What Are the Common Mold Materials for UHPC Components, and What Are Their Advantages?

In the precision manufacturing system of UHPC components, the choice of mold material directly determines the product's final appearance precision, production efficiency, and economics. As the Qinglong Group with 28 years of UHPC R&D and manufacturing experience, we have systematically categorized commonly used mold materials into four major types—steel molds, resin molds (GRP molds), substitute-wood molds, and silicone molds—based on practices from hundreds of large-scale projects, and make scientific selections according to component shape complexity, dimensional precision, surface texture requirements, and production volume.

Steel molds are the first choice for ultra-high precision and long service life. Machined by CNC from Q235 or No. 45 steel, steel molds offer the greatest advantages of extremely high dimensional stability and exceptionally long service life. In curtain wall projects with stringent requirements on panel joint flatness, such as the Shenzhen Yirui Biotechnology Building, Qinglong extensively uses steel molds to produce standardized panels; they can be reused over a thousand times while ensuring millimeter-level dimensional accuracy across batches. Steel mold surfaces can be polished, sandblasted, or etched to achieve mirror, matte, or specific textured effects. However, they involve longer mold-making lead times and higher initial investment, making them more suitable for components produced in large volumes or for long-term repeated production.

Resin molds (GRP molds) achieve the best balance between complex shapes and cost-effectiveness. Based on epoxy or vinyl ester resin and reinforced with glass fibers, resin molds offer good toughness and plasticity, making them well suited for molds of double-curved surfaces, reliefs, and irregularly shaped components. In producing the complex red curtain wall panels for the Wuhan Han Show Theatre, Qinglong made extensive use of high-strength resin molds, which accurately replicate complex curved forms while being lightweight and easy to handle in production. Resin molds are quick to produce, moderately priced, and typically last 50-100 uses, making them the ideal choice for medium-volume complex components.

Substitute-wood molds and silicone molds are suitable for special artistic effects and small-batch production. Substitute wood (such as high-density foam board) is easy to CNC-carve and suitable for making molds for large or one-off artworks with complex shapes but not extremely demanding surface texture requirements, such as the large sculptures at the Shanghai Astronomy Museum. Silicone molds feature excellent flexibility and replication precision, perfectly reproducing extremely fine textures (such as wood grain and stone pores), and are commonly used for UHPC components with special surface effects, such as the wood-grain translucent UHPC panels at Shanghai Century Plaza. Qinglong flexibly combines molds of different materials according to each project's artistic requirements and economics to achieve the optimal production results.