SLA 3D Printing: Meaning & How it Works

An SLA 3D printer
An SLA 3D printer

3D printing allows users to create solid objects using the instructions of a digital file. When using SLA in 3D printing, the object is made by hardening liquid resin with laser. This offers a number of benefits, making SLA 3D printers some of the most popular on the market. For users who are new to SLA 3D printing, this guide will provide a detailed look at what it is and how it works.

SLA in 3D Printing

What does SLA stand for in 3D printing? SLA is an acronym for stereolithography. In simple terms, stereolithography is the process of creating three-dimensional objects by using a laser to draw images on a photosensitive resin. As the laser beam hits the resin, it hardens and takes shape. This process is repeated layer by layer 3- until you have your object complete.

SLA 3D printing process is no new concept. In 1984, Charles Hull developed and filed a patent for the stereolithography apparatus (SLA). This was followed by the commercial release of the first SLA machine in 1987.

Since then, there have been many advances in SLA 3D printing technology, making it one of the most used 3D printing methods. Today, the use of SLA in 3D printing has led to the production of almost anything you can imagine, from prototypes and jewelry to dental products such as implants and crowns.

After the SLA 3D printing meaning and origin, let’s now turn our attention to how the technology works.

SLA 3D printer working
SLA 3D printer working

How Does SLA 3D Printing Work?

The process of SLA 3D printing starts with the creation of a digital 3D model of the object you wish to create. This can be done using any 3D modeling software. Once you have your 3D model, it needs to be saved in a format that can be read by the SLA machine.

  • As soon as your file is ready, it’s time to start printing. The first thing that needs to be done is to prepare the build platform. This is usually done by cleaning it, among other things.
  • The next step is to load the resin into the SLA machine. The type of SLA 3D printing resin you use will depend on what material you want your final object to be made from.
  • Once the build platform is prepared and the resin is loaded, the SLA machine will start the printing process.
  • The laser will draw the object one layer at a time, curing the resin as it goes. As each layer is cured, the build platform will lower/move up slightly so that a new layer of resin can be cured on top.
  • After the printing is finished, the object will need to be removed from the build platform and any support material will need to be removed. The object can then be cleaned and post-processed as needed.
  A spool of SLA 3D printer resin
A spool of SLA 3D printer resin

SLA 3D Printing Materials

SLA 3D printing materials are typically resins (liquid plastics) that are cured using a laser. These are mainly classified as either standard or engineering (advanced) resins.

Standard resins are the most common and are typically used for general purpose applications. Engineering resins are designed for specific applications and offer improved properties, such as higher strength or heat resistance. They include the following.

  • Flexible resin – these are meant to be flexible and offer improved impact resistance
  • Transparent resin – high transparency SLA 3D printing resins that are often used for prototypes or medical applications
  • High temperature resin – these can withstand higher temperatures and are often used for end-use parts that need to be heat resistant
  • Castable resin – a type of resin that is castable and used for making molds or investment casting patterns
  • Durable resin– low friction resins that you can use to make hard-wearing parts

In addition to the different types of 3D printing resin, there are also a variety of colorants that can be added to the resin to change the color of the final object. This can be useful for creating prototypes or for adding a personal touch to an object.

SLA 3D Printing Advantages

There are many advantages to using SLA in 3D printing, including the following.

  • SLA 3D printing produces high accuracy and detail
  • Objects printed with SLA 3D printing machine have a smooth surface finish
  • You can use SLA 3D printing to create very complex shapes
  • A wide variety of materials can be used with SLA 3D printing
  • SLA 3D printing is a relatively fast process
  • SLA 3D printed parts have good mechanical properties

There are also some disadvantages to using SLA 3D printing, including the following.

  • SLA 3D printing can be a more expensive process than other 3D printing technologies
  • Resin materials can be toxic and require ventilation when used
  • Some SLA 3D printed parts can be sensitive to light over time
SLA 3D printing examples
SLA 3D printing examples

SLA 3D Printing Applications

The use of SLA in 3D printing is well suited for applications that require high accuracy, detail, and a smooth surface finish. This includes applications such as medical implants and dental crowns.

SLA 3D printing also allows you to create complex shapes that would be difficult to produce with many other manufacturing or 3D printing methods. These may include shapes with thin walls or intricate internal features.

The SLA 3D printing process is also often used for prototyping applications, as it can quickly and easily produce prototypes with a high level of detail. This allows designers and engineers to test the form, fit, and function of a design before moving on to production.

SLA 3D printing can be used to produce small batches of parts for end-use applications. This can be useful for creating custom or one-off parts, such as medical devices or art objects.

Post processing SLA prints
Post processing SLA prints

FDM vs. SLA 3D Printing

Fused deposition modeling (FDM) and stereolithography (SLA) are two of the most popular 3D printing technologies. Both technologies have their own advantages and disadvantages. Here is a quick review of FDM vs. SLA 3D printing.

1. FDM 3D printing is typically less costly than SLA 3D printing, as it uses inexpensive printing materials. This makes it a better option for general applications.

2. FDM 3D printing is a slower process when compared to SLA technology. SLA 3D printer parts consist of laser light that takes a shorter time to map the layers to be printed.

3. With SLA 3D printing, resolution levels are higher, with more detailed finished parts. FDM 3D printed parts tend to be less accurate and have a rougher surface finish than SLA 3D printed parts.

3. SLA 3D printing is usually more accurate and produces parts with a smoother surface finish. Additionally, SLA 3D printing can be used with a wider variety of materials than FDM printing.

When choosing a 3D printing technology from the two, consider the specific applications for the parts that will be printed. For example, if accuracy and detail are important, SLA printing may be the better option.

However, if cost is a primary concern, FDM 3D printing may be the better option. Additionally, it is important to consider the materials that will be used, as not all materials are compatible with all 3D printing technologies.


The use (and continued development) of SLA in 3D printing has opened up a new world of possibilities for businesses and individuals alike. The accuracy and speed of the process, as well as the wide range of materials that can be used, make it a viable option for a variety of applications. However, the cost of SLA 3D printers and resins, as well as the need for post-processing, should be considered before making the decision to use this technology.

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