Analysis of Common Mold Materials for UHPC Components: Comparison of Characteristics and Application Advantages of Steel Molds, Polyurethane Molds, and More

The choice of mould material directly determines the forming precision, surface texture, and production efficiency of UHPC components. Common materials include steel moulds, polyurethane moulds, GRP (fibreglass) moulds, and wooden moulds, each with its own suitable application scenarios and core advantages. Qinglong, a national high-tech enterprise with 28 years of UHPC production experience, precisely matches mould materials to the requirements of different projects, achieving breakthroughs in both design and quality in projects such as Shanghai New World and the Ouargla Hotel in Algeria.

Steel moulds are the material of choice for large-scale UHPC production, with core advantages of high strength, high precision, and durability. Qinglong manufactures steel moulds from Q235 steel plates machined by CNC, with mould precision error ≤±0.5mm, surface flatness ≤0.3mm/m, and reusability of more than 500 times, suitable for standardized components such as flat panels and lines as well as extra-large components. In the Yangshengtang Pharmaceutical Hangzhou Industrial Park project, UHPC facade panels produced with steel moulds had dimensional deviations controlled within ±1mm, with smooth, fine surfaces requiring no secondary grinding. The high strength of steel moulds withstands the pressure and vibration during UHPC pouring, ensuring component density, making them especially suitable for load-bearing components with high compressive strength requirements. However, steel moulds involve higher manufacturing costs and longer lead times, making them more suitable for mass production or long-term partnership projects.

Polyurethane moulds are ideal for complex-shaped UHPC components, renowned for high fidelity and easy demoulding. Qinglong uses high-density polyurethane material, with moulds made through 3D scanning and CNC engraving, precisely reproducing complex textures such as reliefs and double-curved surfaces, with fidelity ≥95% and surface roughness Ra≤3.2μm, meeting the artistic shaping needs of UHPC components. The UHPC wood-grain translucent panels at Shanghai New World Century Plaza on Nanjing Road feature simulated tree bark textures precisely rendered through polyurethane moulds, and the installation and positioning of 8,000-10,000 light-guide rods per square meter also rely on the high precision of the moulds. Polyurethane moulds have low demoulding resistance, leaving component surfaces free of post-treatment, and shorten mould-making cycles by 30% compared to steel moulds; however, they can be reused only about 50-100 times, making them more suitable for customized, small-batch projects with complex shapes.

GRP (fibreglass) moulds combine light weight with corrosion resistance, suited to producing moderately complex components. Qinglong's GRP moulds are made from a composite of glass fibre and epoxy resin, weighing only one-third of steel moulds of the same size, easy to transport and install, with good water and alkali resistance, suitable for outdoor production scenarios. In the Shenzhen Yirui Biotechnology Building project, L-shaped and U-shaped UHPC components produced with GRP moulds ensured shaping precision while controlling mould costs. The manufacturing cost of GRP moulds falls between steel and wooden moulds, with about 100-200 reuses; their surfaces can be polished, suiting components with moderate surface texture requirements, but their rigidity is slightly lower than that of steel moulds, requiring supporting structures to avoid deformation.

Wooden moulds are suitable for temporary or simply shaped components, with core advantages of low cost and fast mould-making. Qinglong uses high-density plywood treated for water resistance to make wooden moulds, suitable for small-batch production of components such as flat panels and simple lines, with mould-making cycles shortened to 1-3 days. However, wooden moulds have lower precision (error ≤±3mm), can be reused only 5-10 times, are prone to deformation under humidity, and require release agent coating on their surfaces; component surfaces may also need grinding later, making them more suitable for simple projects with tight schedules and limited budgets.

Leveraging the technical strength of its provincial-level R&D center, Qinglong has established a mould material selection system that comprehensively matches the optimal mould based on component shape complexity, production volume, and precision requirements. From the large sculptures of the Shanghai Astronomy Museum (a steel + polyurethane mould combination) to the perforated panels in Algeria (steel moulds), the precise adaptation of mould materials serves as an important guarantee of UHPC quality. For designers and owners, the choice of mould material must balance project requirements and cost budgets. With full-chain service capabilities, Qinglong provides integrated solutions from mould design and fabrication to production, ensuring that every UHPC component achieves a perfect unity of design and quality.