The drying process for solid wood strips is crucial for ensuring product quality. Its core objective is to scientifically control the drying process to prevent cracking and stabilize moisture content fluctuations. This process requires coordinated efforts across seven dimensions: pre-drying treatment, drying process selection, temperature and humidity control, intermediate treatment, final treatment, moisture content balancing, and storage and transportation, forming a complete drying control system.
Pre-drying treatment is fundamental. After felling, solid wood strips need to be naturally air-dried to allow the wood to initially adapt to environmental humidity and reduce internal stress. During lumbering, radial-cut boards should be prioritized to avoid producing boards with pith, as the difference in radial and tangential shrinkage near the pith is significant, easily leading to cracking. Simultaneously, the sawing method must be appropriate to reduce wood fiber breakage and provide a uniform material base for subsequent drying.
The choice of drying process directly affects the risk of cracking and moisture content control. Artificial drying, such as hot air drying, vacuum drying, or microwave drying, can more precisely control temperature and humidity, reducing cracking caused by environmental fluctuations during natural drying. Microwave drying utilizes high-frequency electromagnetic waves to evenly evaporate moisture from the wood's interior, preventing surface hardening and making it particularly suitable for drying thick solid wood strips.
Temperature and humidity control are crucial in the drying process. Initially, low-temperature preheating is necessary, with the temperature gradually increased to prevent excessive surface moisture evaporation and cracking. During the middle stage of drying, when the moisture content approaches the fiber saturation point, intermediate treatment is required. This involves steam spraying or humidity regulation to improve the surface plasticity of the wood, eliminate surface hardening and residual stress, and prevent later internal cracking. At this stage, temperature and humidity must be dynamically adjusted according to the wood type and thickness to ensure even moisture migration.
Final treatment is key to stabilizing the moisture content. When the wood's moisture content reaches the target value, a balancing treatment is performed, using fluctuating temperature and humidity to bring the internal and external moisture content of the wood closer to uniformity. For example, briefly raising the temperature, maintaining high temperature and humidity, and then rapidly cooling down, repeating this process, can eliminate residual stress and improve wood stability. After final treatment, the wood needs to cool slowly in a dry environment to prevent cracking due to sudden temperature changes.
Moisture content balance is essential for long-term stability. After drying, solid wood strips need to be stored in a temperature- and humidity-controlled warehouse to balance their moisture content with the environment, reducing the risk of deformation during use. During storage, the wood should be stacked separately, avoiding mixing different tree species or woods with large differences in initial moisture content to prevent mutual influence and moisture content fluctuations.
Controlling the transportation and processing processes is equally important. During transportation, the wood should be wrapped with moisture-proof materials to prevent moisture absorption or loss. Before processing, the moisture content should be tested again to ensure it meets the equilibrium moisture content requirements of the intended use location. If the moisture content is too high, it can be adjusted through secondary drying or humidification treatment; if it is too low, it needs to be sprayed with water to increase humidity and prevent cracking during processing.
Long-term stability maintenance needs to be maintained throughout the product lifecycle. During use, changes in ambient temperature and humidity can cause moisture content fluctuations in wooden bed boards, leading to deformation or cracking. Therefore, it is recommended to maintain stable indoor humidity and avoid direct sunlight or direct airflow from air conditioners onto the bed boards. Regularly using a humidifier or dehumidifier to regulate humidity can extend the lifespan of the bed boards and maintain their appearance and functionality.
