Material Profile: Somos® Element™ Investment-Casting 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® Element™ is an antimony-free 355 nm SLA photopolymer engineered specifically for investment casting patterns — particularly demanding alloys (titanium, super-alloys) where antimony residue poisons the metal. Element delivers strong green strength for safe pattern handling, dimensional stability during storage, and burnout cleanness with trace ash residue (lightweight and easily removed) leaving a perfectly clean ceramic mould void. Distributed by Stratasys (Covestro Additive Manufacturing), supported on Uniontech SLA platforms.
Index Terms—additive manufacturing, SLA, photopolymer, investment casting, lost-wax, antimony-free, low ash, jewelry, aerospace casting.
I. MATERIAL IDENTIFICATION
This section establishes the canonical names and commercial designations under which the resin is supplied.
A. Designation
Trade name: Somos® Element™. Owner: Covestro Additive Manufacturing (formerly DSM). Distributor: Stratasys; supported on Uniontech SLA platforms. Color: Light green / clear-tinted.
B. Resin Family
Antimony-free acrylate photopolymer engineered for clean lost-wax burnout; 355 nm UV laser cure.
C. Aliases and Alternative Designations
|
Alias |
Origin / Usage |
|
Somos Element |
Standard product designation |
|
DSM Somos Element |
Original DSM (legacy) branding |
|
Covestro Element |
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. Antimony-free; designed for clean thermal burnout in investment casting cycle.
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® ELEMENT™ RESIN (TYPICAL / PER SUPPLIER DATASHEET)
|
Constituent |
Mass fraction |
Function |
|
Acrylate / urethane-acrylate matrix (antimony-free) |
≈ 70–85 wt% |
Photopolymer network optimised for clean burnout |
|
Reactive diluents and burnout-modifier additives |
≈ 10–20 wt% |
Lower viscosity for laser scanning; aids ash-residue cleanliness |
|
Photoinitiator |
≈ 1–3 wt% |
Absorbs 355 nm UV |
|
Stabilisers, light pigment |
≈ 1–3 wt% |
Light green tint, shelf life |
|
Total |
100 wt% |
— |
III. MECHANICAL PROPERTIES
Investment-casting pattern resins do not have meaningful end-use mechanical service — the pattern is consumed in the burnout cycle. Properties below are 'green' (handling) values from the Somos® Element datasheet.
TABLE II MECHANICAL PROPERTIES OF SOMOS® ELEMENT™ RESIN (POST-CURE, ISO 527 / ASTM D638)
|
Property |
Value |
Test method / source |
|
Density |
≈ 1.14 g/cm³ |
ASTM D792 (datasheet) |
|
Viscosity (uncured liquid) |
Low (designed for laser SLA scanning) |
Brookfield viscometer |
|
Tensile strength |
Per datasheet (typically 40–55 MPa green) |
ASTM D638M |
|
Tensile modulus |
Per datasheet (typically 1,800–2,400 MPa) |
ASTM D638M |
|
Elongation at break |
Per datasheet (typically 4–10%) |
ASTM D638M |
|
Hardness |
Shore D 80–86 (typical green pattern) |
ASTM D2240 |
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® ELEMENT™ 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 30–60 min only; over-cure may impair burnout cleanness |
Required for full mechanical property development |
|
Optional thermal post-cure |
Not required (or per datasheet) |
Improves HDT / strength on selected resins |
V. GLASS TRANSITION TEMPERATURE (TG)
Reported / typical Tg: Not directly applicable (casting pattern; consumed in burnout).
Pattern is consumed in investment heating cycle (typical peak ≈ 720–760 °C). Tg is therefore not relevant for end-use service.
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® ELEMENT™ RESIN
|
Test load |
HDT |
Test method / source |
|
0.45 MPa |
Not applicable (pattern is consumed in burnout) |
— |
|
1.82 MPa |
Not applicable |
— |
VII. DISTINGUISHING CHARACTERISTICS AND STANDARDS
A. Antimony-free formulation — critical for sensitive alloys
Antimony residue from photopolymer burnout poisons titanium and super-alloy castings, causing surface defects and metallurgical issues. Element's antimony-free chemistry was specifically developed for these alloys, enabling SLA patterns to compete with traditional wax patterns in aerospace, defence, and high-end medical alloy castings.
B. Trace ash residue, lightweight and easily removed
Patterns burn out leaving only minimal ash residue, with what remains being lightweight (easily removed by airblast or water rinse). This translates directly to lower mould prep time, lower rework rates, and higher yield in production foundries.
C. Strong green strength + dimensional stability
Unlike high-wax castable resins (which tend to be brittle and dimensionally unstable in storage), Element patterns can be handled, transported, and stored without breakage or distortion before investment.
D. Suitable for high-end alloy castings
Validated for titanium, super-alloys (nickel-based), gold, silver, platinum, and steel investment casting. The single-resin / multi-alloy capability simplifies foundry inventory.
VIII. REPRESENTATIVE APPLICATIONS
Somos® Element™ Resin is typically deployed in the following applications:
1) Aerospace titanium and super-alloy castings: Where antimony contamination is unacceptable for metallurgical reasons.
2) Medical / dental implant master patterns: Pre-cast verification and direct-to-investment patterns.
3) Premium jewelry casting (gold / silver / platinum): Replaces wax patterns for fine-detail jewelry production.
4) Industrial precision castings: Pumps, valves, manifolds where lost-wax accuracy is required.
5) Concept verification masters: Cast a low-cost alloy version to verify form before precious / specialty alloy commitment.
IX. REFERENCES
[1] Stratasys, “Somos® Element™ Data Sheet,” SL_AM_Somos-Element_Leaflet_EN_A4_0123a, 2023. Available: https://tech-labs.com/sites/default/files/pdf/sl_am_somos-element_leaflet_en_a4_0123a-2.pdf
[2] Stratasys, “Somos® Element™ Material Page,” 2024. Available: https://support.stratasys.com/en/Materials/Stereolithography/Somos-Element
[3] Covestro, “Somos® Element™ Product Page,” 2024. Available: https://am.covestro.com/en_US/products/stereolithography/somos-element.html
[4] Uniontech, “Somos Element Distribution Page,” 2024. Available: https://uniontech3d.de/products/somos-element/
[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.
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