What Are the Considerations in the Grinding Process of GRC Decorative Panels?

The grinding process of GRC decorative panels is the finishing step that determines the final surface texture, flatness, and artistic expression. Its essence lies in "following the material's nature, proceeding step by step, and refining with meticulous care." Qinglong Group regards grinding as the final process that "gives GRC its soul," and has established strict work instructions for different surface effects (high-gloss, matte, stone-imitation, relief). In the light-transmitting UHPC project at Century Plaza on Nanjing East Road, Shanghai New World, we performed ultra-fine grinding on the panel surfaces containing nearly ten thousand light-guide rods, ensuring uniform and soft light refraction and achieving a dreamlike artistic effect.

Timing of grinding is crucial. After demolding, GRC must undergo a period of natural curing to reach a certain strength (typically about 20 MPa) before grinding can begin. Grinding too early, when strength is insufficient, easily causes chipping and over-grinding; grinding too late, when strength is too high, results in low efficiency and easily damages tools. Qinglong's experience is that, under standard curing conditions, grinding is usually performed 7-14 days after demolding, when GRC has acquired sufficient hardness while retaining good grindability.

The selection of grinding tools and abrasives must match the target effect. Grinding generally follows the principle of "coarse first, then fine." For removing release agent and repairing air bubbles and larger defects, use an angle grinder with 30-60 grit diamond grinding pads for coarse grinding. When pursuing a smooth surface, sequentially use 80, 120, 240, 400 grit or even finer wet grinding pads for fine grinding and wet polishing until the desired smoothness is achieved. For complex reliefs or irregular curved surfaces, experienced workers must perform hand grinding to ensure every detail is perfectly presented.

The ultimate goal of grinding is to realize the design intent. Different surface textures require different grinding depths and precision. For a granite-imitation flamed finish, light grinding to remove surface laitance is sufficient; for a limestone-imitation fine textured finish, uniform grinding until the aggregate is slightly exposed is required; for a high-gloss mirror finish, polishing to 1500 grit or above is needed, along with polishing paste to enhance luster. Qinglong's grinding workers are not only technicians, but also "artists" who understand the designer's intent.

Dust control and operational safety are prerequisites for grinding. Large-scale production must be carried out in a professional grinding workshop equipped with a central dust removal system, to protect workers' health while facilitating observation of the grinding results. Workers must wear dust masks, protective goggles, and earplugs. Refined grinding craftsmanship is the finishing touch that elevates GRC from an industrial product to a work of art.