The effect of the bottom-tops layer chip ratio and sanding allowance on the board properties in the surface coating process of low density particle boards

Forest resources to meet the wood needs of the increasing human population in the world are limited. For this reason, industrial waste and wood left over from log production are used in wood composite production. The most commonly produced wood composites are medium density fiberboard (MDF) and particleboard. These boards have dominated the world board market in the last 20 years. This increase in board production has made it difficult for manufacturers to access wood raw materials. For this reason, manufacturers have chosen to use less wood raw material by producing low density boards in order to increase their competitiveness. Producing low density boards causes quality problems in the laminate coating of the top surface of the board. For this reason, the surface (Surface Layer: SL) and core (Core Layer: CL) layer ratios of three-layer chipboards produced at low density must be optimally determined. Because as the SL layer ratio increases, surface quality increases, but costs also increase. Additionally, one of the important factors affecting surface quality is sanding tolerance. Sanding tolerance should be kept as low as possible. This is not always possible. For this reason, the amount of SL and sanding tolerance that provides the best surface quality should be determined. In order to determine this, it is necessary to analyze the mechanical and physical properties of the board with different SL ratios and different sanding tolerances in particleboard produced at different densities, as well as the abrasion, scratching, color change and stain resistance after melamine pressing. In this study, 12 particleboard samples were produced in two different densities, three different SL/CL layer ratios and two different sanding tolerances (2 x 3 x 2 = 12) for the optimum board production mentioned above. Physical and mechanical characterizations of the boards were made according to the relevant Turkish Standards. After the boards were coated with laminate, their abrasion, scratch and stain resistance were analyzed. Significant differences between the samples were revealed by One-way Anova analysis using the SPSS package program. To determine the best example among the samples, the GRAY analysis method, one of the multi-criteria decision-making methods, was used. As a result of the analysis, it was determined that the best sample was with a density of 560, a ratio of 32 % SL – 68 % CL and a thickness of 18 mm after sanding.