1. Remove Surface Contaminants
Oil/Grease Removal: Wipe the plate surface with a lint-free cloth soaked in acetone or industrial degreaser-pay extra attention to areas with machining oil residues (from rolling or storage). Rinse with clean water (for water-based degreasers) and dry completely to avoid moisture-induced oxidation.
Dust/Loose Rust Removal: Use a soft-bristled brush or low-pressure air blower to remove surface dust, sand, or loose initial rust. For plates with thick, flaky rust (not mature patina), use a stainless steel wire brush to scrub the surface lightly-avoid heavy grinding that thins the plate unevenly.
Prohibition: Do not use acidic cleaners (e.g., hydrochloric acid) - residual acid will corrode the steel and contaminate the laser cutting system.
2. Protect Mature Patina Layers (If Applicable)
Cover non-cutting areas with a high-temperature-resistant protective film (polyester or PVC film with adhesive backing). This prevents laser spatter or heat from scorching the patina and causing color unevenness.
Ensure the film does not cover the cutting path-leave a 5–10 mm clear margin along the cut line to avoid film melting and contaminating the cut edge.
After cutting, peel off the film immediately and wipe the surface with a dry cloth to remove residual adhesive.
3. Check and Correct Plate Flatness
Use a straightedge and feeler gauge to check flatness: The maximum allowable warpage is ≤ 1 mm/m for precision cutting (e.g., decorative patterns).
If warpage exceeds the limit, flatten the plate first (via cold leveling) before laser cutting-this ensures the plate lies flat on the cutting bed and maintains a stable distance from the laser nozzle.
4. Clean the Cutting Bed and Secure the Plate
Remove debris (metal chips, dust) from the laser cutting bed to avoid scratching the plate's bottom surface during processing.
Use vacuum suction or clamping fixtures to fix the plate firmly-prevent vibration or displacement during cutting (critical for complex shapes or long cut paths). For thin plates (<3 mm), use a honeycomb bed to reduce thermal deformation.
5. Edge Preparation for Thick Plates (≥12 mm)
Deburr Pre-Cut Edges: If the plate has rough or burrs on the original edges, grind them smooth to avoid affecting the laser's initial penetration.
Pre-Heat (Optional): For plates ≥25 mm thick, pre-heat the cutting area to 100–150°C (using a low-power laser or hot air gun) - this reduces the laser power required for full penetration and minimizes the heat-affected zone (HAZ).
