How to Control the Surface Flatness of Double-Curved GRC Panels?

Surface flatness control of double-curved GRC panels is a key link in ensuring both the architectural visual effect and structural performance. Based on 28 years of production experience, Qinglong Group holds that premium double-curved GRC panels should have a flatness deviation of ≤3mm/2m and a joint height difference of ≤1mm. This standard is achieved through triple control of mold precision, forming process, and curing measures.

Mold precision is the foundation of flatness. The surface error of double-curved molds must be ≤±1mm, with five-axis CNC machining used to ensure accuracy. In the "Chinese Red Lantern" project of the Wuhan Han Show Theatre, Qinglong Group inspected the molds through 3D scanning and kept the cumulative error within ±2mm. Epoxy resin was selected as the mold material, with a thermal deformation coefficient of ≤1.5×10⁻⁵/℃ to prevent temperature changes from affecting precision. Molds are maintained regularly and retain high precision even after 200 uses.

Precise control of the forming process. Robotic arms spray the GRC slurry at a stable pressure of 0.4-0.6MPa and a moving speed of 3-5m/min. In the Hainan International Convention and Exhibition Center project, Qinglong Group optimized the vibration parameters—a frequency of 50-60Hz and a duration of 30-45 seconds—to ensure dense compaction without air bubbles. Vacuum dewatering technology further improved surface densification, achieving a flatness compliance rate of over 99%.

Deformation prevention during curing. Custom supporting racks are used to prevent deformation caused by self-weight. The temperature difference in curing kilns is controlled within ±2℃, and humidity is kept at ≥95%. Through whole-process monitoring, Qinglong Group ensures that double-curved GRC panels maintain excellent flatness from production through installation.