Pressing
The veneer pressing process is the production stage in which veneer sheets that have passed through the gluing phase and have been stacked in a cross-grain arrangement are compressed under high pressure and temperature to form plywood panels. Pressing is the critical stage that definitively determines the inter-layer bonding strength, surface quality, and dimensional stability of the panel.
Why Is Pressing So Critical?
For the adhesive applied between the veneer sheets during the gluing stage to be fully activated and form a strong bond, both sufficient pressure and sufficient temperature are required. If pressure is insufficient, gaps remain between the layers and bonding weakens. If temperature is insufficient, the adhesive cannot fully cure and the panel may delaminate over time. Correct adjustment of pressing parameters is therefore the fundamental guarantee of panel quality.
Cold Pressing and Hot Pressing
Two basic pressing methods are applied in plywood production.
Cold pressing is applied immediately after the gluing process. The veneer package is compressed at room temperature under high pressure. The purpose of this stage is to ensure the adhesive penetrates the veneer surface evenly and to prevent the sheets from shifting. After cold pressing, the panel achieves initial bonding and is ready for hot pressing.
Hot pressing is the stage where the actual bonding takes place. The panels are placed between high-temperature press plates. Temperature and pressure are applied simultaneously to fully activate and cure the adhesive. The hot pressing duration, temperature, and pressure are precisely adjusted according to panel thickness, number of layers, and the type of adhesive used. It is critical that all panels are loaded into the hot press at the same time; because if the adhesive begins to cure before entering the press, bonding quality is compromised.
Pressing Parameters
At Alesta Naturel facilities, pressing parameters are determined separately for each product. Pressure is generally set between 10 and 20 kg per square meter. Temperature varies between 100 and 150 degrees depending on the type of adhesive used. Pressing duration can range from a few minutes to half an hour depending on panel thickness. All parameters are continuously monitored by automatic control systems, and immediate intervention is made when necessary.
Post-Pressing Operations
Panels coming out of the pressing stage are immediately transferred to cooling racks. Allowing the panels to cool gradually is important for maintaining dimensional stability. Once cooling is complete, the panels proceed to the quality control stage, where dimensional measurement, surface inspection, and bonding tests are carried out.
As Alesta Naturel, we carry out the pressing process to European quality standards at both our Ukraine and Sakarya Akyazı facilities. With our modern press equipment and precise control systems, we ensure consistent, high-quality plywood production in every batch.
For detailed information about our pressing process and products, you can contact our team.
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Cold pressing ensures the adhesive penetrates the veneer surface evenly and prevents the sheets from shifting.
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Hot pressing fully activates the adhesive with high temperature and pressure, forming a strong bond.
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Pressure, temperature, and duration are precisely adjusted according to panel thickness and adhesive type.
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After pressing, panels are slowly cooled to preserve dimensional stability.
F.A.Q
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What is the difference between cold pressing and hot pressing?
Cold pressing is the preliminary stage that ensures the adhesive penetrates the veneer surface evenly. Hot pressing is the main bonding stage where the adhesive fully cures under high temperature and pressure and the panel achieves its final strength.
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How are pressing pressure and temperature determined?
Pressure and temperature are determined according to panel thickness, number of layers, and the type of adhesive used. At Alesta Naturel, separate parameters are defined for each product type and continuously monitored by automatic control systems.
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What is the effect of insufficient pressing on panel quality?
Insufficient pressure leaves gaps between layers, while insufficient temperature prevents the adhesive from fully curing. Both reduce the panel's bonding strength and can cause layer delamination over time.
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Why are panels cooled slowly after pressing?
Rapid cooling can cause internal stresses and dimensional distortion in the panel. Slow and controlled cooling preserves the panel's flatness and dimensional stability, preventing issues during cutting and surface finishing stages.
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Should automatic loading be used in the cold press?
Automatic loading provides significant advantages in the cold press. With manual loading, shifting and misalignment between sheets can occur, leading to irregularities at panel edges and increased waste. Automatic loading systems place each sheet precisely, increase loading speed, and reduce labor costs. Especially in high-volume production, automatic loading is the preferred method for both quality consistency and efficiency.
