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

The core manufacturing differences between single-curved and double-curved GRC panels lie in mold complexity, forming processes, and precision control difficulty, which directly result in order-of-magnitude differences in production cost and efficiency. Single-curved panels (curved in only one direction) can use lower-cost GRP molds or simple wooden molds and be formed through troweling or spraying processes, with mold production taking about 3-5 days. Double-curved panels (curved in two directions), however, must use high-strength tooling-board molds or metal molds precision-machined by five-axis CNC, combined with robotic spraying technology featuring three-dimensional positioning; mold cycles require 7-15 days, and the skill demands on workers are extremely high. In the "Red Lantern" double-curved project for the Wuhan Han Show Theater, Qinglong Group mastered mass production technology for double-curved panels with a minimum curvature radius of R=300mm, controlling surface profile errors within ±1.5mm and demonstrating industry-leading capability in realizing complex curved surfaces.

The Vast Difference in Mold Technology

A single-curved mold can be approximated as a developable surface and is relatively simple to make. A double-curved mold, by contrast, is a non-developable complex three-dimensional surface that must be three-dimensionally milled on a five-axis machine driven by a digital model; it places extremely high demands on the strength, stiffness, and wear resistance of the mold material, and typically costs 3-5 times as much as a single-curved mold.

The Difference in Forming Process Precision

When producing single-curved panels, the material tends to flow downward under gravity, so the flow rate must be controlled. When forming double-curved panels, material flow over the three-dimensional surface is far more complex, making it very easy to end up with material shortage at concave corners or fiber buildup at convex corners. Qinglong Group adopts "path-programmed robotic spraying" to precisely control the material output and fiber orientation at every location, ensuring uniform product thickness and rational fiber distribution.

The Challenge of Precision Control and Inspection

Acceptance inspection of double-curved panels must use three-dimensional laser scanning to generate point cloud data for comparison against the original design model, whereas single-curved panels can be inspected with conventional measuring tools. This difference makes double-curved panel production more like precision manufacturing than traditional building material processing. Qinglong Group produces the two types of products on separate lines, ensuring process focus and optimized efficiency for each. Understanding these differences is the foundation for making sound styling choices and controlling budgets.