3D Printing Acronyms Explained: SLA

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The more 3D printing technology evolves, the more complicated it gets to try and keep up with the terminology.

ABS, PLA, FDM, SLS… the acronyms referring to the different technologies, materials and processes seem to be multiplying like flowers in spring.

In this series of blog posts, we’ll analyze all the different 3D printing related acronyms give you a quick, yet exhaustive explanation.

In this post, we’ll give you a primer to one of the main acronyms in the industry: SLA.

 

SLA: Stereolithography 

The term stereolithography refers to a 3D printing process. Stereolithography was actually the first additive manufacturing technology to be theorized and patented back in the 80s.

SLA 3D printers rely on two key components: a near-UV laser beam and a liquid photopolymer resin.

During the printing process the laser beam is focused on a thin layer resin and quickly draws a 2D section of the desired object (equivalently to any other 3D printing technology). The photosensitive resin reacts solidifying and thus forming a single 2D layer of the object thanks to UV light. Applying a new layer of resin on top and iterating the process for each section of the object results in the complete 3D printed object.

This video by Formlabs will help you better understand how the technology works:

 

Characteristics of an SLA 3D printer

 SLA 3D printer are complex machines and their applications can range from simple DIY objects to complex prototypes.

However, no matter how complex the machine is, the following sections will always be present on a SLA 3D printer:

– A tank filled with the liquid photopolymer: The liquid resin is usually a clear and liquid plastic.

– A perforated platform immersed in a tank: The platform is lowered into the tank and can move up and down according to the printing process.

– A high-powered, ultraviolet laser

– A computer interface, which manages both the platform and the laser movements

 

Pros and Cons of SLA 3D Printing

 

Pros 

– SLA is one of the most precise 3D printing techniques on the market.

– Prototypes can be created with extremely high quality, with finely detailed features (thin walls, sharp corners, etc…) and complex geometrical shapes. Layer thicknesses can be made as low as 25 μm, with minimum feature sizes between 50 and 250 μm.

– SLA provides the tightest dimensional tolerances of any rapid prototyping or additive manufacturing technology: +/- 0.005″ (0.127 mm) for the first inch, and an additional 0.002″ for each additional inch.

– Print surfaces are smooth.

– Build volumes can be as high as 50 x 50 x 60 cm³ without sacrificing precision.

 

Cons

– Printing tends to take a long time.

– Steep slopes and overhangs require support structures during the building process. Such parts may potentially collapse during printing or curing phases.

– Resins are comparatively fragile and therefore not suitable for functional prototypes or mechanical testing.

– SLA offers limited material and color choice, usually offering black, white, grey and clear material. Resins are oftentimes proprietary and therefore cannot be easily exchanged between printers from different brands.

– SLA printing costs are comparatively high (e.g. machine, materials, lab environment).

 

This quick introduction to SLA 3D printing is far from covering all the different, more technical aspects of the process, but it helps to understand a little bit better how the technology works, what you can do with an SLA printer and when it’s a good idea to use it.

Next up, in our series of 3D printing acronyms explained, we’ll talk about FDM.

Do you have any questions about SLA technology? Leave a comment below or join our forum and connect with thousands of  3D printing pros.

 

 

Via all3dp.com

Categories: Design & Process