Stereolithography (SLA) 3D Printing Guide: Everything You Need to Know

Stereolithography (SLA) has become a widely-employed additive manufacturing process. With its unique ability to produce isotropic, lightweight, and higher-accuracy products, several industries use it. In addition, this method supports a wide range of materials to deliver a smooth surface finish. On this note, this SLA printing guide will help you understand this process better.

Whether you are a beginner or an SLA 3D printing expert, our SLA guide covers all aspects that help you get started with ease. Once you understand how this 3D printing process works, it will become easier for you to decide how to use it. So, dive into this free tutorial of SLA additive manufacturing technique from Zeal 3D and explore this advancement.

What is Stereolithography (SLA) 3D Printing?

SLA is a popular 3d printing technology that works on the Vat Photopolymerization principle. This process makes the object selectively curing a polymer-based resin using a UV laser beam. Similar to other methods, SLA also follows a layer-by-layer approach to building parts. Common materials used in this method are photosensitive thermoset polymers that are in a liquid state.

Going a little back to history — it's among the earliest technologies, and the inventory patented this method in 1986. Back then, when manufacturers had to produce parts with a smooth surface finish, SLA was the most cost-effective way. As this manufacturing process produces lightweight components, it becomes an instant hit. This technology shares several characteristics with Direct Light Processing (DLP), a Vat Photopolymerization method.

SLA 3D Printing Workflow

Designing

First, you need to prepare a CAD file that you can produce using any software and export it in a 3D format like OBJ or STL. Every SLA matching comes with dedicated software to define slicing and printing settings. Once the slicing is done, the software sends printing instructions to the machine.

Printing

After the settings are done, the printing process can run simultaneously until the design is complete. Some printers also come with a cartridge system in which the material is refilled automatically by the machine.

Post-processing

Once the printing process is done, the engineer rinses the object in isopropyl alcohol (IPA) to ensure no uncured resin is present on the surface. After the parts are dried, some SLA materials need post-curing, which help the components to achieve excellent stability and strength. In the final stage, the engineer removes the supports from the part.

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Technical Working

The printing platform is kept in the liquid photopolymer tank at a one-layer height distance. Then, the UV laser cures and solidifies the resin. Next, the intense laser beam focuses on the predetermined path using a set of mirrors, known as galvos. Finally, the complete cross-sectional area of the 3d model is scanned to produce a solid part.

Once a layer is finished, the platform moves ahead, and the sweeper blade coats the surface again. This SLA process repeats itself until the part is ready. The piece then goes for post-processing work to achieve the desired customization.

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Characteristics of SLA

While working with SLA additive manufacturing, you need to know about the working and characteristics.

Printer Parameters

The manufacturers prefix the majority of the printer's parameters, and you cannot change them. The only parameters that you can change are part orientation and height. The layer height remains between 25 to 1000 microns. In most cases, the layer height of 100 microns is ideal.

Support Structure

SLA 3D printing always needs support structures to perform operations. The supports are made up of the same Stereolithography materials as the part, and you need to remove them manually. The position and orientation of the part define the amount of support.

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In top-down SLA printers, the overhang angle is around 30°, and the part is easy to position in any orientation as they are printed flat. On the other hand, the bottom-up process is more complicated as the overhands and bridges minimize the cross-sectional area.

Curling

Curling is a serious issue relating to the accuracy of parts produced via SLA. Curling is similar to warping in FDM. Curling is the most complicated problem of this additive manufacturing technique that minimizes the part's accuracy. However, it's identical to the FDM's warping problem, which beginners need to consider. In this glitch, the resin shrinks as it comes in contact with the printer's light source.

Layer Adhesion

As the parts have isotropic mechanical characteristics, a single UV laser cannot cure the liquid. Thus, to get the best mechanical properties, you must post-cure the parts by keeping them in a cure box under intense UV rays. It is because it helps in improving the adhesion between the layers.

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Popular SLA Materials

You will find a variety of ideal materials for both SLA rapid prototyping and main product manufacturing. Below are some common materials that you will easily find to achieve any surface finish:

Standard resin
Clear resin
Castable resin
High-temperature resin
Durable resin
Dental resin

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Why Pick SLA 3D Printing?

SLA offers several manufacturing benefits compared to other additive and traditional processes. Some key advantages that make SLA better are:

Higher Isotropy

Compared to FDM or other processes, SLA parts offer higher isotropy. Thus, it helps engineers achieve the same mechanical properties across all X, Y, Z dimensions.

Watertightness

Watertightness is important where fluid flow or the air needs to be controlled. With SLA, engineers can quickly solve the air and fluid challenges using the watertightness of the printers.

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Greater Accuracy

Be it automotive, dental, or consumer products manufacturing; companies pick SLA technology as it offers higher accuracy regardless of the product quantity.

Wide Range of Material Applications

SLA resins bring in a wide range of customization that makes it easier for manufacturers to meet all design and function requirements. From flexible to a rigid and soft texture, SLA materials support a variety of operations.

Smooth Surface Finish

SLA derives a smooth surface finish compared to several other additive processes. As a result, it's a competitive advantage for companies where they need to produce flawless designs.

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SLA Applications

Rapid prototyping of complex designs
Creating superior fit dental implants
Manufacturing custom tools and molds
For producing custom jigs and fixtures
Preparing wind tunnel models and more

Wrapping Up

We hope you get a quick overview of SLA 3d printing with this free eBook. If you plan to opt for additive manufacturing for your business, SLA is an ideal method as it offers several benefits.

Industries and Applications

The following industries are the most ardent users of AM technologies in their businesses.

Automotive

Lightweight aerodynamics parts are desirable in the automobile industry. This contributes to making cars more energy efficient. 3D printing in the automotive industry is used both for rapid prototyping services as well as for some end parts creation.

Manufacturing

The precision and accuracy of 3D print processes are helping the manufacturing industry reduce material wastage, save time, money, and efforts.

R&D

Rapid prototyping has become a crucial component used in R&D departments of leading businesses. It helps save time and money for the manufacturers.

Medical and Healthcare

This is one of the most promising sectors for applications of 3D printing. Some of the applications include prototyping for product development to creating actual patient solutions, such as dental crowns, prosthetics, implants, human tissues, and organs, as well as 3D printed surgical instruments.

Architecture

3D architectural models enable businesses to showcase accurate details of projects. Architects also have greater design flexibility when they use 3D CAD models.

Jewellery

Lightweight aerodynamics parts are desirable in the automobile industry. This contributes to making cars more energy efficient. 3D printing in the automotive industry is used both for rapid prototyping services as well as for some end parts creation.

Aerospace/Defence/Navy

This industry was one of the earliest adopters of additive manufacturing. Rapid prototyping has become a critical component in the development of replacement and end parts in this industry.

Stereolithography (SLA) 3D Printing Guide: Everything You Need to Know

What is Stereolithography (SLA) 3D Printing?