Production Process Report of Primed Finger-Jointed Pine Wood Molding
1. Introduction
Primed finger-jointed pine wood molding is an eco-friendly wood product widely used in interior decoration, furniture edge banding, and architectural structures. By utilizing finger-jointing technology, it enhances wood utilization and mechanical strength, while the specialized coating treatment provides moisture resistance, abrasion resistance, and aesthetic appeal. This report details the entire production process from raw materials to finished products.
2. Raw Material Preparation
- Pine Wood Selection
- Log Procurement: High-quality pine species (e.g., Mongolian Scotch Pine, Radiata Pine) are selected, with log diameters ≥20 cm and no visible decay, insect damage, or cracks.
- Cutting and Grading: After debarking, logs are cut into boards (30–50 mm wide, 15–25 mm thick) using a multi-blade saw. Boards are graded by grain pattern and color consistency.
- Drying Process
- Kiln Drying: Boards are stacked and dried in a kiln with a temperature gradient (50°C → 80°C → 60°C) and humidity reduction (80% → 12%). Final moisture content: 8%–10%.
- Equilibration: Boards are conditioned for 72 hours post-drying to relieve internal stress and ensure dimensional stability.
3. Finger-Jointing Process
- Finger Profiling and Gluing
- Finger Machining: Automated finger-jointing machines (e.g., Homag Group equipment) create trapezoidal finger joints (depth: 8–12 mm, pitch: 3–5 mm).
- Adhesive Preparation: Two-component polyurethane adhesive (base:curing agent = 10:1) is used, with viscosity 3,000–5,000 cps and a 30-minute pot life.
- Joint Assembly and Curing
- High-Pressure Bonding: Adhesive-coated boards are longitudinally aligned and pressed under hydraulic pressure (1.5–2.5 MPa) for 60–90 seconds.
- Curing: Jointed boards are cured in a 50°C chamber for 4–6 hours, achieving a shear strength ≥10 MPa.
- Sanding and Thickness Calibration
- Rough Sanding: Wide-belt sanders (120-grit abrasive) remove joint irregularities, ensuring thickness tolerance ±0.2 mm.
- Fine Sanding: 240-grit abrasive achieves a surface roughness Ra ≤6.3 μm.
4. Coating Treatment
- Coating Formulation
- Base Composition: Water-based acrylic resin (60%), nano-grade diatomite (25%), wood fiber (10%), defoamer (5%).
- Viscosity Adjustment: Diluted with deionized water to a viscosity of 25–30 seconds (measured by a #4 Ford cup).
- Coating Application
- Primer Coating: Roller-coating applies an 80–100 μm wet film, dried at 60°C for 15 minutes.
- Top Coating: Two spray coats achieve a total dry film thickness of 150–180 μm, with 10-minute leveling intervals.
- Surface Finishing
- Texturing: Wire brush machines create 0.1–0.3 mm deep grain patterns for a distressed appearance.
- UV Curing: UV lamps (wavelength 365 nm, power 80 W/cm) cure the coating in 3–5 seconds, achieving a pencil hardness of 2H.
5. Quality Control Standards
- Physical Performance Testing
- Bending Strength: ≥45 MPa (GB/T 17657-2013 standard).
- Moisture Content: 8%–12% (tested via multi-point electronic moisture meter).
- Visual Inspection
- Dimensional Tolerance: Length ±1 mm, width ±0.5 mm, warpage ≤1 mm/m.
- Surface Quality: No bubbles, drips, or coating defects; color difference ΔE ≤1.5 (spectrophotometer).
- Environmental Compliance
- VOC Emissions: ≤50 mg/L (GB 18580-2017 standard).
- Formaldehyde Content: ≤0.3 mg/L (climate chamber method).
6. Packaging and Storage
- Moisture-Proof Packaging
- Vacuum-sealed PE film (10 pieces/bundle) + corrugated boxes with desiccant (silica gel, 1 g/m³).
- Storage Conditions
- Temperature: 20–25°C; humidity: 40%–60%; stacking height ≤2 m; avoid direct sunlight.
7. Environmental and Safety Measures
- Dust Control
- Centralized dust collection (airflow ≥5,000 m³/h) with bag filters (emission ≤10 mg/m³).
- Wastewater Treatment
- Coating wastewater treated via flocculation + biological processes (COD ≤50 mg/L).
- Worker Protection
- N95 masks, noise-canceling earmuffs, and regular occupational health checkups.
8. Conclusion
The production of coated finger-jointed pine wood molding integrates precision machining and eco-friendly coating technologies. Strict process controls and quality assurance ensure high mechanical strength and decorative performance. Future advancements may include AI-based visual inspection and water-based UV coatings to enhance efficiency and sustainability.
Appendix: Process flowcharts, equipment specifications, and test reports can be appended (to be populated with actual data).
For further technical details or parameter optimization, please specify requirements.
