There are several ways to prevent the deformation of wooden products:
L. water storage method
Water storage method is a relatively primitive way to decrease the residual growth of log. Log by long period of water storage, become soft, residual stress gradually released during growth. But this method increases the log storage cycle and the amount of funds used, suitable for water transport and water storage conditions of the occasion.
2 heat treatment method
The experiment indicated that the wood fiber and lignin can be heated by hot water, steam, furnace gas or flue gas before sawing, so that the wood fiber and lignin can be softened, and the residual growth stress can be eliminated. Specific measures for:
With 70 to 80 C water treatment, or make the log internal temperature reaches more than 80 C using steam, furnace gas heating, or the use of more than 150 C of flue gas treatment, at different moments and Heshui rate control, the timber exterior growth residual stress below 50 per cent, and thoroughly eliminate. Through comparative experiment, heat treatment after sawing lumber delivery end crack less, flat plate surface, especially radial cutting edge of the plate is twists and turns (transverse) decreases, can raise the material rate of 4% ~ 6%. But, the use of gas as a heat source for processing, timber exterior Heshui rate in the fiber saturation point (FSP) less prone to cracking appearance, which should handle the manipulation of temperature and humidity.
3 other ways
In addition to the above approach, and the use of tree leaves method, namely the trees in pre harvest a year or earlier to remove branches, stop its growth, to force the trunk growth stress equilibrium, growth rates should be 20% ~ 30%, reach the same effect with the water storage. In addition, the use of genetic selection, silviculture and growth ring cut method and decline or improve growth should force research is also underway.