What Are the Processing Differences Between Single-Curved GRC Panels and Double-Curved GRC Panels? Curved Surface Forming and Qinglong Group's Shaping Technology Grading

The difference in processing between single-curved GRC panels and double-curved GRC panels is essentially a generational gap between "developable surfaces" and "non-developable surfaces" in terms of mold technology, forming processes, and production control. Drawing on extensive experience from double-curved landmark projects (such as the Wuhan Han Show Theatre and the Hainan Convention & Exhibition Center), Qinglong Group has summarized the core differences: molds for single-curved panels (such as cylindrical and conical surfaces) can be machined with 3-axis CNC, with lower cost and relatively simple production; molds for double-curved panels (such as spherical and saddle surfaces) must be machined with 5-axis CNC to achieve high precision, and they pose extreme challenges to slurry rheology, fiber distribution, and demolding technology. In the "Flowing Cloud" double-curved curtain wall project at the Nanning New Media Center, we successfully achieved continuous transitions of complex double-curved surfaces with a minimum radius of curvature of R=800mm through parametric design optimization, 5-axis mold machining, and robotic directional spraying. Shape complexity directly determines the technical difficulty and cost.

A World of Difference in Mold Design and Manufacturing

The mold surface of a single-curved panel can be milled through the linear and circular interpolation movements of a 3-axis machine, with relatively simple programming. In contrast, a double-curved panel mold is a complex freeform surface in three-dimensional space that must be machined on a 5-axis simultaneous machining center, where the tool's continuously changing spatial orientation envelops the form. This places extremely high demands on machine precision, toolpath planning, and programming capability, and mold costs are typically 2-5 times those of single-curved molds.

Challenges in Forming Processes and Production Control

During spraying or casting, slurry flow on a single-curved mold is relatively controllable. On a double-curved mold, however, especially in areas with large Gaussian curvature variation, the slurry can easily flow unevenly under gravity, resulting in inconsistent thickness or poor fiber orientation. We address this challenge by adjusting slurry thixotropy and using a robotic sprayer to spray along the surface normal direction. During demolding, the adhesion forces and stresses of double-curved panels are also more complex, requiring specially designed demolding systems.

Escalating Difficulty in Precision Inspection and Installation Coordination

Key dimensions of single-curved panels can be inspected using conventional methods. Double-curved panels must be inspected with a 3D laser scanner to obtain complete point cloud data for comparison against the design model. During installation, the spatial positioning of double-curved panels requires 3D coordinate layout with a total station, imposing extremely high installation precision requirements—an error in any single panel can compromise the smoothness of the entire curved surface.

Therefore, when choosing between single-curved and double-curved shapes, it is essential to fully recognize the enormous differences in technology, cost, and schedule behind them. With its comprehensive curved surface technology capabilities, Qinglong Group can provide customers with complete solutions ranging from economical single-curved to artistic-grade double-curved products.