service provider Robtec. , emulated surgical equipment giant Simbionix, Belgium's direct metal 3D printing and manufacturing service provider Layer Wise, and CAD/CAM software vendor Cimatron. In order to strengthen business development in China, 3D Systems acquired Wuxi Yiwei and its wholly-owned subsidiary in China in 2015 and created 3D Systems China.

The company's income growth slowed down, net profit turned negative, and there was a loss. In 2014, the company achieved revenue of 654 million U.S. dollars, a year-on-year increase of 27.3%, a slower growth rate, and a net profit of 11.64 million U.S. dollars, a year-on-year decrease of 73.6%. In the first half of 2015, the company's revenue growth slowed further to 10.7% year-on-year, while net profit was -26.84 million US dollars.

SLA type 3D printing equipment: ProX 950

The ProX 950 is a production-grade 3D printer produced by 3D Systems. The ProX 950 has a molding size ofmm and a maximum weight of 150kg. Compared to previous 3D printers, the ProX 950 is faster and it is free from injection molding or CNC design. Restricted, using the new PloyRay technology, its printing speed can reach 10 times that of other 3D printers. It takes only 2 days to make a full-size dashboard.

ProX 950 has a high material utilization rate. All unused materials are kept in the system. The material selection is extensive, and it can satisfy a series of parts properties from the toughness of acrylonitrile butadiene styrene to the transparency of polycarbonates.

SLA has the advantages of high processing speed, high forming precision, good surface quality, and mature technology. It is widely used in aerospace, automotive, consumer goods, electrical appliances, etc. in terms of design concepts, single-piece precision casting, product models, and molds. Medical and other fields.

3D Printed Haier Air Conditioner

At present, SLA technology will develop in the direction of high speed, energy conservation, environmental protection and miniaturization. With the continuous improvement of processing accuracy, SLA will be more widely used in biology, medicine, and microelectronics. .

The 3D printer consumables based on photo-curable molding (SLA) are generally liquid photosensitive resins such as photosensitive epoxy resins, photosensitive vinyl ethers, photosensitive acrylic resins, and the like. Photosensitive resin is a kind of resin that can be polymerized and cross-linked and cured by the action of a photosensitizer under the irradiation of ultraviolet rays and consists of a photosensitizer and a resin.