Modeling vertical density profile formation for strand-based wood composites during hot pressing: Part 1. Model development

Abstract

During the manufacturing of wood composites, mats of resinated fibers, particles or strands are consolidated under heat and pressure to produce panels with the necessary strength and stiffness properties. As the mat consolidates a vertical density profile (VDP) is established and it has a significant impact on panel properties. In order to tailor the VDP of the panel to various end-use applications, a means of describing of the effect of pressing variables on the development of the VDP is needed. In this paper, a comprehensive model is established to simulate the formation of VDP for strand-based wood composites. Based on the strand compression properties during hot pressing, this model can predict the in situ formation of density profile in combination with an existing heat and mass transfer model. As a structural model, it can predict the density distributions in both horizontal and vertical directions of the panel. Also it can help clarify the importance of pressing parameters and predict the effects of these parameters on VDP formation.