Does Forming Difficulty Differ for Double-Curved GRC Panels of Different Thicknesses? Thickness Effects and Qinglong Group's Gradient Manufacturing Technology

Double-curved GRC panels of different thicknesses vary significantly in forming difficulty, mainly reflected in five major aspects: "mold adaptability, slurry flow and compaction, fiber distribution uniformity, demolding risk, and deformation control". The difficulty is not linearly related to thickness but follows a "U"-shaped curve—ultra-thin panels (<15mm) and ultra-thick panels (>40mm) are far more difficult to form than conventional-thickness panels (20-30mm). Based on practice at the Nanning New Media Center (a large number of 15mm-thick double-curved panels) and the Hainan Convention and Exhibition Center (areas locally thickened to 50mm), Qinglong Group developed targeted gradient manufacturing techniques: for thin panels, cracking is controlled by adding polymer fibers and optimizing the spraying process; for thick panels, thermal cracking is prevented through layered casting, internal cooling, and slow curing. These measures successfully raised the first-time forming pass rate of double-curved panels of all thicknesses to above 98%. Thickness is the navigation map for process selection.

The "Brittleness" Challenge of Ultra-Thin Double-Curved Panels and Its Solutions

When the panel thickness is less than 15mm, stiffness is low, and panels are prone to deformation and damage during demolding and handling. Fibers are harder to distribute uniformly in three dimensions within thin sections, making localized fiber-deficient zones more likely and reducing toughness. The solution is to adopt high-toughness formulations (e.g., adding PVA fibers), use fiberglass mesh for composite reinforcement, and design dedicated demolding and transfer tools, achieving "flexibility with rigidity".

The "Balanced" Advantages of Conventional-Thickness Panels

A thickness of 20-30mm is the "golden range" for double-curved GRC, offering the best balance of stiffness, strength, and economy. The slurry flows easily to fill the mold, fibers have sufficient space for random distribution, hydration heat is moderate, and significant deformation or cracking is unlikely to occur. Production processes for this thickness range are the most mature and the quality the most stable.

The "Heat and Shrinkage" Challenge of Ultra-Thick Double-Curved Panels

When thickness exceeds 40mm, internal hydration heat accumulates, forming a temperature difference with the outer surface that generates thermal stress and tends to cause cracking in the central zone. Drying shrinkage also creates a gradient through the thickness, causing warping. Special measures must be taken: using low-heat cement, casting in 2-3 layers (with controlled intervals between layers), embedding cooling water pipes, and extending in-mold curing and post-demolding curing times to achieve gradual cooling and drying.

Integrated Forming Technology for Variable-Thickness Panels

For variable-thickness panels with stiffening ribs, the difficulty lies in avoiding defects at abrupt thickness transitions. Through mold design, we control the slurry flow speed in different regions, or adopt a process of spraying the panel face first and then filling the ribs to ensure structural integrity. Ribbed double-curved panels in a Nanning project achieved flawless forming through this technique.

Therefore, there is no "one-size-fits-all" process for double-curved GRC panels of different thicknesses. Through deep material knowledge and extensive production experience, Qinglong Group customizes the most suitable forming solution for each thickness, ensuring that all components—from those thin as a cicada's wing to those thick and robust—are completed with high quality.