What Are the Key Points of the Sanding Process for GRC Decorative Panels?

Surface grinding of GRC decorative panels is a key process for enhancing aesthetics and texture, requiring differentiated techniques based on product type and application location. Qinglong Group has developed a standardized workflow of three processes—rough grinding, fine grinding, and polishing—to ensure surface quality meets design requirements.

Rough grinding removes visible defects. Using 60-80 grit grinding wheels, demolding marks and joint misalignments are eliminated. In the Wuhan Han Show Theatre project, Qinglong Group applied manual grinding to the carved panels, focusing on the raised and recessed areas of the reliefs to ensure smooth lines. Grinding depth was kept within 0.5mm to avoid damaging the reinforcement layer. After rough grinding, surface flatness met the 3mm/2m standard.

Fine grinding improves surface refinement. Switching to 120-240 grit grinding wheels for a second pass removes rough grinding marks. In the Shenzhen Yirui Biotechnology Building project, we adopted robotic arm automated grinding with pressure controlled at 0.2-0.3MPa and a movement speed of 3-5m/min to ensure grinding uniformity. After fine grinding, surface finish reached Ra6.3μm, laying the foundation for subsequent treatment.

Polishing achieves the desired texture. The polishing process is selected according to the design effect: glossy finishes use 800-1000 grit resin pads to achieve a mirror effect; matte finishes use 400 grit pads combined with wool wheels to create uniform diffuse reflection. In the Shanghai Century Plaza project, Qinglong Group controlled the polishing parameters to achieve a light transmittance of 15%-20% for translucent UHPC panels, perfectly presenting the design effect.