The Earliest Commercialized 3D Printing Technology

Stereolithography, also known as Stereolithography Apparatus (SLA), refers to a molding method that uses ultraviolet light to irradiate liquid photosensitive resin for polymerization reaction, so as to cure layer by layer and generate a three-dimensional entity. Workpieces prepared by SLA have high dimensional accuracy, which is the earliest commercialized 3D printing technology.

As the earliest 3D printing technology, SLA technology is also the most mature 3D printing technology, which is widely used in the industry. At present, large industrial light-curing 3D printers are mainly based on SLA technology.

SLA technology mainly uses photosensitive resin as raw material and utilizes the characteristic that liquid photosensitive resin will be rapidly cured under ultraviolet irradiation. Photosensitive resin is generally liquid, and it will immediately cause a polymerization reaction under the irradiation of ultraviolet light with a certain wavelength to complete the curing. SLA focuses ultraviolet light with a specific wavelength and intensity on the surface of the photosensitive resin, so that it solidifies point-by-point and line-by-line, ultimately forming a complete cross-sectional layer. After completing the drawing operation of one layer, the lifting table moves a layer height in the vertical direction, and then another layer is cured. Layers are stacked to form a three-dimensional object, and the formation of the pattern of each layer is controlled by the movement of the laser beam. In theory, the laser beam can move in a large space. Therefore, SLA technology can print large-sized objects.

Advantages of SLA

1.SLA is the earliest rapid prototyping process with high maturity.

2.The prototype is directly made from the digital model, with fast processing speed, short product production cycle, and eliminating the need for cutting tools and molds.

3.It has high forming accuracy, can print models with rich details, and has good surface quality.

Disadvantages of SLA

1.The cost of SLA system is high, and the use and maintenance costs are relatively high.

2.The working environment requirements are relatively harsh. The consumable is liquid resin, which emits odors, requires containment within a sealed system, and must be protected from light exposure to prevent premature polymerization.

3.Most of the printed parts are resin-based, so the strength and heat resistance of the printed products are limited, which is not conducive to long-term preservation.

4.The post-treatment is relatively tedious. The printed workpieces need to be cleaned with ethanol or a specific cleaning solution and undergo post-curing.

However, with the continuous progress of technology, SLA 3D printing technology is anticipated to find broader applications.