Stereolithography (SLA) 3D printing is a popular additive manufacturing technique used to create accurate, high-quality parts from liquid resin. It works by using a UV laser to solidify specific areas of the resin, layer by layer, eventually forming a solid object.

SLA 3D printed parts are known for their fine detail, smooth surfaces, and high accuracy. A wide range of SLA resin options are available, suited to a variety of applications including cosmetic models, functional prototypes, manufacturing tools and end-use parts.

In this article, we’ll take a closer look at the range of materials used in stereolithography 3D printing and compare six different resins offered by LPE.


What Materials Are Used in Stereolithography?

Stereolithography, or SLA, is an additive manufacturing technique that uses a computer-controlled laser to selectively cure liquid resin layer-by-layer. When exposed to the UV light, the molecules within the resin undergo a chemical reaction called photopolymerisation, causing them to bond together and solidify. The process repeats to build the next layer, continuing until the entire three-dimensional object is formed.

SLA 3D printed parts boast high resolution and accuracy, fine details, and a smooth surface finish that is difficult to achieve with other 3D printing methods. There are many types of resins available for stereolithography, making the technology adaptable to a variety of industries and applications.


Properties of SLA Printing Materials

Various 3D printing SLA resins have been developed over the years, designed to mimic traditional manufacturing materials such as nylon, ceramic and ABS. Each resin boasts its own unique physical, visual and mechanical properties. Some SLA material properties include:

  • Strength and toughness: for impact-resistant parts used in demanding industries such as motorsport.
  • High surface quality: ideal for parts that require a smooth finish, such as aesthetic prototypes and display models.
  • Highdetail resolution: necessary for intricately detailed designs and complex geometries.
  • Flexibility: ideal for products that require bending or twisting without breaking.
  • Heat Resistance: useful for parts that need to withstand higher temperatures, such as automotive components or electrical housings.
  • Transparency: useful in applications such as lenses and flow visualisation models.
  • Dimensional stability: many SLA materials can maintain their shape and dimensions even under stress, wear and tear, ideal for ensuring product longevity.
  • Biocompatibility: some stereolithography materials are biocompatible and sterilisable, meaning they can be used for medical devices and surgical tools.

This diversity allows manufacturers to craft the perfect SLA 3D print to suit their specific requirements, whether for rapid prototyping, tooling or end-use parts.


Comparing Different SLA Resin Types

At LPE, we offer a wide variety of materials for our SLA 3D printing service. Below, we’ll take a look at six photosensitive resins, compare their properties and discuss their key applications.


1.      Xtreme: Excellent All-Round Resin

Xtreme is a versatile, multi-application grey material designed to mimic the properties of ABS and polypropylene. It is a tough, durable and heat-resistant SLA resin that also boasts excellent moisture resistance. Xtreme is a great choice for:

  • Fit, form, and function testing
  • Snap-fit assemblies
  • Tough enclosures
  • Electronic components
  • Master patterns for RTV silicone mouldings

Xtreme can also be used to replace CNC machining of ABS, polypropylene and polycarbonate products.


2.      Watershed: Transparent and Biocompatible

Watershed is an ABS-like clear SLA resin that meets USP Class VI and ISO 10993 standards for biocompatible applications. Almost completely transparent, it is a strong contender for the best SLA resin for prototypes requiring visual clarity. It also benefits from high tensile strength and ductility. Some example uses include:

  • Medical models
  • Packaging
  • Water flow analysis
  • Durable concept models
  • Lenses

As a biocompatible and sterilisable resin, Watershed is often utilised in the medical and food industries. It is also suitable for wind tunnel testing in motorsports and aerospace.


3.      PerFORM: Strong, Stiff Ceramic Composite

PerFORM is a ceramic SLA resin – a tough, off-white composite material infused with ceramic particles for added durability. It produces strong, stiff 3D printed parts that also boast high thermal resistance and superior sidewall quality. PerFORM is a good candidate for:

  • Rapid tooling e.g. custom moulds
  • Wind tunnel testing
  • High-temperature testing
  • Electrical casings
  • Automotive housings

PerFORM resin is also ideal for high-resolution printing, producing extremely detailed and complex parts with a smooth surface.


4.      Taurus: Durable and Heat-Resistant

Taurus is a durable, high-temperature SLA resin designed to simulate charcoal ABS. It offers impressive strength and durability with a thermoplastic-like feel. It also benefits from excellent isotropy and a high-quality finish, making it a top choice for complex designs and demanding applications. For example:

  • High-impact casings
  • Functional prototypes
  • Load-bearing components
  • Housings

Industries that benefit from the high-temperature resistance and durability of Taurus resin include automotive, aerospace, and industrial design.


5.      Si25: Tough and Flexible

Si25 is a tough, flexible SLA resin with the aesthetics of moulded polypropylene. Accurate, durable and white in colour, it’s an excellent choice for functional components and assemblies. Some example applications include:

  • Functional prototypes
  • Master patterns for RTV silicone mouldings
  • Automotive and electronic components
  • Concept models
  • Snap-fit assemblies

Si25 resin is used widely in industries such as automotive, consumer electronics, and toy manufacturing, among others.


6.      SL7820: Excellent Dimensional Stability

SL7820 resin simulates CNC-machined black ABS parts, offering excellent strength and dimensional stability even under humid conditions. Its potential applications include:

  • Automotive parts
  • Consumer goods
  • Packaging
  • Electronics
  • Toys
  • Housings

Yielding rigid and tough black components without the need for painting, SL7820 is an ideal alternative to injection moulding for short production runs and functional end-use parts.


Why Choose LPE for SLA 3D Printing?

LPE is the longest-established 3D printing service in the UK and Ireland, with over 30 years of experience across a variety of industry sectors. If you are looking for fast, accurate SLA 3D printing, our experts have the technical expertise necessary to ensure excellent results every time.

We are ISO9001 and ISO13485 quality assured and offer a wide range of SLA materials with excellent material properties. . Our team of model makers also offer a complete in-house post-processing service including testing, assembly, inserts and custom finishing. We pride ourselves on our fast lead times of 3-5 days, with free delivery to the UK and Ireland.

Contact LPE to learn more and discuss your requirements with our friendly team. Alternatively, request a quote for your next project today.




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