Differences in Mold Requirements Between UHPC Single-Curved Panels and Double-Curved Panels: Mold Difference Comparison and Adaptation Solutions

UHPC single-curved panels and double-curved panels differ significantly in their requirements for mold precision, materials, and manufacturing processes due to their different curved surface forms. Precisely matching the mold solution is key to ensuring the forming quality of components. Drawing on experience from curved surface projects such as the Shanghai Astronomy Museum and Guangxi New Media Center, Qinglong analyzes the mold differences between the two and the corresponding adaptation strategies.

I. Core Differences in Mold Precision Requirements

The difference in mold precision standards between single-curved panels and double-curved panels lies mainly in surface control and jointing requirements. For single-curved panels (single-curvature surfaces), the mold curvature radius error is ≤±3mm, surface flatness ≤0.8mm/m, and joint gaps ≤0.3mm. In Qinglong's single-curved panel project for the Yirui Biotechnology Building in Shenzhen, mold precision was executed to these standards, achieving good forming results. Double-curved panels (dual-curvature surfaces), with their more complex surfaces, have higher precision requirements: curvature radius error ≤±2mm, deviation of any point from the design model ≤1.5mm, surface flatness ≤0.5mm/m, and joint gaps ≤0.2mm. In the Guangxi New Media Center double-curved panel project, mold precision had to be verified through 3D laser scanning to ensure zero deviation. In addition, double-curved panel molds require extra control of surface torsion precision, with torsion error ≤0.3mm/m, to avoid twisting of components after forming.

II. Differences in Mold Materials and Structural Design

Material selection and structural design must match the complexity of the curved surface. Single-curved panel molds can use GRP molds or steel molds: GRP molds are lightweight and low-cost, suitable for small to medium batch production, while steel molds offer stable precision and are suitable for large-scale standardized production. Structurally, a single-piece integral mold or a small number of segmented pieces joined together is used, with joints fixed by simple bolts. Double-curved panel molds, given their variable surfaces, prefer high-strength steel molds to ensure rigidity and stability and prevent deformation during casting. Complex double-curved panels require multi-piece segmented molds, each piece sized ≤2m×2m, with joints double-fixed by positioning pins and high-strength bolts, plus rigid skeleton supports to prevent surface distortion. In Qinglong's double-curved panel project for the New World Century Plaza in Shanghai, this structural design was adopted, achieving mold jointing precision of 0.1mm.

III. Comparison of Mold Manufacturing Processes

Manufacturing processes must be adjusted according to surface complexity to ensure forming quality. Single-curved panel molds are made using "manual lofting + mechanical grinding" or simple CNC machining, with a relatively simple process and shorter cycle—about 3-5 days per set. Double-curved panel molds require an integrated process of "3D scanning + parametric design + CNC machining": first, design surface data is obtained through 3D scanning, then optimized via parametric modeling, and finally precision-machined on a five-axis CNC milling machine, with manufacturing cycles as long as 10-15 days per set. In Qinglong's double-curved perforated panel project for the Ouargla Hotel in Algeria, this process achieved precise replication of complex curved surfaces. In addition, double-curved panel molds require an added trial molding step, with mold precision adjusted based on trial-produced components, while the trial molding frequency for single-curved panel molds can be appropriately reduced.

IV. Differentiated Adaptation of Mold Costs and Maintenance

Cost and maintenance strategies must be formulated in line with mold characteristics. In terms of cost, single-curved panel molds, owing to simpler processes and lower material requirements, cost about 30%-50% of double-curved panel molds per set, with an even more pronounced cost advantage in batch production; double-curved panel molds, due to high-precision machining and complex structures, are more expensive, but costs can be amortized by increasing the number of reuses. In terms of maintenance, single-curved panel molds are simple to maintain, requiring only regular surface cleaning and flatness checks; double-curved panel molds require focused inspection of joint areas and surface integrity, with precision calibration every 5-8 uses, and steel molds need regular anti-rust painting to prevent corrosion from affecting precision. Through differentiated maintenance strategies, Qinglong extends the service life of both mold types, ensuring maximum production benefits.