"Stereo lithography Apparatus" is abbreviated as SLA. With a laser focus to the light curing material surface specific wavelength and intensity, so from the point to line, from line to surface sequential solidification, to complete a level drawing operation, then the lifting platform in the vertical direction of a layer of the height, and then cured on another level. Such layers constitute a three-dimensional entity.

3D printing technology SLA

SLA History

Stereo Lithography Apparatus (SLA) is the earliest rapid prototyping technology which has been put forward and applied commercially.

In 1986, Dr. Charles W Hull of the United States, for the first time, proposed in his doctoral thesis the concept of rapid prototyping of three-dimensional objects by laser irradiation of liquid photosensitive resins, and applied for patents.

In 1988, the American 3D systems company commercialized the first modern rapid prototyping machine SLA250 according to the patent, and solidified the forming parts selectively with liquid resin, thus creating a new era of rapid prototyping technology.

After nearly 20 years of development, Sla has become the most mature and most widely used 3D printing typical technology. In the rapid prototyping machine installed around the world, the light curing molding system accounts for about 60%.

At present, there are SLA, SYStems, EOS, Z, Corporation, CMET, D-MEC, TeijinSeiki, 3D and MitsuiZonsen companies.

American 3D Systems company's SLA technology accounts for the largest proportion in the international market.

Materials for SLA molding technology

Internationally, there are mainly four series of SLA forming technology materials:
  • 1. Ciba company's CibatoolSL series;
  • 2. Dupont company's SOMOS series;
  • 3. Zeneca's Stereocol series;
  • 4. RPC's RPCure series.

Advantages of SLA

1. Stereolithography process is the earliest rapid prototyping process, high maturity, time tested.
2. The prototype is made directly from the CAD digital model, with fast processing speed, short product cycle and no cutting tools and dies.
3. It is possible to process prototypes and moulds that are difficult to shape with complicated structural shapes or traditional methods.
4. Make the CAD digital model intuitive and reduce the cost of bug fixes.
5. Provide the sample for the experiment, and then verify and check the result of the computer simulation.
6. Can be on-line operation, remote control, conducive to production automation.

Disadvantages of SLA

1. SLA system is expensive and expensive to use and maintain.
2. SLA system is to operate liquid precision equipment, demanding working environment.
3. Molding parts are mostly resin, strength, stiffness, heat resistance is limited, is not conducive to long-term preservation.
4. The pretreatment software and driver software are heavy in calculation and highly related to the processing effect.
5. Software systems are complex and difficult to access.

Applications of stereolithography


The development trend of SLA stereolithography is high speed, energy saving, environmental protection and miniaturization. The improved machining accuracy makes it possible to do much in biology, medicine, microelectronics and other fields.

In several kinds of rapid prototyping process currently used in light curing because of the forming process of high degree of automation, prototyping, good surface quality, high precision and can realize the shape characteristics such as fine, which has been the most widely used. In the conceptual design of AC, single and small batch product model, precision casting, rapid tooling and product oriented mould etc. are widely used in aerospace, automotive, electronics, consumer goods and medical industries.

Research progress of stereolithography Technology

Stereolithography technology has been playing an important role in the field of rapid manufacturing since the beginning of the world. It has become the focus of Engineering attention. The precision of stereolithography prototype and the cost of molding material have been the focus of research in this field.

Stereolithography Technology Research

The development of stereolithography technology has been mature today, and a variety of new molding processes are emerging. The following outlook on SLA technology from light curing, rapid prototyping manufacturing technology and biomedical two aspects.

1. Micro optical rapid prototyping manufacturing technology

At present, the traditional SLA equipment forming accuracy is + 0.1mm, which can meet the general needs of the project. However, in micro electronics and biological engineering, it is generally required that the parts have fine structures of micron or sub micron size, and the traditional SLA technology can not meet the needs of this field.

2. Biomedical field

Stereolithography technology provides a new method for not using traditional methods or difficult to produce human organ model, based on the CT image of the light curing technology is used in making complex surgery, prosthesis planning, oral and maxillofacial repair method. At present, a new interdisciplinary field in the frontier of life science research, tissue engineering, is one of the promising applications of stereolithography technology.