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SLA resin materials offer exceptional precision, surface finish and feature resolution for industrial 3D printing. In this guide, we explore the different categories of SLA resins, compare their mechanical and thermal properties, and offer guidance on selecting the right material for functional prototypes, tooling and end-use parts.
Stereolithography (SLA) is a vat photopolymerisation process that uses a laser to selectively cure liquid resin layer by layer. This enables highly accurate, isotropic parts with fine details and smooth surface quality. SLA is widely used in product design, engineering validation, dental and medical applications, and high-detail prototyping. The precision of the process makes it particularly valuable when tolerances are tight or when surface aesthetics are critical. Designers often choose SLA when form and feel need to closely mimic injection moulded plastics during early development.
Unlike FDM or SLS, SLA uses thermoset materials rather than thermoplastics. Once cured, resins cannot be remelted or reshaped, which gives them excellent dimensional stability and creep resistance but limits recyclability. This makes SLA particularly suited to parts that must retain their shape under mechanical stress or thermal exposure, such as jigs, fixtures or end-use components in controlled environments.
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Standard SLA resins are designed to provide a balance of ease-of-use, dimensional accuracy and fine detail. They are best suited for early-stage prototyping (compare SLA vs FDM processes for prototypes) where visual form, texture and assembly testing are key.. These materials cure quickly and can be printed at relatively high speeds, making them ideal for fast-turnaround models. Their colour range supports visual differentiation, and transparent variants allow inspection of internal features. While not as tough as engineering-grade alternatives, standard resins provide enough rigidity for mock-ups and non-functional components.
Use case: Design teams creating form models for consumer products or packaging mock-ups.
Engineering resins include multiple sub-types, each optimised to replicate a different family of thermoplastics. Tough resins, for example, are engineered to absorb energy without cracking, suitable for snap-fit assemblies or functional enclosures. Rigid resins contain glass or ceramic fillers that significantly boost stiffness and thermal stability, often used in mounts or structural components. High Temp resins offer exceptional resistance to heat deformation and are ideal for short-run tooling or components exposed to elevated temperatures. These resins typically require longer post-curing and stricter handling procedures to achieve optimal properties.
Use case: Jigs and fixtures, low-volume production parts, housings and brackets.
Flexible and elastic resins are elastomeric materials used to simulate rubber or silicone components. Elastic resins generally offer lower Shore hardness values, making them stretchable and suitable for soft-touch buttons or medical models. Flexible resins, on the other hand, tend to be more robust, with higher tensile properties and greater shape memory. These resins allow for design verification of overmoulded parts, ergonomic grips or cushioning elements. However, they also have lower tear strength compared to injection moulded elastomers, so they are best used in non-load-bearing applications.
Use case: Seals, gaskets, overmoulds and wearables.
Biocompatible SLA resins are manufactured under stringent quality control and often validated to ISO 13485 standards. These materials can be used in temporary or permanent skin and mucosal contact, depending on their formulation. Dental resins range from rigid model resins used in orthodontics to flexible splint and aligner resins. Surgical guide resins are engineered to remain stable under sterilisation protocols such as autoclaving, and they feature high optical clarity for visibility during procedures. Certification and traceability are key with medical resins, and users should always consult technical documentation to confirm suitability.
Use case: Dental models, aligner moulds, surgical planning tools.
Casting resins are designed for investment casting workflows, commonly used in industries like jewellery, dentistry and aerospace. These resins typically contain wax fillers or proprietary chemistries that ensure a clean burnout with minimal ash residue. This property allows foundries to use printed patterns without modifying traditional casting techniques. Surface finish is paramount, so these resins must be printed at high resolution and carefully post-processed to avoid layer lines or imperfections that would transfer to the final metal part.
Use case: Jewellery, dental frameworks, aerospace and automotive cast parts.
| Application Type | Recommended Resin | Key Property Focus | Post-Processing Notes |
|---|---|---|---|
| Visual Prototypes | Standard Resin | Surface finish and detail | Easy support removal and painting |
| Functional Assemblies | Tough Resin | Impact strength, ductility | Needs full UV cure for toughness |
| Structural Brackets | Rigid Resin | High stiffness, low creep | Brittle – avoid in snap fits |
| High-Temp Tooling | High Temp Resin | Heat resistance >200°C | Requires extended post-curing |
| Rubber-like Components | Flexible/Elastic Resin | Flexibility and compression | May require lubrication for use |
| Biocompatible Parts | Medical/Dental Resins | ISO 10993/FDA certified | Must follow certified workflows |
| Metal Casting Patterns | Casting Resin | Clean burnout, no residue | Surface prep critical before cast |
| Resin Type | Key Property | Tensile Strength | HDT | Elongation | Typical Applications |
|---|---|---|---|---|---|
| Standard | Smooth finish | 30–50 MPa | 45–60°C | 6–10% | Prototypes, mock-ups |
| Tough | Impact resistance | 40–55 MPa | 45–60°C | 30–60% | Snap fits, functional enclosures |
| Rigid | High stiffness | 70–100 MPa | 70–90°C | <5% | Mounts, structural parts |
| High Temp | Thermal resistance | 50–70 MPa | 200°C+ | 2–4% | Moulds, heat-resistant tooling |
| Elastic/Flexible | Rubber-like flexibility | ~2–4 MPa | ~30°C | 100–160% | Seals, gaskets, soft components |
| Casting | Burnout for metal casting | N/A | N/A | N/A | Investment casting patterns |
A Tier 1 automotive supplier used SLA High Temp resin to produce short-run mould inserts for under-the-bonnet components. These inserts were integrated into a vacuum forming process used to prototype engine bay covers and airflow ducting. The SLA-printed tools were post-cured to enhance heat deflection and then mounted into a hybrid steel fixture to improve lifespan.
During testing, the inserts withstood repeated thermal cycles exceeding 220°C without visible deformation, confirming the resin’s suitability for low-volume thermoforming. This approach saved four weeks on traditional tooling lead times and reduced costs by over 60% compared to machined aluminium blocks. It also allowed for iterative design changes between cycles, which would have been unfeasible with CNC-machined tools.
Additionally, feedback from production technicians noted that the SLA tools enabled more precise edge definition on formed sheets due to their smoother surface, reducing post-trim time by 30%. This insight demonstrates how material choice impacts not just the printed part, but the entire prototyping and testing workflow.
Always start by assessing how much stress the part will encounter in service. SLA parts destined for functional testing or mechanical assembly must handle more than just light handling. For structural support brackets or housings that see clamping forces, rigid or tough resins offer the best balance of strength and resilience. Tough resins provide a degree of flexibility under stress, which prevents cracking under snap fits or bending. Rigid materials, while less forgiving, offer greater stiffness and long-term dimensional stability (detailed SLA accuracy and tolerances guide). If parts are too brittle, failure may occur during installation or real-world use, so verifying mechanical loads early is crucial.
The thermal demands of the application must guide material selection. Standard SLA resins typically begin to soften or warp around 50–60°C, which makes them unsuitable for parts exposed to warm enclosures, near engines, or under direct light. High Temp resins, on the other hand, are engineered to perform in sustained thermal environments and can maintain shape and strength at over 200°C. These are often used for mould inserts, electrical insulation components or ducting in high-heat zones. It’s also important to consider short-term vs continuous heat exposure, as even high-performance resins have thresholds for time and intensity. For example, a resin might tolerate a 220°C spike for a few seconds during vacuum forming, but would fail under constant exposure at the same temperature.
The visual and tactile quality of SLA prints is one of its key strengths, but resin type affects final appearance. Clear resins allow designers to inspect internal channels or simulate transparent enclosures but require multi-step polishing to achieve optical clarity. Grey or white resins are more forgiving for inspecting fine details and serve well in early-stage product design. For presentation models or customer demos, choosing a resin that accepts paints, coatings or dyes easily can dramatically improve the finished look. Resin pigmentation can also impact print accuracy slightly, so always calibrate supports and exposure settings accordingly. When appearance is critical such as in high-end packaging prototypes or medical device casings—these details matter.
Any application involving human contact, especially in medical, dental or wearable products, requires resins tested to strict international standards. ISO 10993 and USP Class VI are benchmarks for safety, covering cytotoxicity, irritation and sensitisation. Resins that meet these standards undergo extensive validation, often including batch traceability and clean-room production. Using uncertified resins in skin-contact applications introduces legal and health risks. Additionally, post-processing for biocompatible parts must follow strict protocols, including sterilisation and prevention of contamination. Users should ensure that every stage, from material storage to curing, is compliant with the intended regulatory framework. Deviating from these standards may invalidate a product’s compliance status or expose users to liability.
SLA prints require post-curing, which completes the polymerisation and ensures final mechanical properties. Other common post-processing steps include support removal, typically using manual tools or ultrasonic cleaners. UV curing follows, often using a chamber with 405 nm light for durations between 15 and 60 minutes. Sanding, polishing and coating further refine the part’s visual and functional performance. For instance, optical parts benefit from wet sanding and polishing, while end-use parts may require primers and industrial coatings for wear resistance.
Well-executed post-processing can improve part durability, appearance and tolerance.
Rigid and Tough resins offer the highest strength and stiffness among SLA materials. Rigid is best for dimensional stability, while Tough balances strength with ductility.
Yes, particularly with engineering resins. Tough, High Temp and Rigid resins are suitable for functional prototypes and low-volume production.
Only biocompatible resins that meet ISO 10993 or FDA regulations should be used for skin or mucosal contact. Avoid using standard resins in wearable applications.
Standard resins typically withstand 45–60°C. High Temp resins exceed 200°C after post-curing. Check manufacturer datasheets for exact values.
Yes. SLA parts can be sanded, primed and painted for aesthetic or functional coatings. Surface preparation improves adhesion and final appearance.
Choosing the right SLA resin depends on understanding your application’s mechanical, thermal and aesthetic requirements. Whether you’re producing a prototype, tooling insert or biocompatible medical guide, there is likely an SLA material engineered for the job. Reviewing datasheets, trialling small batches and consulting with your 3D printing partner can help ensure success.
Explore our full range of 3D Printing Services or browse our Technologies to find the ideal process for your part. Or dive deeper into SLA 3D printing applications for industrial use cases.
Have you used SLA resin in your industrial projects? Share your experience or ask a question below.
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