PP-Like · grade
PP-Like SLA355
Properties of the SLA355 condition, compared with the other PP-Like grades.
Vat resins for large-frame laser SLA machines (Somos/Accura PP-like class) when part size and accuracy dominate.
What is PP-Like SLA355?
PP-Like SLA355 is PP-Like in the SLA355 grade — vat resins for large-frame laser SLA machines (Somos/Accura PP-like class) when part size and accuracy dominate. PP-Like SLA355 has a yield strength of 30 MPa (4.35 ksi) and a tensile strength of 32 MPa (4.64 ksi) — weaker than 90% of polyurethane grades. Elongation at break is 55% and the elastic modulus is 1.2 GPa (0.174 Msi). PP-Like SLA355 has a density of 1.15 g/cm³ (0.0415 lb/in³), heavier than 63% of polyurethane grades. Its glass-transition temperature is 55°C (131 °F). STD is the default condition FabDigit quotes; SLA355 is available on request or by drawing note.
Limitations
- Limited service temperature — 50°C (122 °F), worse than 100% of polyurethane grades
- High embodied carbon — 6 kg CO₂/kg, worse than 96% of polyurethane grades
- Low strength — 30 MPa (4.35 ksi), worse than 90% of polyurethane grades
PP-Like SLA355 properties
Typical room-temperature values for PP-Like SLA355 — 8 properties are specific to this condition; the rest are grade-level values shared by every PP-Like grade. Each bar shows where the value sits among the polyurethane grades in FabDigit's library — further right is higher.
Physical5
PP-Like SLA355 has a density of 1.15 g/cm³ (0.0415 lb/in³), heavier than 63% of polyurethane grades. Its glass-transition temperature is 55°C (131 °F).
Mechanical17
PP-Like SLA355 has a yield strength of 30 MPa (4.35 ksi) and a tensile strength of 32 MPa (4.64 ksi) — weaker than 90% of polyurethane grades. Elongation at break is 55% and the elastic modulus is 1.2 GPa (0.174 Msi).
Thermal10
PP-Like SLA355 is rated for continuous service to 50°C (122 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 57% of polyurethane grades. Thermal expansion is 120 µm/m·K (66.7 µin/in·°F).
Electrical7
PP-Like SLA355 is an electrical insulator with a dielectric strength of 17 kV/mm (431.8 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 73% of polyurethane grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PP-Like SLA355 takes about 120 MJ of energy and emits 6 kg of CO₂ — more than 98% of polyurethane grades. Typical recycled content is 0%.
Manufacturability4
PP-Like SLA355's machinability is good (55/100, worse than 67% of polyurethane grades); weldability not recommended (5/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other PP-Like grades and fills
PP-Like is also supplied in 7 other conditions. The full side-by-side table is on the PP-Like overview.
- STDDefaultDefault choice for functional prototypes, snap-fits and enclosures on desktop LCD/DLP printers.36 MPa tensile
- HTChoose when parts see hot air, lamps or short thermal cycles above 60 °C; stiffer and less ductile.48 MPa tensile
- ClearUse for light pipes, fluidic mock-ups and see-through housings where PP-like toughness is still needed.38 MPa tensile
- SLA355Vat resins for large-frame laser SLA machines (Somos/Accura PP-like class) when part size and accuracy dominate.32 MPa tensile
- ToughPick when living hinges, repeated snap engagement or drop survival matter more than stiffness.30 MPa tensile
Working with PP-Like SLA355
Is PP-Like easy to machine?
Drills and mills cleanly with sharp, high-rake tools and light cuts; avoid heat build-up above ~50 °C which softens and smears the part.
Can PP-Like be welded?
Thermoset — cannot be heat welded; join with cyanoacrylate, epoxy or fresh resin cured under a 405 nm lamp.
Can PP-Like be formed, bent or molded?
Printed only by vat photopolymerization; keep exposure and layer settings tuned, then wash briefly in IPA and post-cure warm (50–60 °C) to reach rated toughness without over-embrittling.
What surface finishes work on PP-Like?
Sands and primes well; use filler primer plus 2K clear or paint, and always add a UV-blocking topcoat because bare parts yellow and embrittle in sunlight.
PP-Like chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| aliphatic urethane acrylate oligomerbackbone giving PP-like toughness | 35 – 60 | 48 |
| monofunctional acrylate monomer (IBOA/EOviscosity control, flexibility | 15 – 35 | 25 |
| difunctional acrylate crosslinker (HDDA/crosslink density / stiffness | 8 – 25 | 15 |
| photoinitiator (TPO / TPO-L / BAPO)405 nm or 355 nm sensitized | 1 – 4 | 2.5 |
| TiO2 pigment / opacifierwhite PP-look grades | 0 – 4 | 1.5 |
| additives (dispersant, defoamer, UV blocbalance to 100 % | balance | — |
PP-Like SLA355 — frequently asked
What is PP-Like SLA355 used for?
PP-Like SLA355 is typically used for snap-fit parts, hinged enclosures, living-hinge test parts, thin-wall containers and caps, cable clips and retainers and fit-and-function assembly checks. In short: semi-flexible; survives living hinges like molded PP.
What is the yield strength of PP-Like SLA355?
PP-Like SLA355 has a typical yield strength of 30 MPa (4.35 ksi) and a tensile strength of 32 MPa (4.64 ksi) — weaker than 90% of polyurethane grades. Strength varies by condition: see the 8 listed tempers.
Is PP-Like SLA355 easy to machine?
Reasonably — machinability is rated good (55/100, worse than 67% of polyurethane grades). Drills and mills cleanly with sharp, high-rake tools and light cuts; avoid heat build-up above ~50 °C which softens and smears the part.
Can PP-Like SLA355 be welded?
Not readily — weldability is rated not recommended (5/100). Thermoset — cannot be heat welded; join with cyanoacrylate, epoxy or fresh resin cured under a 405 nm lamp.
What surface finishes work on PP-Like SLA355?
Sands and primes well; use filler primer plus 2K clear or paint, and always add a UV-blocking topcoat because bare parts yellow and embrittle in sunlight.
Can PP-Like SLA355 be formed, bent or molded?
Printed only by vat photopolymerization; keep exposure and layer settings tuned, then wash briefly in IPA and post-cure warm (50–60 °C) to reach rated toughness without over-embrittling.
What is the maximum service temperature of PP-Like SLA355?
PP-Like SLA355 is rated for continuous use to about 50°C (122 °F), and briefly to 70°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in PP-Like SLA355?
Yes — PP-Like SLA355 is available for urethane casting with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Durable / Tough photopolymer resin technical data sheets — Formlabs (2024)
- Somos polypropylene-like SLA resin data sheets (9120 / Evolve class) — Covestro (DSM Somos) (2023)
- Accura SLA resin family data sheets — 3D Systems (2023)
- eSUN / Siraya Tech PP-like 405 nm resin TDS — eSUN, Siraya Tech (2024)
- ASTM D638 / D790 / D256 / D648 test methods for plastics — ASTM International (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.