Architectural planning models subjected to public-exhibition fire safety review

In planning-department submittals, ECO FIL-A-GEHR Wood is processed as a monomaterial massing component rather than as a structural substitute for timber, MDF or concrete. The compounded filament is a wood-filled PLA-based system with a wood fibre fraction in the 20–30 wt% range in a PLA carrier; this fibre fraction is pre-compounded and is not a downstream formulation variable. The printed model core is produced at 100 wt% filament feed in single-nozzle extrusion systems; when transparent PETG or clear PLA window inserts are integrated, the wood-filled filament is constrained to 70–80 vol% of the total printed volume, with the remaining volume reserved for glazing bars, because differential shrinkage between filled and unfilled resins can open visible gaps at mullion transitions. Build settings on enclosed industrial extrusion platforms are held at a nozzle setpoint of 195–215 °C, a heated-bed setpoint of 55–60 °C, and layer heights of 0.20–0.25 mm for massing models. Print-farm operators running Bowden-fed machines with brass 0.40 mm nozzles observe intermittent clogging after 18–24 h of continuous wood-composite extrusion; conversion to direct-drive extruders with hardened tool-steel nozzles of nominal bore 0.60 mm maintains melt pressure without hourly purging because the larger bore passes fibre clusters that would accumulate behind a 0.40 mm brass orifice. Dimensional acceptance on assembled models is recorded against linear tolerance class m or c from ISO 2768-1:1989. Public-exhibition fire safety: when a model is positioned in an escape corridor or public atrium, venue fire officers may request a single-flame source test report to EN ISO 11925-2:2020; the material is not classified under EN 13501-1:2018 and must not be described as fire-rated. Terminal part types include site context models, planning consultation maquettes, urban-scale massing blocks, and public consultation display units.

When does wood-filled PLA filament replace machined MDF in furniture form studies?

Replacing machined MDF in furniture form studies with ECO FIL-A-GEHR Wood shifts the process bottleneck from CNC hold-down force and tool wear to melt-pressure stability at the nozzle and post-print abrasive sanding behaviour. The filament is used as the full-shell feedstock at 100 wt% of printed components; moisture-curing polyurethane adhesives or two-component acrylic filler contribute 5–8 wt% of the final assembled prototype mass only at bonded seams and filled grain lines, without modifying the base-polymer formulation. Large-format fused-filament systems with build envelopes above 800 mm in the long axis and heated molten zones of at least 30 mm are operated with 0.60 mm hardened tool-steel nozzles, extrusion temperatures of 200–220 °C, enclosure air temperatures of 35–40 °C, and a heated-bed setpoint of 55 °C; these conditions prevent corner lifting on chair-shell profiles and table-edge mock-ups where the long-axis thermal contraction of wood-filled PLA otherwise produces measurable end warp of 0.3–0.6 mm per 500 mm span. Because the wood fibre reduces the ductility of the PLA matrix, printed shells and armrests are tested for form, sandability, and ergonomic review; mechanical characterisation is limited to comparative values from ISO 527-2:2012 tensile and ISO 178:2019 three-point flexural tests, while final product qualification remains anchored to EN 16139:2013 for non-domestic seating or EN 1728:2012 strength and durability test methods. Prototypes are not certified as final furniture. Post-print processing includes sanding from 120 to 220 grit, grain filling with waterborne acrylic filler, and matte clear coating at a dry-film thickness of 40–60 μm; these steps produce a wood-like surface for client review but do not improve load-bearing capacity. Terminal part types include chair shells, armrests, drawer pulls, table bases, shelving brackets, and decorative wall-panel form studies.

The melt-viscosity response of wood-filled PLA imposes a narrower extrusion window than unfilled PLA; at nozzle temperatures below 200 °C, the melt develops fibre-induced shear thickening, while above 230 °C the wood fibre begins browning and generates volatile degradation products that raise part porosity. This is observed on production-scale furniture model lines as an extrusion multiplier shift of ±0.02 between spool lots; operators compensate by adjusting flow rate in slicer profiles rather than increasing temperature. Batch-to-batch variance in wood fibre moisture is controlled by drying at 45–55 °C for 4–6 h before printing, and filament buffer sensors on large-format machines prevent sudden tension spikes when spool drag increases. Amine-catalysed epoxy joinery fillers are incompatible with unsealed wood-filled PLA surfaces because residual moisture and hydroxyl groups in the cellulosic fibre produce interfacial amine blush and reduce bond strength; the surface must first be sealed with a waterborne acrylic barrier.

Point-of-sale display builders process ECO FIL-A-GEHR Wood at nozzle temperatures of 190–210 °C and a heated-bed temperature of 50–55 °C; the feed is maintained at 100 wt% of the display structure, while transparent polycarbonate or PETG windows are limited to 15–20 vol% of the assembled unit to keep wood-grain visual continuity across the front face. In print-cell production environments with relative humidity above 50%, the filament is pre-dried at 45–50 °C for 4–6 h; moisture above 0.03 wt% audibly presents as micro-popping during extrusion and visibly increases surface porosity on flat shelf faces after staining. Compliance for the temporary point-of-sale article is assessed under Directive 94/62/EC packaging and packaging waste only when the display is moved as a packaging or transit unit; permanent retail fixtures are subject to workplace emission screening according to DIN EN 16516:2020-10 if the printed object is placed in an enclosed retail environment, and SVHC communication obligations under REACH Article 33 apply to imported articles that contain candidate-list substances. Production process: parts are printed at 0.20 mm layer height with gyroid infill of 15–20%, sanded from 150 to 220 grit, stained with waterborne wood stain, and clear-coated with acrylic matte lacquer at a dry-film thickness of 40–60 μm. Large countertop displays are split into interlocking segments with dovetail joints and solvent-free adhesive on the bond line. Terminal product types include shelf-edge displays, countertop risers, trade show fixtures, window display props, subscription-box stands, and cosmetic launch units.

Automotive interior styling buck verification outside production-material homologation

At the pre-tooling design review gate, interior styling studios use ECO FIL-A-GEHR Wood as a visual surrogate that can be sanded, grained, and coated to mimic production trim before cutting steel tooling. The material is printed at 100 wt% of the visible buck surface; polyester or acrylic sealer is applied at 2–5 wt% of the final coated part mass, with primer dry-film thickness of 30–50 μm and grain-effect topcoat of 50–80 μm depending on the grain depth of the reference production part. High-resolution enclosed extrusion platforms are configured with 0.25 mm nozzles, 0.12–0.15 mm layer heights, and print speeds of 35–45 mm/s; larger door-panel sections are segmented along Class-A surface boundaries and joined with solvent-free polyurethane adhesive rather than printed as monolithic skins. Because the part may be displayed in design review rooms, flammability is screened by horizontal burn rate to ISO 3795:1989, odor by VDA 270, and gravimetric fogging by DIN 75201; these tests are comparative risk screens for styling models and do not constitute production-material homologation under FMVSS 302 for a final vehicle-interior component. Process tensions arise at the interface between filled PLA and automotive filler systems: if sealer is applied before surface moisture has equilibrated, micro-cracking occurs along sanded wood-fibre clusters within 24–48 h; the workpiece is therefore conditioned at 23 °C and 45–55% relative humidity for 12 h after sanding before topcoat application. Amine-containing polyester body fillers are not applied directly to unsealed wood-filled PLA because moisture at the cellulosic interface can generate amine blush and adhesion loss. Terminal part types include dashboard trim appearance models, door panel inserts, centre console surrounds, seat switch bezels, and interior mirror triangle covers for design review and ergonomic assessment.

Operational boundary: the wood-filled PLA styling buck is not placed in direct sunlight or in a vehicle cabin during hot soak because the heat deflection temperature of the PLA matrix limits dimensional stability above 50–55 °C; design studios therefore keep styling models in climate-controlled review rooms. The material is not approved for final vehicle interior use, and any test report generated on a printed styling buck is restricted to visual review purposes.

Museum fabrication departments evaluate ECO FIL-A-GEHR Wood for artefact replicas and interactive educational models only when the object is displayed indoors and separated from direct handling by a barrier; the filament is printed at 100 wt% of the replica matrix, with protective epoxy or polyurethane coatings accounting for 3–8 wt% of the completed exhibit mass. In children’s areas, migration of certain elements is tested to EN 71-3:2019+A1:2021; general exhibit surfaces are additionally screened for indoor volatile organic compound emissions using ISO 16000-6:2021. The reproduction workflow begins with structured-light or photogrammetric scanning, followed by mesh repair and slicing at 0.10–0.15 mm layer height for fine surface texture; internal gyroid infill is set to 15–25%, with 100% solid top and bottom layers to resist display handling. Sanding proceeds through 240–400 grit, grain filling uses waterborne acrylic filler, and final two-component topcoat is applied at 60–80 μm dry-film thickness. Moisture-induced swelling is controlled by sealing all surfaces; unsealed bottom surfaces of exhibit bases have shown dimensional growth of 0.2–0.4% after 72 h at 65% relative humidity, which is sufficient to open a visible seam between printed base and glass display case floor. Terminal part types include artefact replicas, tactile teaching models, botanical and anatomical enlarged models, exhibit plinths, diorama components, and gallery-scale interpretive models.

If film and theatre props require wood grain on curved monolithic forms

For film and theatre prop shops, the primary constraint is not mechanical strength but the ability to create curved monolithic wood-grain forms that can be sanded and painted without veneer delamination. ECO FIL-A-GEHR Wood is printed at 100 wt% of the prop body; flexible urethane or acrylic protective coatings account for 5–10 wt% of the finished prop mass, and internal armature rods may be added but do not alter the printed polymer fraction. Medium-format extrusion systems with 0.60 mm hardened nozzles and layer heights of 0.16–0.20 mm are used for prop bodies, while 0.25 mm brass or hardened nozzles are reserved for facial or small-detail components below 100 mm. A production bottleneck observed on stage-arts lines is the tendency of wood fibre to accumulate around twin-gear extruder hobbs when filament tension exceeds 1.0 kg; spool holders are therefore converted to low-drag bearing mounts, and reverse-Bowden guides with inner diameters of 4 mm are used to reduce biting. For set dressing in public assembly spaces, local fire marshals may request a comparative burn test to UL 94 HB; the printed prop is not certified as a construction material under DIN 4102-1 class B2 and must be coated with an approved flame-retardant lacquer where ignition sources are present. If the prop is used by child actors, migration of certain elements is checked against EN 71-3:2019+A1:2021; for general adult use, SVHC communication under REACH Article 33 remains the relevant article-level obligation. Terminal prop types include stop-motion armature bodies, stage weapon grips and scabbards, decorative architectural set pieces, mimic wood beams, and painted character masks.