The main factors affecting the quality of plywood production
Shandong plywood is a three-layer or multi-layer laminated material, which is made up of wood segments cut into veneers or planned into thin wood, then bonded with adhesives. Usually, odd-layer veneers are used and the fibre directions of adjacent veneers are perpendicular to each other. Plywood is one of the common furniture materials. It is one of the three major wood-based panels. It can also be used for aircraft, ships, trains, automobiles, buildings and packing boxes. A group of veneers are usually bonded vertically to each other in the direction of the adjacent wood grain. Usually, the surface and inner veneers are symmetrically arranged on both sides of the central layer or the core.
In the production of plywood in Shandong Province, almost every process affects the plywood bonding quality in varying degrees. To facilitate mastery, the following aspects are summarized:
_1. Adhesive quality
_is manifested in the properties of synthetic resin adhesives for adhesives, the compounding of various components and the blending process. In recent years, a lot of research work has been done on the components and blending technology of plywood in China, which not only saves a lot of chemical raw materials, reduces the cost of products, but also improves the performance of products, which is the performance of technological progress. In production, only the synthetic resin used has good properties, sufficient bonding strength, reasonable proportion of each component of the adhesive, stable performance of the prepared adhesive, suitable resin content and viscosity, and long enough active period can ensure normal operation and meet the requirements of the product indicators.
_2. Veneer Quality
The quality of veneer, especially its surface state, has a great influence on the bonding strength. The quality of veneer should be paid enough attention to in the preparation of wood section and each process of veneer rotary cutting. Wood softening treatment should be carried out well, and the conditions of rotary cutting should be controlled so that the indexes of veneer are in the optimum value. At the same time, the moisture content and flatness of veneer should be paid attention to.
_3. plywood bonding
Before rubber pressing, attention should be paid to the two links of sizing quantity and slab aging. The glue content is too large, the cost is high; and the glue layer is too thick, the internal stress increases, and it is easy to penetrate; the glue content is too small, which is not conducive to the infiltration of the glue, and the glue layer will be incomplete. The aging time should be appropriate and change with climate change. In order to realize the whole core plate, reduce the core plate lamination and seam separation. Attention should be paid to the speed of pressure reduction of rubber strip, especially to the moisture content in slab.