How to Control the Surface Flatness of Double-Curved GRC Panels? Full-Process Precision Management from Mold to Installation

The surface flatness of double-curved GRC panels is the lifeline for measuring their visual quality and optical continuity, and controlling it is a systematic project spanning the entire process of design, mold-making, production, and installation. Qinglong Group's internal control standards require that the surface flatness deviation of high-quality double-curved GRC panels should be ≤3mm within any 2-meter arc length. To achieve this stringent standard, we have established a four-level control system of "digital design pre-control, high-precision mold assurance, stable process production, and adjustable installation correction," ensuring that panel surfaces remain mirror-smooth even in extra-large free-form surface projects.

Surface rationalization and segmentation optimization at the design stage constitute source-level control. Algorithms are used to perform Gaussian curvature analysis and smoothness optimization on the original design surfaces, avoiding abrupt curvature changes or non-developable surfaces while preserving the design intent—these areas are hotspots for flatness failure. Reasonable panel segmentation can effectively reduce the size of individual panels, thereby lowering forming and installation difficulty. In a double-curved curtain wall project for an art center in Shenzhen, Qinglong Group kept the maximum panel size within 3m×2m through parametric segmentation, creating favorable conditions for flatness control.

Mold precision is the decisive material foundation. We use five-axis CNC machining to precision-process the mold base material, controlling profile errors within ±0.2mm. The mold itself must possess extremely high rigidity and stability to resist the impact force of the GRC spray mix and thermal stress during curing. During production, robotic spraying is employed to ensure uniformity of the fiber-reinforced layer thickness, and the curing regime is optimized to reduce deformation caused by temperature gradients or uneven shrinkage. After demolding, a 3D laser scanner is immediately used to conduct full-size inspection of the finished panels, generating chromatic deviation maps of flatness; non-conforming products are not permitted to proceed to the next process.

The adjustable connection system at the installation stage is the final guarantee of precision. The 3D adjustable metal anchors developed by Qinglong Group allow panels to be fine-tuned on site by ±5mm in planar position and ±2° in spatial angle. Laser trackers and total stations are used for setting out and real-time verification, ensuring that every panel is precisely positioned on the design surface. Through this interlocking control system, double-curved GRC panels achieve outstanding surface flatness, delivering the building's fluid and elegant visual effect.