Generally, the board surface is flat and clean, no water and oil stains are allowed, and there is no phenomenon of edge sliding and gnawing in the effective size. The thickness deviation of the plate should not exceed ± 0.2mm, and the sanding should be uniform, and no sand leakage is allowed; the moisture content of the board should be controlled within the range of 6% - 10%. Because particleboard is mostly purchased, the change of environment can cause the change of moisture content. If the moisture content is too high, it may lead to blasting and delamination during the veneering process; if the moisture content is low or the volatile content of the board is low, the surface may not be well wetted during hot pressing, resulting in lamination of paperboard. Therefore, in the production process, it is necessary to observe and remove the unqualified substrate in time.