What Are the Parting Principles for Complex GRC Shapes? Manufacturability and Qinglong Group's Mold Design Wisdom

Parting design for complex GRC forms is the critical link connecting creativity and manufacturing, with the core principle of balancing the fourfold requirements of "aesthetic integrity, manufacturability, economy, and demoldability." From 28 years of projects, Qinglong Group has distilled the "golden rules" of parting: parting lines should be placed in visually weak areas or at natural transitions; the integrity of large surfaces should be prioritized to reduce the number of blocks; modular design should be adopted to increase mold reuse rates; and the draft angle should be ≥1° to ensure smooth demolding. In the "Dongguan Grass Weaving" facade project at the Dongguan Women and Children's Activity Center, we used parametric algorithms to optimize complex curved surfaces into 2,872 panels, reducing mold types from an estimated 300 sets to 12 standard modules, cutting costs by 40%, while visually concealing the joints entirely. Scientific parting is the prerequisite for realizing art.

Visual-Analysis-Based Parting Line Placement

The primary principle for parting lines is "concealment"—placing them in visually insensitive areas such as internal corners, within decorative moldings, or at material transitions. Using sightline analysis software, we simulate how the human eye perceives at different distances and angles, prioritizing joints in visual blind spots or shadow zones. For double-curved surfaces, parting lines should follow directions of minimal curvature change (approximating geodesic lines) to reduce the abruptness of seams.

Manufacturability-Oriented Modular Design

Parting must consider the feasibility of production processes. The dimensions of a single module are limited by equipment processing capacity (such as CNC table size), demolding difficulty, and transportation conditions. Through modular design, we break complex forms into a limited number of standard units, achieving rich effects through arrangement and combination. In the Nanning New Media Center project, we optimized free-form surfaces into 5 standard panels, assembling the entire facade through rotation and mirroring, greatly reducing mold costs.

Demolding Feasibility as a Hard Constraint in Parting Design

Parting design must ensure that every module can be smoothly released from the mold without "undercut" structures. For deep cavities or negative-angle forms, detachable loose-block molds or flexible silicone molds are required. The draft angle is typically no less than 1–3 degrees, adjusted according to form depth. We use 3D software for demolding interference checks, identifying and resolving potential issues in advance.

Optimal Balance of Economy and Efficiency

The number of partings directly affects mold costs and production efficiency. While meeting form and structural requirements, we strive to cover the largest area with the fewest module types. Using parametric design tools, we automatically generate multiple parting schemes and run cost simulations to select the optimal solution for clients. For example, in an art wall project in Shenzhen, optimization reduced the number of blocks from 200 to 80, shortening the schedule by 35%.

Excellent parting design is a comprehensive embodiment of artistic perception, structural knowledge, craftsmanship experience, and economic thinking. With this cross-disciplinary integration capability, Qinglong Group's detailed design team turns boundless creative ideas into tangible, touchable reality.