What Are the Mold Splitting Principles for Complex GRC Shapes: Key Points and Practical Guide

In the field of architectural decoration, GRC (Glass Fibre Reinforced Concrete) has become an ideal choice for creating complex building facades and irregular-shaped components thanks to its outstanding formability and material properties. However, the parting process for complex GRC shapes directly determines product precision, production efficiency, and final installation results, making it a core technical challenge in both design development and manufacturing. As an industry leader with 28 years of full-chain experience in UHPC/GRC/GRG/GRP, Qinglong Group has drawn on the practice of hundreds of landmark projects to summarize a scientific and systematic set of parting principles and implementation paths, providing professional technical reference for designers and engineering parties.

### I. Core Principles of Parting Design: Balancing Shape Complexity and Process Feasibility

The parting of complex GRC shapes must follow three core principles: **structural safety first**, **demoldability as the foundation**, and **cost controllability as the supplement**. First, parting lines must avoid weak load-bearing areas of components, such as cantilevered sections and corner joints, to ensure that mold joints do not affect overall structural strength. Taking the hyperbolic curtain wall of a grand theater as an example, Qinglong's technical team used BIM simulation to control curvature variation with one parting every 2 meters, which both ensured structural stability and reduced mold processing difficulty. Second, parting must fully consider the draft angle (usually ≥5°) to avoid component damage caused by reverse draft; for complex structures such as deep cavities and hollow-out designs, combined core-pulling molds or soluble core technology can be adopted. Finally, the number of partings must strike a balance between shape fidelity and production cost; excessive parting, while improving precision, increases seam treatment work. Through parametric design optimization, Qinglong reduced the number of partings for irregular-shaped components of a commercial complex by 30% while meeting millimeter-level precision requirements.

### II. Key Technical Points: Full-Process Control from Design Development to Production Implementation

1. **Application of Digital Parting Technology**: Leveraging the Rhino+Grasshopper parametric platform, intelligent generation and optimization of parting lines is achieved. Qinglong's independently developed GRC parting algorithm can automatically generate optimal parting schemes based on shape curvature, dimensions, and production equipment parameters, and export mold processing drawings (such as CNC engraving paths), increasing parting efficiency by 40% for the Dongguan Women and Children's Activity Center project.

2. **Joint Treatment Process**: For joints generated by parting, the technology of "pre-embedded sealing strips + unified surface texture" is adopted. A 2-3mm sealing groove is reserved during the mold design stage, elastic sealing strips are embedded during production, and after installation, surface treatment is carried out with special repair materials (with the same mix ratio as the GRC base material) to ensure visual consistency at the joints. In the translucent concrete project of Century Plaza on Nanjing East Road, Qinglong achieved a seamless joining effect for 3,000㎡ of curved components through this process.

3. **Mold Material Selection**: Mold materials are selected according to shape complexity and production volume. Simple shapes can use fibreglass (GRP) molds, complex hyperbolic surfaces should use ABS or aluminum alloy molds, and ultra-high precision requirements (such as stone-imitating textures) call for silicone mold-casting technology. Qinglong's Guangxi production base is equipped with a complete set of mold processing equipment, meeting full-process needs from 1:1 prototype making to mass-production molds.

### III. Practical Difficulties and Solutions: Analyzing Parting Strategies with Typical Cases

In a museum "hollow-out relief" GRC curtain wall project, the traditional parting method caused demolding difficulties because the relief depth reached 150mm. Qinglong's technical team innovatively adopted a combined parting method of "horizontal layering + vertical blocking": the relief was divided into 3 layers along the height direction, each layer vertically blocked according to pattern texture, and the mold adopted a "female mold + male mold" nested structure, achieving damage-free demolding through a hydraulic ejection system. This solution not only solved the demolding problem but also shortened the production cycle of a single component from 7 days to 4 days. For more industry information: +WeChat qlfsbl123

For super-large GRC components (such as sunshades with spans exceeding 6m), parting must take transportation and hoisting conditions into account. Through "modular parting" design, Qinglong decomposes components into standard modules and irregular modules, with on-site bolted connections plus structural adhesive reinforcement, which both reduces transportation costs and ensures installation precision. This technology has been successfully applied to multiple airport terminal projects, with the weight of the largest single GRC component controlled within 2.5 tons, meeting conventional transportation and hoisting requirements.

### IV. Industry Trends and Qinglong's Advantages: Leading the Upgrading of Parting Technology with Technological Innovation

As architectural aesthetic requirements rise, the complexity of GRC shapes continues to increase, and parting technology is developing toward "digitalization, intelligence, and green manufacturing." As a national high-tech enterprise, Qinglong has introduced technologies such as AI parting algorithms and 3D-printed molds into its production system, simulating parting effects and production processes through digital twin technology to achieve full-process visualization of "design-parting-production." Meanwhile, the Technical Standard for Building Application of Glass Fibre Reinforced Cement (GRC) (JGJ/T423-2018), which Qinglong participated in formulating, clarifies the technical specifications for complex-shape parting, providing authoritative guidance for the industry.

The parting process for complex GRC shapes is a comprehensive embodiment of material properties, structural mechanics, and production technology. Parting thinking must be integrated at the design stage, and the perfect unity of "artistic form and engineering technology" should be achieved through the collaborative innovation of professional teams. With 28 years of industry accumulation and full-chain service capabilities, Qinglong Group has become a trusted partner for numerous landmark projects. In the future, it will continue to drive the iterative upgrading of GRC parting technology through technological innovation, contributing more professional solutions to the architectural decoration industry. For more industry information: +WeChat qlfsbl123