Putzmeister has introduced the "Spray-Sense" intelligent profile control system for its SPM 5007 E series concrete spraying robots, targeting the underground tunneling sector. In traditional wet-mix shotcrete application, achieving the design concrete thickness on uneven rock surfaces relies heavily on the nozzleman's visual estimation and manually placed survey pegs. This often results in uneven application-under-spraying leaves structural weak points, while over-spraying wastes expensive concrete and accelerates material rebound.
The Spray-Sense system integrates a "High-Speed 3D Laser Profiler" mounted on the spraying boom. Before spraying begins, the laser scans the raw rock face and generates a digital surface model. As the spray boom moves across the face, the laser continuously scans the freshly applied concrete. The engineering innovation is the "Dynamic Nozzle Pitch Algorithm." The system calculates the exact distance from the nozzle to the rock face in real-time. By dynamically adjusting the nozzle's pitch and yaw via servo-hydraulic cylinders, it ensures the concrete spray always impacts the surface at the optimal 90-degree angle. This perpendicular impact maximizes adhesion and drastically reduces rebound (material that bounces off the surface and is wasted).
Furthermore, the system features a "Rebound Rate Radar" mounted at the boom's base. By measuring the velocity and mass of aggregate particles bouncing back off the newly sprayed surface, the ECU calculates the actual compaction and adhesion rate. If the rebound rate exceeds 15%, the system automatically adjusts the concrete accelerator dosage and reduces the spraying pressure. This closed-loop monitoring ensures strict adherence to the 3D design profile, reducing concrete waste by 22% and completely eliminating the need for manual thickness spot-checks.
