Why Free-Form GRC Panels Cannot Use Traditional Wood Molds: An Analysis of the Limitations and Challenges of Traditional Wood Molds in Forming Special-Shaped Components

When architectural design breaks free from the constraints of straight lines and flat planes, traditional wooden molds become the "Achilles' heel" of forming special-shaped GRC components. As an industry leader with 28 years of deep expertise in the UHPC/GRC/GRG/GRP materials field, Qinglong Group will analyze, from three dimensions—material properties, process precision, and cost control—why the forming of curved GRC panels must bid farewell to the era of wooden molds.

As modern architectural aesthetics upgrade toward "fluidity" and "sculptural quality," complex forms such as the double-curved curtain walls of grand theaters, the special-shaped sunshades of commercial complexes, and the artistic reliefs of museums are increasingly becoming design mainstream. As a core application scenario of glass fiber reinforced concrete (GRC), these free-form curved components pose unprecedented challenges to forming molds. However, traditional wooden molds, in use for decades, frequently "fall short" when facing three-dimensional special-shaped structures, and their limitations have become a key bottleneck constraining the aesthetic expressiveness of GRC materials.

### 1. The "Wooden Mold Dilemma" of Curved GRC Panel Forming: Limitations Seen from the Nature of the Material

There is a fundamental contradiction between the physical properties of traditional wooden molds and the process requirements of GRC materials. The forming of GRC components involves multiple processes such as material pouring, curing, and demolding. Wooden molds are easily corroded by alkaline substances in cement slurry, causing bulges and cracks on the mold surface that directly affect the surface precision of components. More critically, the coefficient of thermal expansion and contraction of wood differs significantly from that of GRC materials, readily triggering a chain reaction of "mold deformation—component cracking" during curing. A landmark project once used wooden molds to produce double-curved GRC cladding panels with a radius of 3 meters; mold shrinkage caused by changes in wood moisture content resulted in a final curved surface error of 8mm, far exceeding the 3mm precision requirement permitted by the design.

Qinglong Group discovered as early as the detailed design stage that, for complex curved surfaces with a radius of curvature ≤500mm, the splicing gaps of wooden molds leave "joint marks" on the GRC surface that are difficult to eliminate. Qinglong's self-developed composite material molds, by contrast, achieve a surface smoothness of Ra≤3.2μm through integrated pouring technology, perfectly reproducing the streamlined aesthetics of the design drawings.

### 2. The "Precision Gap" of Special-Shaped Components: The Collision of Traditional Craftsmanship and Modern Demands

The "boundless imagination" of architectural design demands "millimeter-level rigor" in mold manufacturing. Traditional wooden molds rely on manual lofting and splicing, making it difficult to translate the complex curved-surface data of parametric design. Take the double-curved honeycomb GRC curtain wall of a convention and exhibition center as an example: a single component contains 12 transition surfaces of different curvatures, and the wooden mold required 37 splicing units, with cumulative errors reaching over 15mm. By contrast, Qinglong's integrated 3D printing + CNC machining mold technology can directly convert BIM models into physical molds, controlling forming precision within ±0.5mm while shortening the production cycle by 40% compared with wooden molds.

For special-shaped GRC components such as openwork reliefs and variable-thickness forms, the "subtractive manufacturing" logic of wooden molds is simply incapable. Through improvements to GRP (glass-reinforced thermosetting plastic) molds, Qinglong has achieved the forming of ultra-thin GRC components with a minimum wall thickness of 5mm, whereas traditional wooden molds, constrained by material strength, require a minimum wall thickness of more than 15mm, adding self-weight and wasting material.

### 3. The Whole-Life-Cycle "Cost Trap": The Hidden Price of Wooden Molds

Most project owners focus only on the initial procurement cost of wooden molds while overlooking their hidden expenses over the full life cycle. The fragility of wood means molds usually last no more than 5 reuse cycles, whereas Qinglong's composite material molds can be reused more than 50 times; based on an annual output of 600,000 square meters of GRC components, mold costs can be reduced by 60%. More importantly, the low precision of wooden molds requires extensive on-site grinding and adjustment during later installation. One cultural tourism project incurred an additional construction cost of 300,000 RMB for this reason, whereas adopting Qinglong's prefabricated high-precision GRC components improved installation efficiency by 50% and achieved "zero on-site processing."

As a national high-tech enterprise that participated in formulating the Technical Standard for Building Application of Glass Fiber Reinforced Cement (GRC) (JGJ/T423-2018), Qinglong Group deeply understands that innovation in mold technology is the key to unlocking the aesthetic potential of GRC materials. From parametric mold modeling in the detailed design stage, to the application of composite material molds in production and manufacturing, to three-dimensional laser positioning in construction and installation, Qinglong has built a full-chain solution for special-shaped GRC components. To date, Qinglong has provided customized curved GRC panel services for 500+ landmark projects at home and abroad, among which the Dongguan Women and Children's Activity Center project won the Silver Award of the first GRC Building Engineering Innovation Award for its double-curved GRC curtain wall system.

When architecture becomes "frozen art," the mold is the "carving knife" of that sculptural art. Bidding farewell to traditional wooden molds is not merely a simple technological iteration, but the industry's leap from "experience-dependence" to "digital precision." Qinglong Group will continue its mission of "creating beautiful architecture," drawing on 28 years of full-chain experience to provide designers with broader material possibilities for turning their creative ideas into reality, making every curved surface a crowning touch of architectural aesthetics.