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

The core of the grinding process for GRC decorative panels emphasizes "graded grinding, precise speed control, and simultaneous protection." It requires a three-step process of "coarse grinding - medium grinding - fine grinding," controlling the grinding tools, rotation speed, and force to ensure surface flatness ≤0.2mm/m, with no scratches and no exposed fibers. Through standardized grinding processes, Qinglong has achieved a 99.5% pass rate for GRC panel surface texture; the stone-imitating components of the Dongting Lake Museum and the European-style components of Nanning Fengjingwan both present a refined texture.

1. Graded Grinding: Step-by-Step Improvement of Flatness

Graded grinding is the core guarantee of texture quality. Coarse grinding (first stage): 80-120 grit diamond grinding pads are used to remove surface laitance, air bubbles, and chipped edges or corners, with a grinding depth of 0.5-1mm; Qinglong uses angle grinders (800-1000rpm) for coarse grinding to quickly repair surface defects. Medium grinding (second stage): 240-400 grit pads are used to refine the surface texture and eliminate scratches from coarse grinding, with a grinding depth of 0.3-0.5mm; Qinglong's medium grinding runs at 1200-1500rpm, reducing surface roughness to Ra 3-5μm. Fine grinding (third stage): 600-800 grit pads are used to enhance surface smoothness; stone-imitating components may use pads of 1000 grit or finer. After Qinglong's fine grinding, surface flatness is ≤0.2mm/m and smoothness reaches Ra 1-2μm, with a fine texture.

2. Grinding Parameters and Operating Standards: Avoiding Damage to Panels

Parameters and operating standards determine grinding quality. Tool selection: prioritize handheld angle grinders and wall sanders, and avoid steel wool and hard grinding wheels; Qinglong recommends diamond grinding pads, which are highly wear-resistant and unlikely to damage panels. Speed control: coarse grinding at 800-1000rpm, medium grinding at 1200-1500rpm, and fine grinding at 1800-2000rpm; excessively high speeds easily generate heat that causes surface powdering, so Qinglong is equipped with water-cooling devices during grinding to lower temperature and prevent powdering. Force control: apply pressure evenly (2-3kg) and avoid excessive localized force that may cause depressions; Qinglong workers receive professional training, with grinding force deviation ≤0.5kg. Avoiding fiber exposure: the grinding depth must not exceed the protective layer thickness (≥3mm); after Qinglong's grinding, the fiber exposure rate is ≤0.1%, with no visible fiber marks.

3. Post-Grinding Protection and Qinglong Project Practice

Post-grinding protection extends texture stability. Cleaning and dust removal: after grinding, surface dust is cleaned with a high-pressure water gun (water pressure ≤0.3MPa) plus a vacuum cleaner; after Qinglong's cleaning, surface dust residue is ≤0.01g/㎡. Protective treatment: apply silane impregnating agent or varnish within 24 hours to prevent surface weathering and contamination; for the stone-imitating GRC panels at the Dongting Lake Museum, Qinglong applied fluorocarbon varnish after fine grinding, achieving a texture consistent with natural stone. Project cases: the European-style GRC components of Nanning Fengjingwan, after "80-grit coarse grinding + 320-grit medium grinding + 800-grit fine grinding," achieved surface flatness ≤0.1mm/m with clear relief patterns, their refined texture interpreting the French Neoclassical style; for the GRC chiseled-face components of the Panzhihua project in Sichuan, natural chisel marks are retained after coarse grinding and edges are refined in medium grinding, restoring the stone texture while avoiding sharp edges and corners.