Forming Process Flow for One-Piece Toilets

During the product development modeling phase, designers utilize specialized software to shape the product's exterior and construct a three-dimensional appearance model. They meticulously refine every curve and surface to ensure compliance with aesthetic and ergonomic principles. Subsequently, the model is transferred to engineering software for in-depth development. The resulting digital prototype serves not only as an exact blueprint of the product's appearance but also as a comprehensive preview of its internal functionality and manufacturability, laying a solid foundation for subsequent mold design and production processes.

Raw materials form the foundation of ceramic product quality. Multiple base materials—kaolin, clay, quartz, feldspar, and others—must be precisely weighed according to scientific ratios. Subsequently, these materials are combined with water and fed into a ball mill. Through continuous rolling and grinding, the components achieve thorough mixing and refinement, ultimately forming a uniform, fine-textured slurry with excellent fluidity.

The ground slurry must undergo rigorous iron removal and purification. This process thoroughly removes iron impurities mixed within the slurry. This step is critical because even minute iron residue will undergo oxidation during subsequent high-temperature firing, forming black ferric oxide spots. These spots not only severely compromise the product's visual integrity but also directly result in substandard goods. Therefore, the iron removal process is a key step in ensuring the superior quality and grade of the glaze finish.

Slip casting is a core process in sanitaryware manufacturing. Its principle involves utilizing the microporous characteristics of specially designed plaster molds to achieve green body forming through physical adsorption.

The specific process is as follows: Prepared uniform slip is injected into hollow plaster molds. The plaster mold acts as an efficient moisture exchanger, continuously absorbing water from the slurry. As water permeates through the mold walls and drains out, solid ceramic particles gradually deposit onto the inner surface of the mold, forming a layer of uniform thickness and dense clay body. Once the clay body reaches the predetermined thickness, excess slurry is drained from the mold. After undergoing appropriate drying and shrinkage, the mold can be opened to yield structurally complete sanitaryware greenware.

1. Trimming and Bonding

After the raw clay undergoes short-term natural air-drying to achieve initial setting strength, artisans meticulously refine its surface, removing mold lines and burrs to ensure a smooth, uniform form. Subsequently, using a specially formulated bonding slurry, the separate components—such as the toilet tank and base—are precisely joined into a single unit. This step is critically important, demanding exceptional skill from the craftsman to ensure the seams are secure and leave no visible traces.

2. Controlled Drying

The fully shaped and bonded clay bodies are transferred to a controlled-environment drying kiln for gradual and uniform dehydration. The drying regimen typically follows a curve of “low temperature and high humidity at the start, gradually increasing temperature while reducing humidity.” This gentle drying strategy aims to control moisture migration and evaporation from the interior to the exterior slowly and uniformly. It effectively prevents cracking or deformation of the green body caused by stress resulting from rapid surface drying and residual moisture within. This process is a critical safeguard ensuring the integrity of the green body as it enters subsequent stages and determines the final yield rate.

Glazing is a critical process that imparts surface smoothness, aesthetic appeal, and easy-to-clean functionality to sanitaryware products. During this stage, the fully dried surface of the ceramic body is uniformly coated with a layer of specially formulated glaze.

In modern large-scale production, robotic automated glazing systems are widely adopted. Through pre-programmed motion trajectories, robotic arms precisely control spray gun angles, distances, and glaze flow rates, achieving uniform coating without blind spots on complex products like toilets. This automation not only ensures consistent glaze thickness and significantly boosts production efficiency but also markedly reduces the unpredictability of manual operations.

Following high-temperature firing, the glaze melts and transforms into a dense, hard, and smooth vitreous layer. This glaze surface forms the physical foundation for core functional properties of sanitaryware—including stain resistance, impermeability, and wear resistance—directly determining the final product's quality grade and user experience.