A photopolymer formulation identified as DruckWege TYPE S STANDARD Basic Model UV Resin is supplied as a single-component, medium-viscosity liquid intended for masked stereolithography, digital light processing, and monochrome LCD-based additive manufacturing systems operating in the 385–405 nm UV-A emission band. The TYPE S STANDARD designation refers to a rigid, general-purpose acrylate/methacrylate matrix with a non-filled formulation and a photoinitiator package tuned for the irradiance levels typical of desktop LCD printers. In the cured state the material exhibits a hard, glassy response with low elongation and moderate heat deflection; it is therefore positioned for dimensionally stable prototype parts, master patterns, and non-load-bearing functional fixtures rather than for flexible closures, high-temperature under-hood components, or castable jewelry patterns. The uncured liquid has a nominal viscosity of 150–250 mPa·s at 25 °C when measured according to ISO 3219, and the cured resin density is 1.08–1.15 g/cm³ by ISO 1183-1. The product is filled into amber high-density polyethylene bottles of 1 kg, 5 kg, and 10 kg, and the container should be rolled or gently agitated for 2 min before each build because low-shear settling of photoinitiator residues can occur after prolonged storage. The resin is not supplied as a ready-to-use flexible, water-washable, or biocompatible material; those performance classes are addressed by separate DruckWege grades. The basic formulation contains no volatile solvent, and the closed-cup flash point is above 100 °C when measured by ISO 2719, which reduces vapor accumulation in unventilated small-format printers but does not eliminate the requirement for local exhaust ventilation.

What specifications define the TYPE S STANDARD Basic Model?

The table below summarises representative lot-average values for the Basic Model after 30 min of post-cure under a 405 nm LED chamber at 8–12 mW/cm². Tensile and flexural specimens were printed at 50 µm layer thickness and tested in the X-Y orientation. Property values are not batch-specific release limits; production certificates of analysis should be consulted for acceptance criteria. The viscosity range reflects a shear-thinning response: low-shear readings at 10 s⁻¹ can reach 300–450 mPa·s, while the high-shear plateau at 100 s⁻¹ falls to 150–250 mPa·s. This behavior is intentional for recoat uniformity on gravity-fed vat systems, but it also means viscosity must be measured under controlled shear-rate conditions, not with a simple spindle at an unspecified speed.

Post-cure is not optional for mechanical stability. Parts removed from the build platform retain an under-converted surface layer that can plasticize the bulk network if the solvent wash is delayed beyond 20 min. The standard post-cure sequence is a two-stage immersion wash in 99% isopropanol or tripropylene glycol monomethyl ether for 2–3 min per stage, followed by compressed-air drying at 1.5–2.0 bar and 30–60 min of uniform UV post-cure at 385–405 nm and 40–45 °C. When post-cure temperature exceeds 45 °C, minor dimensional growth of 0.2–0.4% has been observed in the Z axis due to thermal relaxation of polymerized layers; this is within the range expected for underfilled acrylate networks. The resin should not be post-cured in an oxygen-free chamber unless the chamber has active temperature control because exothermic chain growth can raise part surface temperature above the heat deflection limit. Oxygen inhibition at the surface produces a tacky layer during printing; this layer is removed by the solvent wash and does not indicate a defective build. Post-cure completeness can be qualitatively checked by Shore D hardness stability: parts that gain less than 3 Shore D points between 30 min and 60 min of post-cure are considered practically converted for non-critical applications.

Layer-Cure Kinetics and Exposure Latitude in the Basic Model

The working curve for the TYPE S STANDARD Basic Model under a 405 nm LED source shows a critical polymerization energy of 8–15 mJ/cm² and a nominal penetration depth of 0.08–0.14 mm for pigmented-grade batches. The reciprocal relationship between cure depth and logarithmic exposure implies that a 50 µm layer height can be exposed at 2.5–4.0 s when the measured irradiance at the vat surface is 4.0–4.5 mW/cm². On non-monochrome or aged LCD arrays with surface irradiance below 3.0 mW/cm², the default exposure should be increased to 5–7 s to maintain interlayer adhesion. Burn-in layers for build plate adhesion typically require 20–30 s of exposure at the same irradiance, depending on platform coating, platform roughness, and chamber temperature. Published data for this specific configuration are limited when using high-frequency grayscale anti-aliasing or dynamic exposure compensation in third-party slicers; validation on the target printer is required before production runs. The exposure window narrows with increasing layer height: at 100 µm, the difference between interlayer delamination and overcure-induced side blooming is approximately 1.5–2.0 s, so larger layer heights are not recommended for parts with fine vertical channels or thin walls below 1 mm.

In production-scale LCD arrays with a print area above 8.9 inches diagonal, the main process failure mode is not bulk cure but first-layer delamination caused by thermal shrinkage during the burn-in sequence. The resin reaches its green-state plateau only when the peel distance between the build plate and the fluorinated ethylene propylene film is maintained below 5 mm and the lift speed is kept at 40–80 mm/min for the first 10 layers. Above 80 mm/min lift speed, the vacuum-assisted separation can generate microvoids at the edge of large cross-sections; this is observed as white, chalky patches on the bottom surface. Batch-to-batch viscosity variation is specified as ±10% from the lot-average value. If viscosity exceeds 275 mPa·s at 25 °C, the resin may fail to recoat uniformly on 4K mono-LCD machines with a passive gravity-fed vat, leaving layer lines parallel to the tilt axis. The same high-viscosity condition can also increase the rest time needed for bubble disengagement after the build plate descends; bubbling is reduced by a rest time of 2–3 s after recoating, but resin with a viscosity above 275 mPa·s may require 5–8 s of rest for defect-free thin layers. High ambient humidity above 60% RH increases the equilibrium water content of the uncured resin, and the resulting build can show a soft surface and reduced interlayer adhesion if the resin is not pre-dried by resting over a desiccant bed for 12–24 h.

If storage temperature falls below 18 °C, viscosity and first-layer adhesion shift

The uncured resin must be stored in the original sealed container at 15–30 °C and protected from direct sunlight and incidental UV from fluorescent and LED room lighting. At storage temperatures below 18 °C, viscosity rises steeply and first-layer adhesion can shift by more than 25% relative to the room-temperature baseline; a warm-up period of 4–6 h at 22–25 °C is recommended before printing from cold inventory. Shelf life is 24 months from the date of manufacture when stored in the unopened original container. After opening, the resin should be used within 60 days because atmospheric moisture and oxygen can reduce photoinitiator efficiency. The liquid must not be mixed with amine-based additives, strong bases, or oxidizers; these can induce radical generation and exothermic gelling in the storage container. The uncured resin is classified as an irritant under CLP Regulation (EC) No 1272/2008; nitrile gloves and eye protection are mandatory, and work should be carried out under local exhaust ventilation. The product is manufactured under a quality system aligned with ISO 9001:2015, and the raw polymer matrix is screened against the restriction list in REACH (EC) No 1907/2006 Annex XVII. RoHS compliance to Directive 2011/65/EU applies to the cured polymer under the expected use conditions for the basic grade. The uncured resin has not been evaluated for chemical compatibility with every commercially available vat film; long-term storage in direct contact with polycarbonate or acrylic vat walls can cause surface crazing, so the original HDPE container or fluoropolymer-lined vats should be used.

Compared with other DruckWege UV resin grades, the TYPE S STANDARD Basic Model occupies the center of the rigid photopolymer range. The water-washable variant drops the solvent-wash step but typically shows higher equilibrium moisture uptake and lower heat deflection temperature; the high-temperature variant requires a post-cure profile of 60 min at 60 °C and delivers HDT values above 100 °C, but its higher viscosity and stronger odor impose additional handling controls. The flexible variant is formulated to produce elongation at break above 40% and therefore cannot be substituted directly in dimensionally stable tooling applications. The comparative data in the table below are representative ranges after each grade’s recommended post-cure cycle.

The TYPE S STANDARD Basic Model is not a universal replacement for these grades; it differs from high-temperature and flexible resins in cross-link density, urethane content, and photoinitiator concentration, which changes the slope of the working curve and the plateau conversion. In applications where acetone immersion or fuel exposure is required, the standard grade is not recommended because the cured network swells and loses dimensional stability. The water-washable grade is often selected for educational settings because solvent handling is reduced, but its lower HDT and higher moisture sorption can be unacceptable for precision jigs; the Basic Model retains a lower moisture uptake and better edge retention after solvent wash.

Wet-Sanding, Solvent Cleaning, and Dimensional Stability of Basic-Model Parts

Sanded and machined parts produced from the TYPE S STANDARD Basic Model exhibit a uniform glassy surface when wet sanded with 400–1000 grit silicon carbide paper under flowing water. Dry sanding is not recommended because the local frictional heat can exceed the glass transition temperature, causing surface smearing and loss of feature edge definition. The cured material has a water absorption at saturation of 0.8–1.4% after 24 h immersion at 23 °C following ISO 62; this is low enough for short-term water exposure but not sufficient for continuous outdoor weathering without a protective clear coat. Solvent resistance is moderate for isopropanol and ethanol, but ketone-based solvents such as acetone cause visible cracking within 15 min at 23 °C. Dimensional stability after post-cure is typically within ±0.2% of the digital model for part dimensions below 100 mm, with larger parts exhibiting an additional 0.1–0.2% linear shrinkage along the build plane if post-cured while still attached to the build platform.

For functional prototypes used in assembly jigs or low-pressure vacuum forming, the TYPE S STANDARD Basic Model can be considered only when the service temperature remains below 45 °C and the part is not exposed to halogenated hydrocarbons, strong alkaline solutions, or elevated humidity above 60% RH for more than 48 h. The material is not suitable for medical device body contact or food-contact use under FDA 21 CFR or EU 10/2011; no compliance statement is provided for those regulatory categories. Published data for this specific configuration is limited in the peer-reviewed literature; therefore, process qualification on the intended printer, vat film, and post-cure unit is required before use in serial production.