Material Profile: Somos® Taurus™ Resin (Covestro / Stratasys) for Uniontech SLA 3D
Uniontech SLA Resin Technical Report Series
Compiled from Uniontech, Stratasys / Covestro official datasheets, SDS documents, and third-party technical reviews
Abstract—Somos® Taurus™ is a high-performance 355 nm SLA photopolymer co-developed by DSM Somos (now Covestro / Stratasys) with Toyota Motorsport GmbH for demanding automotive and aerospace prototyping. The charcoal-gray finish, isotropic mechanical properties, and ABS-like toughness — combined with the option of secondary thermal post-cure that raises HDT (0.45 MPa) from ≈ 62 °C to ≈ 91 °C — make it one of the few SLA resins suited to under-the-hood automotive testing and end-use service. Tensile strength 46.9 MPa, elongation 24%, Izod ≈ 37 J/m. Supported on Uniontech SLA platforms.
Index Terms—additive manufacturing, SLA, photopolymer, ABS-like, high heat, automotive, aerospace, charcoal gray, thermal post-cure.
I. MATERIAL IDENTIFICATION
This section establishes the canonical names and commercial designations under which the resin is supplied.
A. Designation
Trade name: Somos® Taurus™. Owner: Covestro (formerly DSM). Distributor: Stratasys; supported on Uniontech SLA platforms. Color: Charcoal gray.
B. Resin Family
High-toughness acrylate / urethane-acrylate photopolymer with thermally activated secondary cure capability; 355 nm UV laser cure + optional thermal post-cure.
C. Aliases and Alternative Designations
|
Alias |
Origin / Usage |
|
Somos Taurus |
Standard product designation |
|
DSM Taurus |
Original DSM (legacy) branding |
|
Covestro Taurus |
Current ownership branding |
II. COMPOSITION AND PHOTOPOLYMER CHEMISTRY
A. General Resin Family
Generic photo-polymerisation: monomers (multi-functional acrylates / urethane-acrylates) + photoinitiator + 355 nm UV laser → crosslinked thermoset network. Exact formulation is proprietary. Thermal post-cure activates additional crosslink mechanisms to elevate HDT.
Fig. 1. Photopolymer crosslinking schematic for the resin family.
Fig. 2. Industrial SLA print → wash → post-cure process flow.
B. Composition Breakdown
TABLE I COMPOSITIONAL BREAKDOWN OF SOMOS® TAURUS™ RESIN (TYPICAL / PER SUPPLIER DATASHEET)
|
Constituent |
Mass fraction |
Function |
|
Multi-functional acrylate + tough urethane-acrylate oligomers + thermal-cure crosslink modifiers |
≈ 70–85 wt% |
Form the backbone of the cured network |
|
Reactive diluents (low-viscosity acrylates) |
≈ 10–20 wt% |
Reduce viscosity for laser scanning; increase crosslink density |
|
Photoinitiator (laser-tuned, e.g., Irgacure / TPO blend) |
≈ 1–3 wt% |
Absorbs 355 nm UV; initiates radical polymerisation |
|
Pigments, stabilisers, additives |
≈ 1–3 wt% |
Color, UV blocker for shelf life, surface flow |
|
Total |
100 wt% |
— |
III. MECHANICAL PROPERTIES
Taurus is differentiated by its 'UV + thermal' two-stage cure: UV post-cure produces baseline mechanical properties; subsequent thermal cure substantially raises HDT and stiffness. Both cured states are tabulated below.
TABLE II MECHANICAL PROPERTIES OF SOMOS® TAURUS™ RESIN (POST-CURE, ISO 527 / ASTM D638)
|
Property |
Value |
Test method / source |
|
Density |
≈ 1.13 g/cm³ |
ASTM D792 |
|
Viscosity (uncured liquid) |
≈ 350 cP @ 30 °C |
Brookfield viscometer |
|
Surface hardness |
Shore D 83 |
ASTM D2240 |
|
Tensile strength at yield (UV cure) |
46.9 MPa (6.8 ksi) |
ASTM D638-14 |
|
Tensile strength at yield (UV + thermal cure) |
49.0 MPa (7.1 ksi); independently 51 MPa |
ASTM D638-14 |
|
Tensile modulus (UV cure) |
2,310 MPa (335 ksi) |
ASTM D638-14 |
|
Tensile modulus (UV + thermal cure) |
2,206 MPa (320 ksi) |
ASTM D638-14 |
|
Elongation at break (UV cure) |
24% |
ASTM D638-14 |
|
Elongation at break (UV + thermal cure) |
17% |
ASTM D638-14 |
|
Flexural modulus |
1,724–2,054 MPa (typical) |
ASTM D790 |
IV. RECOMMENDED PRINT PARAMETERS
Values below are the manufacturer-recommended starting points for compatible Uniontech industrial SLA printers (Lite, Pilot, RSPro series); specific machines may require ±10–20% adjustment based on laser power, build size, and ambient temperature.
TABLE III RECOMMENDED PRINT AND POST-PROCESS PARAMETERS FOR SOMOS® TAURUS™ RESIN
|
Parameter |
Value / range |
Notes |
|
UV wavelength |
355 nm (solid-state UV laser) |
Standard for industrial SLA |
|
Compatible printers |
Uniontech Lite450 / 600 / 800, Pilot250 / 450, RSPro600 / 800 / 1400 / 1800 / 2100 |
Industrial 355 nm laser SLA platforms |
|
Layer thickness |
0.05–0.15 mm (typical 0.10 mm) |
Industrial SLA layering range |
|
Laser scan speed |
≈ 5–15 m/s |
Galvanometer-driven; depends on printer model |
|
Recoating |
Wiper / vacuum recoating with auto liquid level control |
Maintains constant resin level for accuracy |
|
Wash medium |
TPM (tripropylene glycol monomethyl ether) or IPA |
Recommended for industrial cleanliness |
|
Post-cure |
UV oven, 30–90 min @ 405 nm broadband |
Required for full mechanical property development |
|
Optional thermal post-cure |
160–180 °C, 2–4 h (raises HDT from ≈ 62 °C to ≈ 91 °C) |
Improves HDT / strength on selected resins |
V. GLASS TRANSITION TEMPERATURE (TG)
Reported / typical Tg: ≈ 75–95 °C depending on cure schedule.
Two-stage cure: UV-only Tg ≈ 75 °C; UV + thermal Tg approaches 95 °C. Use thermal cure when service temperature exceeds 60 °C or when HDT > 80 °C is required.
VI. HEAT DEFLECTION TEMPERATURE (HDT)
HDT defines the temperature at which a 1.27 mm-thick standardised bar deflects 0.25 mm under the specified flexural load. Two test loads are reported per ASTM D648 / ISO 75.
TABLE IV HEAT DEFLECTION TEMPERATURE OF SOMOS® TAURUS™ RESIN
|
Test load |
HDT |
Test method / source |
|
0.45 MPa (UV cure) |
≈ 62 °C |
ASTM D648 (datasheet) |
|
0.45 MPa (UV + thermal cure) |
≈ 91 °C |
ASTM D648 (datasheet, Toyota Motorsport) |
VII. DISTINGUISHING CHARACTERISTICS AND STANDARDS
A. Industry-first 'UV + thermal' two-stage cure
Most SLA resins offer only UV post-cure. Taurus's thermal post-cure (typically 160–180 °C, 2–4 h) activates additional crosslink mechanisms, lifting HDT (0.45 MPa) from ≈ 62 °C to ≈ 91 °C — opening under-the-hood automotive and aerospace applications previously inaccessible to SLA.
B. Co-developed with Toyota Motorsport for racing service
DSM and Toyota Motorsport GmbH co-developed Taurus specifically for race-car functional prototypes that must survive elevated temperatures in test cycles. The motorsport pedigree is unusual among SLA materials and represents real-world validation under demanding conditions.
C. Charcoal gray aesthetic and isotropic properties
The deep charcoal-gray finish minimises painting effort for automotive interior prototypes. Mechanical properties are isotropic, allowing parts to be loaded in arbitrary directions without orientation-dependent failure modes.
D. Supports very large parts (up to 800×800 mm class)
Stratasys reports single-piece prints up to 31.5×31.5×23.6 inch (≈ 800×800×600 mm) on Neo800 and large Uniontech RSPro machines. Part bonding with industrial epoxies enables even larger assemblies.
VIII. REPRESENTATIVE APPLICATIONS
Somos® Taurus™ Resin is typically deployed in the following applications:
1) Customised end-use parts: Final-quality components in low-volume aerospace, motorsport, and bespoke automotive.
2) Tough functional prototypes: Repeated test-cycle prototypes for product development.
3) Under-the-hood automotive parts: Engine bay components requiring 80–90 °C HDT after thermal post-cure.
4) Functional testing for aerospace: Wind-tunnel models, ground-test fixtures requiring impact + heat resistance.
5) Low-volume electronic connectors: Heat-tolerant connector housings and brackets for mid-volume runs.
IX. REFERENCES
[1] Stratasys, “Somos® Taurus™ Data Sheet,” MDS_SL_Somos Taurus_0123a, 2023. Available: https://www.stratasys.com/contentassets/a8b909d90c3e41aea8211a64fbf4c8ee/mds_sl_somos-taurus_0123a-1.pdf
[2] Stratasys, “Somos® Taurus™ Material Page,” 2024. Available: https://www.stratasys.com/en/materials/materials-catalog/stereolithography-materials/somos-taurus/
[3] M. Petch, “DSM introduce high-resistance Somos Taurus SLA material in collaboration with Toyota,” 3D Printing Industry, 2017. Available: https://3dprintingindustry.com/news/dsm-introduce-high-resistance-somos-taurus-sla-material-collaboration-toyota-108565/
[4] Uniontech, “Uniontech Stereolithography Resin Catalogue (includes Somos Taurus),” 2024. Available: https://www.uniontech3d.com/stereolithography-resin/
[5] ASTM D638-14, “Standard Test Method for Tensile Properties of Plastics,” ASTM International.
[6] ASTM D2240-15, “Standard Test Method for Rubber Property — Durometer Hardness,” ASTM International.
[7] ASTM D648-18, “Standard Test Method for Deflection Temperature of Plastics Under Flexural Load,” ASTM International.
(Image Resource : Stratasys)