Granite bases are widely used in precision instruments, optical equipment, and machinery manufacturing due to their excellent hardness, high stability, corrosion resistance, and low expansion coefficient. Their packaging and storage are directly related to product quality, transport stability, and longevity. The following analysis covers packaging material selection, packaging procedures, storage environment requirements, and handling precautions, and provides a systematic solution.
1. Packaging Material Selection
Protective Layer Materials
Anti-Scratch Layer: Use PE (polyethylene) or PP (polypropylene) anti-static film with a thickness of ≥ 0.5mm. The surface is smooth and free of impurities to prevent scratches on the granite surface.
Buffer Layer: Use high-density EPE (pearl foam) or EVA (ethylene-vinyl acetate copolymer) foam with a thickness of ≥ 30mm and a compressive strength of ≥ 50kPa for excellent impact resistance.
Fixed Frame: Use a wooden or aluminum alloy frame, moisture-proof (based on actual reports) and rust-proof, and ensure strength meets load-bearing requirements (recommended load capacity ≥ 5 times the base weight).
Outer Packaging Materials
Wooden Boxes: Fumigation-free plywood boxes, thickness ≥ 15mm, IPPC compliant, with moisture-proof aluminum foil (based on actual report) installed on the inner wall.
Filling: Environmentally friendly air cushion film or shredded cardboard, with a void ratio ≥ 80% to prevent vibration during transport.
Sealing Materials: Nylon strapping (tensile strength ≥ 500kg) combined with waterproof tape (adhesion ≥ 5N/25mm).
II. Packaging Procedure Specifications
Cleaning
Wipe the base surface with a dust-free cloth dipped in isopropyl alcohol to remove oil and dust. Surface cleanliness should meet ISO Class 8 standards.
Drying: Air dry or purge with clean compressed air (dew point ≤ -40°C) to prevent moisture.
Protective Wrapping
Anti-static Film Wrapping: Utilizes a “full wrap + heat seal” process, with an overlap width of ≥ 30mm and a heat seal temperature of 120-150°C to ensure a tight seal.
Cushioning: EPE foam is cut to match the base’s contours and bonded to the base using environmentally friendly glue (adhesion strength ≥ 8 N/cm²), with a margin gap ≤ 2mm.
Frame Packaging
Wooden Frame Assembly: Use mortise and tenon joints or galvanized bolts for connection, with gaps filled with silicone sealant. The frame’s inner dimensions should be 10-15mm larger than the base’s outer dimensions.
Aluminum Alloy Frame: Use angle brackets for connection, with a frame wall thickness ≥ 2mm and anodized surface treatment (oxide film thickness ≥ 15μm).
External Packaging Reinforcement
Wooden Box Packaging: After the base is placed in the wooden box, air cushion film is filled around the perimeter. L-shaped corner guards are installed on all six sides of the box and secured with steel nails (diameter ≥ 3mm).
Labeling: Affix warning labels (moisture-proof (based on actual reports), shock-resistant, and fragile) are applied to the exterior of the box. Labels should be ≥ 100mm x 100mm and made of luminous material.
III. Storage Environment Requirements
Temperature and Humidity Control
Temperature range: 15-25°C, with a fluctuation of ≤±2°C/24h to prevent micro-cracking caused by thermal expansion and contraction.
Humidity Control: Relative humidity 40-60%, equipped with industrial-grade filtration (based on clinical results, with a specific volume of ≥50L/day) to prevent alkali-silica reaction-induced weathering.
Environmental Cleanliness
The storage area must meet ISO Class 7 (10,000) cleanliness standards, with an airborne particle concentration of ≤352,000 particles/m³ (≥0.5μm).
Floor Preparation: Epoxy self-leveling flooring with a density ≥0.03g/cm² (CS-17 wheel, 1000g/500r), dustproofing grade F.
Stacking Specifications
Single-layer stacking: ≥50mm spacing between bases to facilitate ventilation and inspection.
Multi-layer stacking: ≤ 3 layers, with the lower layer bearing a load ≥ 1.5 times the total weight of the upper layers. Use wooden pads (≥ 50mm thick) to separate the layers.
IV. Handling Precautions
Stable Handling
Manual Handling: Requires four people working together, wearing non-slip gloves, using suction cups (≥ 200kg suction capacity) or slings (≥ 5 stability factor).
Mechanical Handling: Use a hydraulic forklift or overhead crane, with the lifting point located within ±5% of the base’s center of gravity, and a lifting speed ≤ 0.2m/s.
Regular Inspections
Appearance Inspection: Monthly, primarily inspecting for damage to the protective layer, frame deformation, and wooden box decay.
Precision Retest: Quarterly, using a laser interferometer to check flatness (≤ 0.02mm/m) and verticality (≤ 0.03mm/m).
Emergency Measures
Protective layer damage: Immediately seal with anti-static tape (≥ 3N/cm adhesion) and replace with a new film within 24 hours.
If humidity exceeds the standard: Activate specific clinical efficacy measures and record data. Storage can resume only after humidity returns to the normal range.
V. Long-Term Storage Optimization Recommendations
Vapor Corrosion Inhibitor (VCI) tablets are placed inside the wooden box to release rust-inhibiting agents and control corrosion of the metal frame.
Smart Monitoring: Deploy temperature and humidity sensors (accuracy ±0.5°C, ±3%RH) and an IoT platform for 24/7 remote monitoring.
Reusable Packaging: Utilize a foldable aluminum alloy frame with a replaceable cushioning liner, reducing packaging costs by over 30%.
Through material selection, standardized packaging, meticulous storage, and dynamic management, the granite base maintains stable performance during storage, keeps the transport damage rate below 0.5%, and extends the storage period to over 5 years.
Post time: Sep-10-2025