Stereolithography (SLA) is one of the most accurate and versatile 3D printing technologies available today. It uses a photopolymerisation process to create three-dimensional models from liquid resins. This technique has revolutionised several industries, offering innovative and efficient solutions for the design and production of high quality parts. In this article, we will explore in depth how SLA printing works, its materials, advantages and applications in different industries.
What is stereolithography 3D printing (SLA)?
Stereolithography (SLA) 3D printing is an additive manufacturing technique that uses a laser to cure and solidify a liquid resin layer by layer. This method is distinguished by its high resolution and ability to create fine details in printed parts. Over the years, SLA technology has evolved, allowing for faster print speeds and improved quality finishes. For more information about the different 3D printing technologies, you can consult our section of 3D printing.
Stereolithography is widely used in industries requiring high-precision prototyping and production of functional parts. Its ability to work with a variety of resins makes it a popular choice for applications ranging from jewellery to engineering, where great attention to detail is needed.
Brief history of stereolithography
Stereolithography was developed in 1986 by Chuck Hull, who patented the technique and founded 3D Systems, the first 3D printing company. Since its inception, SLA has been used primarily for rapid prototyping, enabling companies to reduce product development time and costs. In the 1990s, the technology began to expand into the industrial sector, where its ability to create accurate and complex models was valued.
With the advancement of technology and the reduction of costs, stereolithography has found its way into a variety of applications, from the manufacture of components in the automotive industry to the creation of customised medical devices. Today, SLA is recognised as one of the most versatile and effective technologies in 3D printing.
How does SLA 3D printing work?
SLA 3D printing uses an ultraviolet laser to cure and solidify a liquid resin in a series of thin layers. This process begins when a 3D model is sent to the printer, where the laser follows the contour of the first layer, solidifying the resin. After a layer is complete, the printing platform is lowered slightly, allowing a new layer of resin to be applied and repeating the process until the object is complete.
The light-curing process
The light-curing process is fundamental to SLA printing. It involves curing a liquid resin by exposure to ultraviolet light. This chemical reaction converts the resin into a solid, creating the layers of the 3D model. The precision of the laser allows for fine details and smooth finishes on the printed parts, which is ideal for applications requiring high quality. This process also allows for faster production compared to other 3D printing methods.
Key equipment and components of an SLA printer
SLA printers have several key components that enable their operation. The most critical element is the laser, which cures the resin. In addition, the printer includes a resin tank where the liquid material is placed, as well as a build platform that moves down as the layers are created. Temperature control and ventilation systems are also important to ensure a stable and high quality printing process. The combination of these elements enables SLA printers to deliver exceptional results in the creation of detailed models.
Design, printing and post-finishing in 3D SLA printing
Design in SLA 3D printing involves the use of 3D modelling software, where the objects to be printed are created. Once the model is ready, it is exported to the printer to start the printing process. After printing, it is common for parts to require post-finishing, which may include cleaning uncured resin, sanding and applying surface finishes. This process is essential to improve the quality of the final product and ensure that it meets the required specifications.
Materials used in SLA 3D printing
Stereolithography mainly uses liquid resins that are cured by ultraviolet light. These resins come in different formulations and properties, allowing them to be tailored to a variety of applications. From general purpose resins to those specialised for specific industries, the variety of materials available makes SLA printing extremely versatile.
General purpose resins
General purpose resins are ideal for prototyping and non-functional modelling. These resins offer good print quality and an acceptable surface finish, making them suitable for applications such as product visualisation and concept models. Their cost is generally lower compared to specialised resins, making them a popular choice for low-budget projects.
Specialty resins for engineering and manufacturing
Specialty resins are designed to meet the specific demands of engineering and manufacturing. These resins offer enhanced mechanical properties, heat and chemical resistance, making them suitable for applications in industrial environments. Their use is essential in the creation of functional parts and components that must meet high standards of quality and durability.
Resins for medical, dental and jewellery applications
Resins used in medical and dental applications are formulated to be biocompatible and safe for human contact. These resins are used to create dental models, surgical guides and customised medical devices. In jewellery, on the other hand, high-precision resins are used to produce intricate detail in jewellery, which is essential for the production of high quality jewellery.
Why choose SLA 3D printing?
SLA 3D printing stands out for its precision and reliability in part creation. Its ability to produce fine details and smooth finishes makes it an ideal choice for applications requiring high quality. In addition, the versatility in the materials used allows designers and engineers to select the resin that best suits their specific needs.
SLA not only offers a superior finish, but also provides greater design freedom. Designers can create complex geometries and parts that would be difficult or impossible to achieve with traditional manufacturing methods. This flexibility, combined with the precision of the technology, makes SLA printing an attractive choice for multiple industries.
Accuracy, reliability and fine detail
Stereolithography is known for its ability to print models with exceptional precision. This technology allows for fine details and complex geometries, which is critical in applications such as dentistry, where high-precision moulds and prosthetics are required. The reliability of the process also ensures that parts are reproduced with the same quality on every print, which is essential for maintaining production standards.
Surface finish and versatility of materials
The surface finish on SLA printing is remarkably smooth, reducing the need for post-finishing in many applications. This saves time and resources in the production process. In addition, the variety of materials available, ranging from flexible to rigid resins, allows designers to tailor their choices to the specific needs of the project, increasing the versatility of SLA 3D printing.
Isotropy and sealing in the manufacture of parts
SLA 3D printing is also characterised by its isotropy, which means that the mechanical properties of parts are consistent in all directions. This is critical for applications that require uniform strength in different orientations. In addition, the leak-tightness that can be achieved with SLA printing makes it possible to create parts that require a precise fit and the ability to contain liquids, which is essential in sectors such as automotive and medical.
SLA 3D printing applications in different sectors
SLA 3D printing has a wide range of applications in different sectors, thanks to its precision and versatility. From prototyping in product design to manufacturing final parts in specific industries, this technology has proven to be a valuable resource for many companies. Its ability to produce high quality parts with complex geometries makes it a preferred choice for modern manufacturers.
Product engineering and design
In the engineering and product design sector, SLA 3D printing enables designers to create functional prototypes with high precision. This fast and accurate production capability facilitates the development process, allowing testing and adjustments to be made at the earliest stages of design. As a result, companies can reduce time to market and improve the quality of their final products.
Automotive and aerospace manufacturing
The automotive and aerospace industry uses SLA 3D printing to produce components and replacement parts that require high precision and strength. The ability to create prototypes and custom parts quickly and efficiently has transformed the way vehicles and aircraft are developed and produced. In addition, weight reduction in printed parts can improve fuel efficiency and overall vehicle performance.
Use of SLA 3D printing in dentistry and medicine
SLA 3D printing has become an essential tool in dentistry and medicine. It is used to create customised dental models, splints and prostheses that perfectly fit patients' needs. The precision and smooth surface finish of the printed parts ensure that medical devices fit properly, improving comfort and efficiency in treatment.
Applications in jewellery and audiology
In the jewellery industry, SLA 3D printing enables the creation of intricate, customised designs that would be difficult to achieve using traditional methods. Printed parts offer a high level of detail and finish, which is essential for the production of high-end jewellery. In addition, in audiology, customised models are used for the manufacture of hearing aids, ensuring a comfortable and functional fit for the user.
