Plywood Production Process
The plywood production process can be divided into six stages: log processing, veneer manufacturing, veneer drying and conditioning, gluing and lay-up, hot pressing, and post-processing.
Stage 1: Log Processing
1. Logs are sorted and stacked by species and diameter upon arrival.
2. The debarker removes the bark from logs.
3. Logs are centered using the centering device and fed into the rotary veneer lathe.
4. The lathe peels the log into a continuous veneer ribbon, which is then clipped into sheet veneers.
Stage 2: Veneer Drying
1. Wet veneers enter the dryer to reduce moisture content via hot air or hot rollers.
2. After drying, veneer moisture content is controlled to 8%-12% to ensure subsequent bonding quality.
3. Dried veneers undergo natural conditioning or forced cooling.
Stage 3: Veneer Conditioning
1. Sorting equipment grades dried veneers (face, back, core grades).
2. Repair machines patch defects such as holes or cracks in veneers.
3. Splicing machines join narrow veneers into required dimensions.
4. Conditioned veneers are stacked by grade for later use.
Stage 4: Gluing & Lay-up
1. Core and back veneers receive uniform adhesive application via glue spreader.
2. The lay-up line assembles veneers according to the principle of perpendicular grain orientation between adjacent layers.
3. The assembled veneer stack is sent to the cold press for preliminary bonding under low pressure.
Stage 5: Hot Pressing
1. The pre-pressed stack enters the hot press, where adhesive is cured under high temperature (110-140°C) and high pressure (8-20 kg/cm²).
2. Pressing time depends on panel thickness, typically 30-60 seconds per millimeter.
3. After hot pressing, panels undergo cooling and conditioning to relieve internal stress.
Stage 6: Post-processing & Finished Product
1. Edge trimmers cut rough panels to standard sizes (e.g., 1220×2440 mm).
2. Sanders calibrate panel thickness to ensure tolerance within ±0.2 mm.
3. Finished panels are inspected, graded, and packed for storage.
