1. Wood species and structural characteristics: The size and number of pits and the size of microholes on the pit film vary greatly with the different wood structures of different tree species, so the difficulty of water moving along the path mentioned above is also different, that is to say, wood species is the main internal factor affecting the drying rate.

2. Wood thickness: The general drying process of wood can be seen as the heat and mass transfer process along the direction of wood thickness. With the increase of wood thickness, the distance of heat and mass transfer becomes longer, the resistance increases, and the drying speed decreases obviously.

3. Wood moisture content: below the saturation point of fiber material, with the gradual decrease of moisture content, the transverse diffusion coefficient of adsorbed water decreases, while the diffusion coefficient of water vapor in the cell cavity increases. Due to the small proportion of water vapor diffusion in the cell chamber during the drying process, the lower the water content, the longer the water diffusion path, so the less water, the more difficult to dry.

4. Wood heartwood: There are many inclusions in the heartwood cells of hardwood trees. Most of the stripes in coniferous heartwood are closed, so heartwood is more difficult to dry than sapwood.

5, wood grain direction: wood rays are conducive to water conduction, along the radial direction of the wood water conduction is about 15%-20% greater than along the chord, so the drying speed of chord cutting board is usually faster than the radial cutting board.

These are the five internal factors that affect the material of solid wood office furniture. Although the internal factors can not be controlled, but as long as according to the characteristics of wood reasonable use of drying equipment and process, can improve the drying speed, while maintaining the wood performance, reduce unnecessary losses, improve the drying effect.