Analysis of Mold Cost Proportion in Total Cost of Hollowed-Out UHPC Shapes and Discussion of Influencing Factors

In balancing the artistic expression of building skins with engineering economics, mold cost is the key lever that turns hollowed-out UHPC designs from drawings into reality.

With the widespread application of ultra-high performance concrete (UHPC) in high-end settings such as landmark buildings and cultural venues, cost control of complex shapes like hollowed-out and irregular forms has become a core issue of shared concern for owners and designers. As an industry player with 28 years of deep expertise in the UHPC/GRC/GRG/GRP materials field, Qinglong Group has found through full-chain experience that molds, as the core vehicle for realizing shapes, carry a cost share that directly affects project return on investment. This article provides an in-depth analysis of the mold cost logic of hollowed-out UHPC designs from two aspects—proportion composition and influencing factors—offering the industry a reference that combines technical depth with economic considerations.

### I. Proportion Characteristics of Mold Costs for Hollowed-Out UHPC Designs

In conventional UHPC component production, mold costs typically account for 15%-25% of the total project cost, but when complex texture designs such as hollowed-out or embossed patterns are involved, this proportion can climb to 30%-45%. Take a cultural center hollowed-out curtain wall project as an example: the mold investment for its parametric honeycomb hollowed-out design reached 38%, significantly higher than the 20% benchmark for flat panels. This difference mainly stems from the special requirements of hollowed-out structures for mold precision, material strength, and processing techniques—processes such as high-precision CNC engraving, irregular steel mold welding, and surface texture forming all drive up costs. In the translucent concrete project at Century Plaza on Nanjing East Road, Qinglong Group controlled the mold cost share of the hollowed-out design at 32% through modular mold design, 12% lower than traditional processes, confirming the role of technical optimization in cost regulation.

### II. Four Core Factors Determining Mold Costs

**1. Design Complexity and Precision Requirements** The density of hollowed-out patterns, minimum aperture, and surface curvature directly determine the mold structure. When the hollowing rate exceeds 40% or the aperture is smaller than 50mm, the mold requires a steel-aluminum composite structure to avoid deformation, increasing material costs by more than 30%. Qinglong's detailed design team used Rhino parametric modeling to reduce the number of mold blocks for a theater's hollowed-out ceiling by 27% and cut machining hours by 40%, effectively balancing artistic expression with economics.

**2. Mold Materials and Reuse Count** Wooden molds are low in cost but can only be reused 3-5 times, making them suitable for small-batch customization; steel molds require high initial investment (about 5 times that of wooden molds) but can be reused more than 50 times, resulting in lower amortized costs in the long run. In a commercial complex project in Foshan, Qinglong used Q345B steel to make molds for hollowed-out UHPC sunshade panels and, through surface chrome plating, raised the reuse count to 80 times, reducing the per-use cost by 62%.

**3. Production Scale and Process Selection** Batch production can significantly dilute mold amortization costs. When the number of components exceeds 100, mold costs with standardized modular design can be reduced by 25%-35%. Qinglong's Guangxi production base achieved rapid switching between different hollowed-out patterns through a "universal mold frame + replaceable shape inserts" model. In a municipal project in Guangzhou, the mold development cycle for 5 types of irregular hollowed-out components was compressed to 15 days, with costs reduced by 22%.

**4. Technical Integration Capability** Full-chain service capability directly affects the effectiveness of mold cost control. As a national high-tech enterprise integrating detailed design, manufacturing, and construction installation, Qinglong achieved digital collaboration across design-production-installation through BIM technology. In the Dongguan Women and Children's Activity Center project, it preemptively avoided mold interference issues at 8 hollowed-out design locations, cutting rework costs by approximately RMB 180,000.

### III. Practical Paths to Balancing Art and Cost

Mold cost control for hollowed-out UHPC designs is essentially a combination of technical innovation and engineering experience. Project parties are advised to involve material suppliers from the design stage and optimize costs through the following strategies: first, adopt "structure-driven shaping" instead of "decoration-driven shaping" to simplify the mold structure while ensuring the hollowed-out effect; second, prioritize reusable mold materials and plan production batches reasonably according to project scale; third, leverage parametric design and modular construction to improve mold utilization efficiency. With 58 patented technologies and experience participating in the formulation of the "General Technical Conditions for Non-Load-Bearing Components of Ultra-High Performance Concrete (UHPC)" standard, Qinglong Group has provided hollowed-out UHPC solutions for more than 200 projects, confirming the value of professional services in cost optimization.

Today, as architectural aesthetics become increasingly diversified, hollowed-out UHPC designs are becoming an important vehicle for showcasing project individuality. Scientific management of mold costs requires both the technical accumulation of material suppliers and collaborative innovation among all parties across the industry chain. Qinglong Group will continue to uphold its mission of "creating beautiful architecture," and through technical iteration and accumulated experience, bring more artistic UHPC designs to life while keeping costs under control, promoting the high-quality development of the new architectural decorative materials industry.