What Is the Minimum Curvature Radius Achievable for UHPC Single-Curved Panels?

The minimum achievable curvature radius of UHPC single-curved panels is a key indicator of a manufacturer's capabilities in material forming and mold technology. It is not a fixed value, but a dynamic limit constrained by multiple factors: material rheology, forming process, panel thickness, and mold precision. Based on extensive experiments and project practice, Qinglong Group can, under normal production conditions, achieve a stable production minimum curvature radius of approximately 500mm (for 10-15mm thin panels) to 1000mm (for 20-25mm standard panels). For example, in the "Flowing Cloud" design of the Nanning New Media Center, we successfully mass-produced UHPC single-curved panels with a curvature radius as low as 600mm, achieving graceful flowing lines. Pursuing smaller radii means facing the challenges of declining yield and sharply rising costs.

The Limits of Material Rheology and Plasticity

UHPC is a material with low fluidity and high viscosity. When the curvature radius is too small, the slurry encounters great resistance when flowing and filling inside the mold, making it difficult to uniformly coat the curved mold surface—easily causing material shortage on concave surfaces and accumulation on convex surfaces. Meanwhile, fibers also struggle to maintain ideal uniform distribution on curved surfaces. Qinglong optimizes the thixotropy of the slurry by adjusting admixtures (such as plasticizers and viscosity modifiers), so that it becomes thinner and flows easily under shear force (such as during vibration), and thickens to hold its shape at rest, thereby extending the forming limits.

The Choice of Forming Process Determines the Limit Radius

Different forming processes suit different curvatures: 1) Slurry flow method/vibration casting method: suitable for components with large curvature radii (usually >1.5m). 2) Spraying method: this is the main process for producing small-radius single-curved panels. Fiber-reinforced mortar is sprayed onto the mold by a robotic arm, conforming well to complex curved surfaces. Qinglong's robotic spraying process, with programmatically controlled paths and output volume, is the key technology for achieving small-radius curved surfaces. 3) Press forming: can be considered for specific small-curvature components produced in very large quantities, but mold costs are high.

Strong Correlation Between Panel Thickness and Curvature Radius (Thickness-to-Radius Ratio)

This is a key geometric relationship. The larger the ratio (t/R) of panel thickness (t) to curvature radius (R), the more difficult forming and demolding become, and the higher the internal stress. Typically, to ensure quality and yield, t/R should be less than 1/20. That is, for a 20mm-thick panel, the minimum stable radius is about 400mm; for a 15mm-thick panel, a 300mm radius can be attempted. However, this is only a theoretical reference; in practice, material shrinkage and mold release angles must also be considered.

Mold Precision and Demolding Technology

Small-radius curved molds themselves must have extremely high surface profile precision and finish, usually requiring five-axis CNC machining. Demolding is another major challenge—an excessively small radius may cause the component to "lock onto the mold" or damage the component's edges during demolding. Qinglong designs dedicated demolding systems for small-radius molds (such as pneumatic ejector pins and segmented molds) and uses high-performance release agents to ensure perfect demolding of components.

Therefore, when inquiring about the minimum curvature radius, conditions such as panel thickness, surface requirements, and production quantity must be specified simultaneously. Qinglong Group's technical team can conduct feasibility assessments in the early stages of a project and verify through sample production, finding the optimal solution between artistic creativity and engineering implementation.