High-temperature resins are photopolymers for SLA and DLP printing that are formulated to keep their stiffness at elevated temperatures. After UV post-cure and, for most grades, an additional thermal post-cure, their heat deflection temperature (HDT) ranges from roughly 100 °C to 250 °C or more at 0.45 MPa, compared with about 50–75 °C for standard resin. Unfilled grades print with the same fine detail and smooth surfaces as other resins; ceramic- or glass-filled grades push stiffness and HDT further but leave a matte, stone-like surface.
Choose high-temperature resin when a detailed printed part must withstand heat: prototype and low-volume injection mold inserts, thermoforming tools, fixtures near heat sources, and parts for hot air, hot water or gas flow testing. The trade-off is brittleness. The densely crosslinked network that resists heat leaves very little elongation, so these resins chip, crack and break under impact or clamping loads more easily than standard resin. Through Uretyco's partner network, high-temperature resins are offered for SLA and DLP printing; grade, feasibility and lead time are confirmed during quote and order review.
Mechanical and physical properties
| Property | Typical value | Notes |
|---|---|---|
| Heat deflection temperature (0.45 MPa) | ≈ 100–250 °C or more | After thermal post-cure; strongly grade-dependent. Filled grades reach the top of the range. |
| Heat deflection temperature (1.8 MPa) | ≈ 80–130 °C | Many unfilled grades; filled grades can be higher. Compare grades at the same load. |
| Tensile strength | ≈ 45–75 MPa | Fully post-cured; filled grades at the upper end. |
| Elongation at break | ≈ 1–4% | Very low; parts fail without yielding. |
| Tensile modulus | ≈ 2.5–4 GPa | Unfilled; ceramic- or glass-filled grades ≈ 7–11 GPa. |
| Impact strength (notched Izod) | ≈ 15–25 J/m | Low; similar to or below standard resin. |
| Density | ≈ 1.15–1.25 g/cm³ | Unfilled; filled grades ≈ 1.6–1.8 g/cm³. |
| Thermal expansion | ≈ 60–80 µm/m·K | Unfilled; considerably lower in filled grades, which helps mold inserts hold their shape. |
| Max. service temperature | Below the HDT | Short exposures can approach the HDT; parts under sustained load should stay well below it. |
| Flammability | Usually not rated | Most grades carry no UL 94 rating; flame-retardant photopolymers are separate grades. |
| UV stability | Poor | Yellows and embrittles in sunlight; not intended for outdoor use. |
Typical values for fully post-cured high-temperature resins, including the thermal post-cure most grades require. Properties differ widely between grades and depend on the post-cure schedule, wall thickness and orientation. Check the datasheet of the grade named in your quote and validate parts at their real temperature and load.
Printing with SLA and DLP
High-temperature resins print on the same SLA and DLP machines as other resins, but they are more viscous and less forgiving. Parts are washed, post-cured with UV light and, for most grades, baked in an oven on a schedule set by the resin supplier to reach the rated HDT. The thermal cure adds hours to the process and can move thin or unevenly thick features. Design and ordering points:
- Thermal post-cure: the datasheet HDT usually assumes it. If your part needs the top of the range, state the operating temperature so the partner applies the full cure schedule.
- Brittleness: add fillets to internal corners, avoid thin cantilevers and sharp notches, and keep walls thicker than for standard resin; about 1.5–2 mm is a sensible floor for parts that are clamped or handled.
- Distortion: large flat areas and long, slender sections can warp during the thermal cure. Uniform wall thickness and ribs reduce the risk; flag faces where flatness is critical.
- Fasteners and inserts: tapped threads crack easily. Heat-set inserts do not work because the cured resin does not melt; use bonded or press-fit inserts, or through-bolts with washers.
- Mold inserts: use generous draft, ideally 2° or more, avoid deep thin cores and tall thin ribs, and design the inserts to fit a metal mold base.
- Hollow parts and drain holes: the rules for standard resin apply. Enclosed cavities trap liquid resin, which can seep out or crack the part during the thermal cure.
Tolerances and surface
Without a drawing tolerance, Uretyco applies the SLA default of ±0.2 mm or ±0.2%, whichever is greater; actual results vary with technology, orientation, part size, supports and post-processing, and fit-critical features should be tested before production. High-temperature resins add shrinkage and possible distortion from the thermal post-cure, so mold cavities, bores and sealing faces that need precise dimensions are often finished by light machining or reaming after curing. Unfilled grades give the smooth surfaces typical of resin printing; filled grades have a fine matte texture.
Finishing options
Finishing follows the complete post-cure, because the thermal cycle can affect coatings and dimensions. Typical options:
| Finish | Effect | Notes |
|---|---|---|
| Supports removed, lightly sanded | Lowest cost | Support removal can chip brittle edges; small nubs remain. |
| Fully sanded | Uniform surface | Wet sanding is preferred; removes support marks before polishing or coating. |
| Polished mold surfaces | Better release and gloss on molded parts | Labor-intensive; molded parts copy any texture the insert has. |
| Machined or reamed features | Precise bores, fits and sealing faces | Machines like a brittle plastic; filled grades wear cutting tools. |
| Painting or coating | Color, marking | Check the coating's own temperature rating, which is often below the resin's HDT. |
A part that keeps its shape at 200 °C can still crack from a dropped tool, an over-tightened screw or a clamp. If the part must take impact, snap together or carry load while hot, compare PEI, PEEK or MJF PA12 before choosing a high-temperature resin.
Cost and lead-time drivers
High-temperature resin parts are priced like other resin parts, with a few additions:
- Resin cost: high-temperature grades cost considerably more per liter than standard resin, and filled grades more again, so part volume weighs more heavily.
- Thermal post-cure: the oven cycle adds hours to every order and is usually run in batches, which affects scheduling.
- Availability: fewer partners run these resins, and some grades need specific printers; feasibility and lead time are confirmed during quote and order review.
- Orientation and supports: build height drives print time, and support-heavy orientations add resin and careful manual removal.
- Finishing: polishing mold surfaces and machining critical features are manual steps and often the largest cost on tooling inserts.
High-temperature resin vs. other options
| Material and process | Heat resistance | Toughness | Surface and detail | Best for |
|---|---|---|---|---|
| High-temperature resin (SLA, DLP) | HDT ≈ 100–250 °C or more at 0.45 MPa | Low; brittle | Excellent | Mold inserts, hot air and fluid test parts |
| Standard resin (SLA, DLP) | HDT ≈ 50–75 °C at 0.45 MPa | Low; brittle | Excellent | Cosmetic models at room temperature |
| PEI (ULTEM), FDM or CNC | Continuous use ≈ 170 °C | Good; FDM parts weaker across layers | FDM: visible layers; CNC: machined finish | Functional hot parts, flame-retardant parts |
| PEEK (CNC, FDM) | Continuous use ≈ 250 °C | Very good | FDM: visible layers; CNC: machined finish | Loaded parts in heat and chemicals |
| PA12 (MJF) | HDT ≈ 150–175 °C at 0.45 MPa; ≈ 85–95 °C at 1.8 MPa | Very good | Slightly grainy | Tough functional parts up to ≈ 80–100 °C |
HDT alone does not decide the choice. A high-temperature resin is the right fit when fine detail, smooth surfaces and stiffness at temperature matter and the part sees little impact. When the part carries load or impact while hot, PEI or PEEK is the safer choice, and below about 100 °C MJF PA12 is often sufficient.
When not to choose high-temperature resin
Parts that take impact, snap-fit loads or clamping forces: the resin is brittle; use PEI, PEEK or PA12. Long-term loaded service close to the HDT: resin parts creep and soften. Production molds for thousands of parts: use aluminum or steel tooling. Applications that require a flammability rating: most grades carry no UL 94 rating. Outdoor or sunlit use. Food-contact, medical or skin-contact use: suitability depends on a certified grade, validated processing and your own regulatory assessment, and standard high-temperature grades are not intended for it.
Typical applications
- Prototype and low-volume injection mold inserts for lower-temperature thermoplastics.
- Thermoforming and vacuum-forming molds.
- Hot air, hot water and gas flow test parts: nozzles, ducts, manifolds and housings.
- Fixtures, holders and masks used near heat sources or in curing ovens, within the rated temperature.
- Molds for casting and heat-curing silicones, polyurethanes and waxes.
- Prototype housings and brackets for lighting, heating and under-hood environments.
Specifying high-temperature resin on Uretyco
- 1Upload STL, 3MF or STEP
Use a fine mesh. For mold inserts, a STEP file and a 2D drawing make it easier to review draft, parting faces and critical dimensions.
- 2Select high-temperature resin and state the temperature
Give the operating temperature, load and exposure time so that a grade with a suitable HDT is matched. Grade and lead time are confirmed in the quote.
- 3Mark critical faces and fits
Identify mold cavities, sealing faces and bores so supports stay off them and machining allowances can be added where needed.
- 4Choose finishing
State whether mold surfaces need polishing, bores need reaming, or inserts must be fitted after printing.
- 5Review the quote
Check the proposed grade, post-cure and lead time; specialized grades may need manual review before the order is confirmed.
FAQ
What does the HDT value mean for my part?
HDT is the temperature at which a standard test bar deflects by a defined amount under a fixed load, measured to ISO 75 or ASTM D648 at 0.45 MPa or 1.8 MPa. It is a comparison value, not a service rating. The real limit of a part depends on its load, wall thickness and exposure time, so compare grades at the same test load and validate parts at the operating temperature.
How many parts can a printed mold insert produce?
It depends on geometry, the molded material and the molding parameters. Simple inserts with generous draft, used with lower-temperature thermoplastics such as PP, PE or TPE, typically last from a few dozen to a few hundred shots. Higher-temperature or glass-filled materials, deep thin cores and sharp features shorten insert life sharply. For larger quantities, aluminum tooling is the next step.
Is there a high-temperature resin that is also tough?
Some grades, including certain dual-cure resins for DLP, combine a moderate HDT of around 100–130 °C with clearly better elongation and impact strength. They give up the top of the temperature range and are less widely available. If the part must be both heat-resistant and tough, consider printed or machined PEI or PEEK, or MJF PA12 below about 100 °C.
Related resources
- Standard SLA ResinGeneral-purpose resin for room-temperature models.
- PEI (ULTEM)Tough high-temperature thermoplastic for FDM and CNC.
- PEEKFor loaded parts at up to about 250 °C.
- PA12 (Nylon 12)Tough powder-bed parts for moderate heat.
- Bridge ProductionSoft tooling and the step from prototype to volume.
- 3D PrintingTechnologies, files and cost drivers.
Related materials
Plastics
Standard SLA
General-purpose photopolymer for SLA and DLP printing: the smoothest surfaces and finest detail of any common 3D printing process, but brittle and heat-sensitive. The default for cosmetic prototypes, detailed models and casting masters.
Plastics
Clear Resin
Unpigmented photopolymer for SLA, DLP and MSLA that prints translucent and becomes close to transparent after sanding and polishing or a clear coat. For see-through prototypes, fluidic models and light covers; brittle and prone to yellowing.
Plastics
Dental Resin
Photopolymers for dentistry: accurate model resins and biocompatible grades for guides, splints and temporary crowns. Use in the mouth depends on the certified resin, a validated printer and post-processing workflow, and the device maker's regulatory duties.
Plastics
Tough Resin
Engineering photopolymers formulated to behave like ABS or polypropylene: far more impact- and fatigue-tolerant than standard resin, with the same smooth surface and fine detail. For snap-fits, enclosures, jigs and functional prototypes at room temperature.
Elastomers
Flexible Resin
Soft, rubber-like photopolymers from about Shore 50A to 80A that bend, stretch and spring back. For soft-touch prototypes, small seals, grips and fine elastic details; less tear- and abrasion-resistant than TPU or silicone.
Plastics
ABS-Like Resin
Toughened photopolymer, mainly for MSLA printers, that is less brittle than standard resin while keeping fine detail and smooth surfaces. For handled and assembled prototypes, housings and detailed models; not a substitute for real ABS.
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