When it comes to pushing the boundaries of product design, SLA 3D printing materials are changing the game. Originally seen as the go-to tool for sleek prototypes and concept models, stereolithography resins have evolved dramatically. Thanks to advancements in photopolymer resin properties, what once was just a domain for visual mockups has now expanded into a full suite of materials suitable for rapid prototyping, industrial applications, and even biomedical components.
This shift isn’t just about aesthetics; it’s about performance. Material advancements have unlocked a broader spectrum of SLA resins, extending well beyond general-purpose use. R&D professionals and manufacturing engineers now have access to engineering SLA resins that are strong enough for mechanical testing, or durable enough for long-term wear. There are even biocompatible solutions and high-temp SLA resins for thermal applications, making SLA a viable tool far beyond what it was a decade ago. With this growing range of capabilities, stereolithography is no longer limited to “looks-like” parts; it’s becoming a valuable option for functional testing, fit checks, and even low-volume production.
To help make sense of the diverse materials available, we’ve broken down our SLA material portfolio into three key categories: General Purpose, Engineering, and Biocompatible. We’ve also translated trade names into real-world equivalents so you can match SLA options with familiar materials like polypropylene, ABS, or PC.
SLA resins have come a long way. What used to be utilized for mostly cosmetic purposes , ideal for visual modeling and conceptional prototyping, has evolved into a sophisticated range of performance-oriented materials.
With manufacturers demanding more, the new crop of precision SLA printing materials ensures exceptional mechanical properties, thermal stability and even regulatory compliance. Whether you’re a manufacturing engineer designing end-use parts or an R&D specialist conducting rigorous prototype testing, there’s a resin tailored to fit your needs.
When evaluating materials for a specific application, four key mechanical properties help define their performance profile: tensile strength, elongation, heat deflection temperature, and impact strength. Tensile strength measures how much force a material can withstand when being pulled before it breaks, which gives an indication of its overall strength. Elongation refers to how much a material can stretch before it breaks and helps describe how flexible or ductile it is. Heat deflection temperature indicates the temperature at which a material starts to deform under load, which shows how well it can handle elevated temperatures. Impact strength measures how much energy a material can absorb from sudden force without breaking. Taken together, these properties give a clear picture of how a material performs and make it easier to compare options based on the demands of your application.
General purpose SLA resins are well-rounded & can cover the greatest amount of use cases. Commonly used for visual protoyping and design validation, their strength is their reliability across a range of projects. These resins offer dimensional accuracy and good clarity, making them ideal perfect for initial iterations or straightforward geometries.
| Material | Tensile Strength (ksi) |
Tensile Modulus (ksi) |
Elongation (%) | HDT @ 264 psi (°F) |
Izod Impact |
Color |
|---|---|---|---|---|---|---|
| Watershed XC 11122 | 7.3 | 402 | 15.5 | 120 | 0.47 | Transparent |
| Watershed Black | 7.3 | 402 | 15.5 | 120 | 0.47 | Black |
| WaterClear Ultra 10122 | 8.1 | 418 | 7.5 | 109 | 0.47 | Transparent |
Watershed XC 11122 is a clear resin that mimics ABS and performs well for most visual prototypes. It balances strength, flexibility, and clarity, and has minimal moisture uptake, making it a go-to general purpose material for visual prototypes or designs that require some level of durability.
Watershed Black is mechanically identical to WaterShed XC 11122, but prints in an opaque black color. It’s ideal when aesthetics or light blocking matter and transparency aren’t needed. Like its sister WaterShed material, Watershed Black also imitates ABS with its properties, but has a semi glossy black color.
WaterClear Ultra 10122 sets the standard for transparency in SLA resins. This super high-clarity material mimics polycarbonate, and offers superior optical clarity with high strength and good impact. It is specifically formulated for light-transmitting applications such as optical lenses. It has lower elongation, making it more brittle than other SLA materials, but offers industry-leading clarity—comparable to glass—when post processed with sanding and a clearcoat.
For prototypes or parts requiring durability and resistance, choose engineering SLA resins built to take on a more functional role. These materials are specifically developed for strength, heat resistance, and mechanical stability , enabling engineers to create prototypes that perform in functional prototypes or testing.
Taurus is a tough, durable resin with high elongation and performs well for functional parts that require durability. Its ability to be heat treated or thermally cured (HT) to alter its properties makes it an excellent choice for demanding applications, like automotive interior parts, which require exposure to temperatures well above 100°F. It’s unique color does not change from post processing, and the opaque charcoal grey is great for highlighting fine features on a part, such as a logo.
Taurus mimics an ABS/PC blend material, depending on the finishing process. It has good impact strength or HDT that make it perfect for enclosures, housings, or other functional parts.
EvoLVe 128 offers the highest tensile strength and stiffness among the engineering resins. Its high tensile strength is excellent for structural prototypes where rigidity matters, or parts that require stability under mechanical loads. With excellent surface quality and dimensional ability, Evolve 128 has a higher stiffness and strength than ABS, but behaves more like a glass-filled material or stiff PC blend. Available in white, Evolve is an excellent substrate for parts that need to be painted for a finished product look.
9120 is the newest addition to our SLA resins lineup, expertly designed to bridge the gap between flexibility, toughness, and clarity. This unique flexible SLA material stands out with higher elongation than other engineering-grade options and nearly double the impact resistance of other general-purpose resins. This combination makes it ideal for applications requiring both resilience and visual quality, such as enclosures, snap fits, and functional models. 9120 prints with a clean, transparent look, offering both performance and a polished finish.
What sets 9120 apart is its exceptional flexibility. Its high elongation and excellent impact resistance closely mimic the properties of polypropylene (PP). Most resins have a modulus significantly higher than 200 ksi, which provides too much resistance for flexible parts. 9120 has a modulus at only 178 ksi, which allows it to flex and provide resilience for demanding applications.
9120 is a semi-transparent resin with a foggy, translucent white appearance. It allows light to pass through, making it suitable for applications where partial light transmission is needed. However, it does not offer the same visual clarity as WaterShed XC 11122 or WaterClear Ultra 10122, which are better suited for optically clear parts.
Biocompatible materials are built to meet specific certifications for medical or anatomical use. They’re often used for surgical models or training tools where compliance is key.
BioClear is engineered explicitly for medical applications, offering the clarity of WaterShed XC 11122 with added biocompatibility. It is capable of passing several ISO 10993 tests, making it ideal for medical device SLA materials like models used in planning surgical procedures, and passes the following key tests:
| Test | Standard | Result |
|---|---|---|
| Cytotoxicity Testing | ISO 10993-5:2009 | Somos Bioclear does not cause toxic effects on living cells. |
| Irritation Testing | ISO 10993-23:2021 | Somos Bioclear does not cause irritation or adverse skin reactions when it comes in contact with skin or mucous membranes. |
| Sensitization Testing | ISO 10993-10:2023 | Somos Bioclear does not cause allergic reactions over time. |
| Pyrogenicity Testing | ISO 10993-11:2018 Annex F, USP <151> | Somos Bioclear does not release substances that induce a fever reaction when introduced into the body. |
| Acute Systemic Toxicity | ISO 10993-11:2018 | Somos Bioclear does not cause systemic toxic effects when introduced. |
| Material Characterization | ISO 10993-18:2020 | Somos Bioclear does not leach harmful organic or inorganic substances (confirmed over 6 hours with 180 cm² of surface area contact). |
Understanding how SLA resins perform and align with common thermoplastics is critical in choosing the right material. Today’s offerings include options that mimic everything from polypropylene to polycarbonate and even glass-filled engineering plastics. This diversity allows manufacturers to streamline rapid prototyping workflows while ensuring that the performance meets the scope of industrial or medical needs.
Precision SLA materials are much more than just aesthetics. They empower you to produce resilient, lightweight, and regulated parts for SLA industrial applications and beyond. With the introduction of BioClear or 9120, this technology is poised to tackle challenges that conventional thermoplastics and other AM methods couldn’t previously address.
Whether it’s performance SLA materials for structural prototypes, ISO 10993 certified SLA materials for healthcare, or cutting-edge resins for precise SLA parts, knowing your options can dramatically transform your production timeline and meet real-world demands.
Still need some guidance on your stereolithography materials? Contact us. We’re here to help.
With over a decade of experience in additive manufacturing, Kevin drives the success of Stratasys Direct’s 3D printing services portfolio, shaping material strategies, optimizing product sales, and enhancing customer experience through e-commerce platforms. He has expertise in powder bed fusion technologies like SLS, SAF, and MJF, contributing to material development and process innovations in industries such as aerospace, automotive, and consumer goods. Kevin holds both a BS and an MSE in Mechanical Engineering from the University of Texas at Austin and is an active speaker at industry conferences like AMUG and RAPID + TCT.
