DruckWege TYPE D PRO UV Resin is a rigid urethane acrylate photopolymer intended for functional prototyping on 385 nm and 405 nm digital light processing, liquid crystal display, and masked stereolithography platforms. The material designation TYPE D PRO identifies the D-series rigid engineering grade in the DruckWege portfolio and is supplied as a single-component, unfilled formulation with a dynamic viscosity of 420 mPa·s at 25 °C per ASTM D2196-20. Liquid density is 1.12 g/cm³ at 25 °C per ASTM D4052-22; cured density is 1.18 g/cm³ per ISO 1183-1:2019. Cured specimens printed at 50 µm layer thickness and post-cured at 60 °C for 30 min under a 405 nm LED array at 2.0 mW/cm² yield the following typical values: tensile strength at break 58 MPa, tensile modulus 2.6 GPa, and elongation at break 6.5% per ASTM D638-14 Type IV; flexural strength 82 MPa and flexural modulus 2.4 GPa per ISO 178:2019; notched Izod impact 22 J/m per ASTM D256-10 Method A; heat deflection temperature 76 °C at 0.455 MPa and 61 °C at 1.82 MPa per ASTM D648-18; Shore D hardness 83 per ISO 868:2003.

Dynamic mechanical analysis at 1 Hz per ISO 6721-1:2019 shows a glass transition peak at 68 °C. Coefficient of linear thermal expansion between −20 °C and 40 °C is 72 µm/m·°C per ISO 11359-2:2021. Water absorption after 24 h immersion at 23 °C is 0.9% per ASTM D570-22.

These values are representative batch averages, not minimum specification limits. Mechanical strength on the Z-axis is typically 15% to 25% lower than XY-plane values because of interlayer boundary effects. Thin walls below 1.0 mm exhibit higher sensitivity to exposure drift and post-cure warpage.

Why Is Linear Shrinkage Reported as a Range Instead of a Single Value?

Linear shrinkage in photocured parts is governed by accumulated energy dose at the voxel boundary, not solely by the resin formulation. For TYPE D PRO, manual compensation factors of 0.8% to 1.5% are recommended across layer thicknesses from 25 µm to 100 µm, with the lower compensation applied to 25 µm layers and the upper compensation applied to 100 µm layers. A 50 µm layer printed at 10.8 mJ/cm² to 14.4 mJ/cm² on a 405 nm DLP system typically exhibits centerline shrinkage near 1.1% after post-cure. Exposure below 8 mJ/cm² produces incomplete vitrification and can leave tacky surfaces in recessed areas, while exposure above 18 mJ/cm² increases lateral overcure and causes closed holes to print undersized by 0.3 mm to 0.6 mm depending on diameter and depth-to-diameter ratio. Because shrinkage is directionally non-uniform, a single global scaling factor should not be used for both XY and Z compensation. Z-axis compensation of 0.9% to 1.3% is normally required in addition to XY compensation of 0.5% to 0.9% on dimensions larger than 25 mm.

On a production-scale DLP workstation with a 405 nm LED light engine delivering 4.0 mW/cm² to 5.0 mW/cm² at the build plane, the accepted layer exposure for 50 µm is 2.2 s to 3.0 s, equivalent to 8.8 mJ/cm² to 15.0 mJ/cm². Build platform temperature should be held at 25 °C to 30 °C; at 20 °C the dynamic viscosity rises to approximately 780 mPa·s, and recoating defects become more frequent on flat sections larger than 30 mm × 30 mm. Lift speed during separation should be 60 mm/min to 90 mm/min for print areas below 40 mm × 40 mm. Full-platform builds with cross-sections above 40 mm × 40 mm require a reduced lift speed of 45 mm/min to 55 mm/min and a separation delay of 0.3 s to 0.5 s to limit peel force. After printing, green-state parts should be washed in 99% isopropanol or tripropylene glycol monomethyl ether for 180 s to 300 s. Soaking beyond 600 s causes measurable surface softening and has reduced flexural strength by 5% to 8% on ISO 178:2019 specimens.

Dimensional accuracy on a calibrated 4K DLP printer with 100 mm × 62.5 mm build area is typically ±0.15 mm for features between 10 mm and 50 mm and ±0.25 mm for features between 50 mm and 100 mm after compensation. Hole diameters should be designed with an additional 0.25 mm to 0.40 mm on the radius for holes below 3 mm because light penetration into the surrounding polymer reduces opening size. Sharp external corners printed without fillets have shown a reduction in notched Izod impact from 22 J/m to 14 J/m when notch radius is below 0.1 mm. Functional housings, snap-fit latches, and fluid manifolds therefore benefit from radiused transitions and draft angles above 1° to reduce stress concentration and damage during support removal.

Oxygen-Inhibited Surface Tack and Post-Cure Equipment Requirements

TYPE D PRO contains urethane acrylate and aliphatic methacrylate components whose radical cure is retarded at the resin-air interface by molecular oxygen. On open-vat DLP and LCD systems, green-state surface tack remains after printing unless the part is washed and post-cured under conditions that exclude or dilute oxygen. A post-cure chamber with 405 nm LED panels providing 1.5 mW/cm² to 2.5 mW/cm² at the part surface and an internal temperature of 60 °C for 30 min to 45 min is sufficient for mechanical stabilization. Inert-gas post-cure under nitrogen with residual oxygen below 1% can reduce surface tack and increase Shore D hardness by 2 to 3 points but is not required for most functional prototypes. Post-cure doses above 6 J/cm² do not increase tensile modulus significantly, yet reduce elongation at break from 6.5% to 4.8% because of progressive crosslink densification. Use of UV-C sources below 280 nm is not recommended; high-energy UV-C creates a steep crosslink gradient at the surface and has caused visible microcracking on thin sections below 0.5 mm.

When TYPE D PRO is compared with other photopolymer classes used in prototyping, the key distinction is the simultaneous retention of tensile modulus above 2.0 GPa, HDT at 0.455 MPa above 70 °C, and notched Izod impact above 20 J/m. General-purpose model resins are easier to sand and finish but usually exhibit tensile modulus below 1.8 GPa, HDT at 0.455 MPa below 50 °C, and lower impact resistance. High-temperature rigid resins may achieve HDT above 120 °C but generally require heated vats above 35 °C because their viscosity exceeds 1,000 mPa·s, and they often fail in brittle fracture mode at notched Izod values below 10 J/m. Elastomeric resins provide 50% to 150% elongation and absorb impact energy but possess tensile modulus below 0.1 GPa, making them unsuitable for load-bearing brackets and dimensionally stable covers.

The comparison is based on publicly available technical data for general material classes and is not an interlaboratory test series. Direct substitution should be confirmed with application-specific testing under the intended build orientation, post-cure equipment, and service environment.

If Continuous Operating Temperature Is Required Above 55 °C

Heat deflection temperature at 1.82 MPa is 61 °C, but this value is a short-term deflection temperature under a specified bending stress and is not equivalent to a continuous service temperature. Under sustained load at 20% of ultimate flexural stress and 50 °C, creep compliance increases over 24 h; published data for this exact formulation beyond 500 h at elevated temperature are limited. Load-bearing parts that operate above 55 °C should therefore be validated with application-specific creep and stress relaxation testing before production use. Short-term exposure to 85 °C for 2 h can increase modulus through additional crosslinking but may produce dimension changes up to 0.4% in walls thinner than 1.0 mm. Aqueous service above 40 °C is not recommended because water absorption at 24 h is 0.9% per ASTM D570-22; combined heat and moisture can plasticize the urethane phase and lower tensile strength below the reported 58 MPa.

Short-term immersion tests at 23 °C per ASTM D543-21 show mass change below 0.5% after 24 h in 0.9% saline, 10% aqueous ethanol, and light mineral oil. Acetone, methyl ethyl ketone, and ethyl acetate cause visible surface attack within 5 min and are incompatible cleaning solvents. For technical assemblies exposed to gasoline splash or brake fluid, chemical compatibility screening should be performed because swelling and microcrack formation may occur before mass change exceeds 1%. The resin is not recommended for continuous outdoor use without a UV-stable coating; accelerated xenon arc exposure shows yellowing and a reduction in notched Izod impact after 200 h, although tensile modulus remains within 10% of the initial value.

The product is supplied in amber polyethylene containers and should be stored at 5 °C to 30 °C in the original sealed packaging. Shelf life is 12 months from date of manufacture; storage above 35 °C can increase viscosity by more than 15% and reduce cure response. The liquid resin is classified as a skin sensitizer under the CLP Regulation and must be handled with nitrile gloves, safety eyewear, and local exhaust ventilation. Cured parts are considered non-hazardous only after complete post-cure and removal of residual solvent. The material has not been qualified under FDA 21 CFR 177.2600 or ISO 10993-1 for food-contact or medical applications. RoHS compliance is documented under Directive 2011/65/EU as amended by Delegated Directive (EU) 2015/863, and REACH obligations follow Regulation (EC) No 1907/2006, including SVHC disclosure at 0.1% w/w.