Repairing scratches on the surface of cleanroom panels requires a tiered approach based on the depth of the scratch, ensuring that the repaired surface remains flat, sterile, and compliant with cleanroom environment requirements.
Scratch Classification and Corresponding Repair Methods
Table
Scratch Type | Depth Characteristics | Repair Method
Minor Scratches | ≤0.1 mm; no obvious indentation | Dry sanding with 800-grit or finer sandpaper → Wet sanding with 2000-grit sandpaper (adding defoamer) → Wipe with anhydrous ethanol
Moderate Scratches | 0.1 mm – 0.3 mm; slight tactile unevenness | Sand into a U-shaped groove using 320-grit sandpaper (groove width = 3x depth) → Blow away dust/debris → Apply epoxy putty in two layers to fill the groove
Severe Scratches | >0.3 mm; compromises structural integrity | Cut a V-shaped bevel (45° angle) using an angle grinder → Apply fiberglass cloth for reinforcement → Apply putty until flush with the surface
Coating Repair and Surface Treatment
Putty Sanding
Coarse Sanding:Sand in a crosshatch pattern using 320-grit sandpaper to avoid linear grooves; use a straightedge to verify flatness (error ≤0.1 mm per 2 meters).
Fine Sanding: Sand with 800-grit sandpaper until the transition is smooth.
Refinishing (Spray Coating)
Primer: Apply one coat of color-matched matte fluorocarbon primer (mixing ratio: 5:1:0.5).
Topcoat: Apply two coats of acrylic polyurethane topcoat or eco-friendly water-based paint, ensuring the paint film is uniform and free of missed spots.
Environmental Control
Temperature: 18–28°C; Humidity: ≤65% RH.
Cleanliness:≥ISO Class 8; use FFU (Fan Filter Unit) purification units within the work area to maintain laminar flow.
Important Considerations
Coating application must be completed within 12 hours of the repair to prevent the substrate from absorbing moisture or becoming contaminated.
Clean using lint-free cloths based on the "one wipe, one change" principle; for critical areas, employ the "grid" (or "well-pattern") wiping method.
Strictly prohibit the use of acid- or alkali-based cleaning agents to avoid surface corrosion.