What Is the Mold Precision Requirement for Producing UHPC Doubly Curved Panels? Millimeter-Level Precision Assurance and Free-Form Surface Realization Technology

Mould precision for UHPC double-curved panels is the cornerstone that determines whether they can accurately present complex spatial forms and achieve perfect jointing. As a group with 28 years of project experience in the UHPC field, Qinglong Group, drawing on landmark projects such as the "Chinese Red Lantern" of the Wuhan Hanxiu Theatre and the free-form curved surfaces of the Shanghai Astronomy Museum, has established stringent mould precision standards: free-form surface profile error ≤±1mm, 3D coordinate deviation of key positioning points ≤±0.5mm, and mould surface roughness Ra≤0.8μm. This level of precision far exceeds that of traditional concrete components and is the primary prerequisite for achieving visual unity and structural tightness in high-difficulty double-curved building skins.

The high precision of double-curved moulds stems from advanced digital design and manufacturing technology. In the early stage of a project, we use 3D laser scanning to obtain point cloud data of the physical model, or perform parametric modelling directly in a Rhino+Grasshopper environment to generate precise NURBS surface models. Subsequently, five-axis CNC machines precisely machine the mould substrate materials (such as high-density tooling board, aerospace aluminium plate, or resin composites). Taking the double-curved ribbon components we produced for an art centre as an example, the mould surface was defined by hundreds of thousands of toolpath points, and during machining the spindle speed, feed rate, and toolpath spacing were all precisely controlled, ensuring a profile accuracy of ±0.3mm. For extra-large double-curved moulds, we adopt a process of segmented machining followed by high-precision assembly; at the mould fabrication stage, all joints are secured through pre-embedded positioning pins and CNC edge milling, ensuring that overall error does not propagate after assembly.

Beyond machining precision, mould stability and surface treatment are equally critical. Considering the low water-binder ratio and high fluidity of UHPC, moulds must offer excellent sealing, sufficient rigidity, and extremely low surface water absorption. We typically polish the mould surface multiple times and spray a high-performance epoxy resin release agent to create a mirror-smooth interface. In a marine-themed venue project in Hainan, this treatment not only ensured that the surface of the UHPC panels after demoulding was as smooth as glaze, perfectly replicating the design texture, but also reduced demoulding resistance by 40%, effectively preventing edge chipping or micro-cracks caused by mould adhesion.

The value of mould precision is ultimately reflected in the tight, seamless fit of on-site installation. Double-curved panels produced by high-precision moulds feature highly consistent edge geometry and pre-embedded connector positions, making on-site installation as precise and efficient as "building block" assembly. Through a closed-loop quality control system spanning digital design, CNC machining, and 3D scanning verification, Qinglong Group ensures that every double-curved panel is a precise materialized representation of the design intent, providing architects with solid technical support to realize their bold and imaginative creativity.