In 3D concrete printing, a wall is built layer by layer. The key question is how firmly neighbouring layers bond. The joint strength depends, among other things, on the time gap between layers and the size of their contact area. At the Faculty of Civil Engineering, Brno University of Technology, we verified that enlarging the contact area by roughly 30% can increase interlayer strength by up to 70%. The challenge is that real-world conditions vary—concrete viscosity changes over time and the deposition interval fluctuates. Conventional print nozzles cannot flexibly respond to these changes. Our solution actively shapes the surface of the freshly deposited layer so the contact area is always tuned “on demand” to current conditions.

Device Description

At the heart of the solution is a special 3D concrete-printing nozzle with an integrated shaping strip. The strip has a comb-like profile and is guided vertically on the nozzle’s outlet face; its position is smoothly adjusted by a servomotor via a gear. This allows on-the-fly control of the groove depth formed on the layer surface—and thus the size of the contact area between layers. For easy servicing and adaptation to different mixes, the strip’s housing is screwed on, so the strip can be quickly replaced with a variant featuring a different number of grooves or a different geometry.

Expected Market

• Manufacturers of construction 3D printers and integrators of robotic cells—for new models and as an add-on module to boost print quality.
• Construction companies and R&D centres piloting 3D printing for load-bearing and non-load-bearing structures where homogeneity and repeatability are critical.
• Research and university laboratories focused on the rheology of cementitious composites and print-parameter optimisation.
• Pilot and demonstration projects (houses, small architectural elements, prefabrication) that must reliably handle variability in mixes and operating conditions.

Who the Final Product Is Ideal For

• Teams addressing interlayer strength who want to control it actively rather than rely on a “static” nozzle setting (adapting groove depth to viscosity and deposition interval).
• Operations with changing mixes or print tempos, where variability would otherwise lead to uneven properties across the structure.
• Applications emphasising the quality of the layer interface (arches, lintels, slender walls) where a larger contact area yields a measurable strength gain.

Protection Status

Utility Model CZ 38 510 U1 – Nozzle for a Device for 3D Printing of Concrete
Application No. 2025-42678 filed on 12 March 2025, registered on 15 April 2025. Owner: Brno University of Technology; inventors: Ing. Josef Válek, Ing. Arnošt Vespalec, Ph.D.

Tender for Licensee

Start: 1 September 2025

Expected evaluation of bids: 31 December 2025

Contacts

Technical information: Ing. Josef Válek, Ing. Arnošt Vespalec, Ph.D. 

Business and contractual information: doc. ing. Michal Kriška, Ph.D.

Please send price quotations and suggestions to the contact person listed above. Offers will be evaluated no later than the tender closing date; all applicants will then be informed of the result.