How to Make Wooden Boards for Prefabricated Houses
Making wooden boards for prefabricated houses (taking wooden formwork as an example) involves six major processes: raw material pretreatment, veneer sorting and splicing, mat assembly and hot pressing, surface treatment, cutting and edge sealing, and initial quality inspection. The specific steps are as follows:
1. Raw Material Pretreatment
Select uniformly textured woods such as pine and fir. Use a multi-blade saw to cut the logs into veneers that are 10-15mm thick. Then, air-dry them manually for 7-10 days to remove excess moisture, preventing subsequent moisture-related deformation that could affect the precision of concrete forming. If the veneers have minor insect damage or knots, they should be treated through processes such as sanding and filling to ensure surface flatness.
2. Veneer Sorting and Splicing
After air-drying, the veneers should undergo a "trimming-sorting" process to eliminate defective pieces with severe insect damage, cracks, or uneven thickness. Adopt a cold-press splicing process to join short veneers into standard-length (e.g., 2440mm) base materials. Use environmentally friendly urea-formaldehyde resin adhesive during splicing, with the glue application amount precisely controlled at 180-220g/㎡. Apply a pressure of 0.8-1.0MPa using a cold press and maintain it for 30-40 minutes to ensure strong bonding at the spliced joints. Meanwhile, the formaldehyde emission should be ≤0.124mg/m³ (in compliance with the national standard GB 18583-2008).
3. Mat Assembly and Hot Pressing
Based on the required formwork thickness (e.g., 12mm, 18mm), assemble the mats following the principle of "parallel grain + cross grain" arrangement. A 12mm formwork usually consists of 5-6 layers of veneers, while an 18mm formwork requires 8-10 layers. This structure significantly enhances bending resistance. After mat assembly, send it into a hot press. Set the temperature at 120-140℃ and the pressure at 1.2-1.5MPa, and hot press for 20-30 minutes. During this period, continuously monitor the temperature and pressure of the pressing plates to ensure full curing of the adhesive, resulting in a compact, bubble-free base material.
4. Surface Treatment
The hot-pressed base material should undergo sanding treatment. Use a double-sided sander with 80-120 grit sandpaper to sand the surface, controlling the roughness at Ra≤6.3μm to remove burrs and adhesive residues. Then, cover it with waterproof impregnated paper (e.g., melamine-impregnated paper) and bond it for 10-15 minutes through low-temperature hot pressing (80-100℃, 0.8MPa) to improve waterproof performance and reduce concrete adhesion, facilitating demolding.
5. Cutting and Edge Sealing
Use a CNC panel saw to cut the base material into standard sizes (e.g., 2440×1220mm), with an accuracy controlled within ±0.5mm. After cutting, seal the edges of the formwork with PVC edge banding strips. Heat the edge banding machine to 180-200℃ to thermally fuse the edge banding strips with the edges and press them firmly with a pressure roller to prevent moisture absorption and cracking.
6. Initial Quality Inspection
Quality inspectors screen qualified products through visual inspection (no scratches, blisters, or detached edge banding), dimension measurement (error ≤ ±0.5mm), and simple pressure tests to ensure the formwork meets usage standards.
