Kentstrapper Mille 3D Prints Class A Acoustic Panels for Architectural Retrofits

Italian printer manufacturer Kentstrapper has collaborated with the University of Florence to produce a large-format 3D-printed acoustic panel that achieved Class A sound absorption in standardized testing. Developed for an architectural retrofit project named REVERSING, the panel combines calculated geometric forms with mineral wool insulation to improve speech intelligibility and reduce reverberation in school and office environments.

Technical Details of the Acoustic Panel

The research initiative, led by the university’s Department of Architecture, relies on parametric modelling created in Rhinoceros and Grasshopper. The resulting design features a sinusoidal profile with a variable-diameter hole pattern shaped entirely by acoustic calculations rather than visual aesthetics. Varying hole diameters and cavity depths allow the printed shell to function effectively alongside a rear mineral wool layer.

Production took place on a Kentstrapper Mille, an FDM system featuring a build volume of one cubic metre. The component was printed using PETG filament with a 0.8 mm nozzle and a controlled deposition rate to maintain structural stability across the corrugated surface. Because of the large dimensions, the final assembly is divided into eight sub-components measuring 860 by 344 mm each. Every sub-section consumed approximately 2.5 kg of material and required 56 hours of print time.

Standardized testing in a reverberation chamber according to ISO 354 showed that the installation reached a weighted sound absorption coefficient of 0.90, qualifying as Class A under ISO 11654 standards. Compared with a standalone mineral wool panel, the hybrid configuration reduced reverberation time by 41 percent at 500 Hz and 45 percent at 1,000 Hz, while improving the Speech Transmission Index from 0.47 to 0.52.

What This Means for South African Makers

Large-format additive manufacturing is steadily shifting away from basic prototyping and tooling toward certified functional components. While massive build volumes and long print times place this specific scale of architecture beyond typical desktop budgets, the underlying workflow offers valuable lessons. Using parametric tools like Grasshopper alongside standard FDM materials such as PETG demonstrates how makers and designers can create complex, performance-driven functional geometry for local commercial and educational spaces.

DC3D’s Take

Projects of this scale highlight the growing maturity of large-format FDM technology when paired with rigorous engineering validation. While printing a single acoustic panel over dozens of hours remains unfeasible for rapid high-volume manufacturing, the integration of algorithmic design with thermoplastic extrusion opens up distinct avenues for custom interior architecture and acoustic conditioning.