Methods and Requirements for Improving the Quality of lamination
In the production of density board lamination, quality problems often arise because of some reasons. In fact, there are many factors affecting the quality of lamination. When we encounter problems, we should analyze them concretely, find out the reasons and find ways to remedy them.
- Even within the tolerance allowed by the national standard, the requirement of lamination can not be fulfilled. Fixed thickness sanding should be carried out before lamination.
- Before gluing, the board surface should be cleaned to prevent dust from floating on the surface, which will affect the full contact between the lamination material and the base material.
- The moisture content of thin wood or base material should be uniform and uniform. The moisture content of thin wood is higher than that of base material, but the moisture content of thin wood should not be too high. Otherwise, the viscosity of glue will be reduced. At the same time, the shrinkage of thin wood after drying is too large, cracks and wrinkles will appear.
- Adhesive coating and hot-cold pressing should adjust the viscosity and amount of adhesives evenly so as to be suitable for production site without degumming and penetration. If the viscosity is too low, easy to overflow, resulting in glue shortage, if too high, then poor leveling, uneven glue coating, resulting in local glue shortage. Strictly abide by the operating standards, in the container with glue, stirring, do not allow direct operation on the roller coating machine, otherwise it will make the proportion of adhesives uneven, while damaging the rubber layer on the roller.
- The time before hot pressing should not exceed the aging time of the adhesives used. The optimum number of hot-pressing layers is 4 to 5 layers. If the number of pressing plates is increased, the aging time can be prolonged, the amount of glue can be increased or the viscosity of glue can be reduced.
- When problems such as bubbling and degumming occur in production, some minor techniques can be used to remedy them in time. The glue is injected directly into the bubbling area with syringe, or the bark of the bubbling area is cut along the wood grain with a knife blade, then the glue is squeezed directly with strong glue, and then pressed flat with an iron. When the bubbling area is large, the thin wood at the bubbling place can be removed, the base surface cleaned, and then laminationd with similar thin wood. The periphery of the patch should be baroclinically pressed on the original thin wood, so that the periphery of the board is tight.