Reduction of Residual Stresses in Medium Density Fibreboard. Part 2. Effects on Thickness Swell and Other Properties

Abstract

Summary The Taguchi method of experimental design has been utilised to investigate various treatments for relieving the residual stresses present in medium density fibreboard (MDF). These treatments involved subjecting panels to different combinations of heat, moisture and pressure. This paper reports on the Taguchi analysis of the internal bond strength, surface layer tensile modulus, surface layer tensile strength and thickness swell of the treated specimens. These properties were measured to indicate whether the treatments had any effect on panel strength and dimensional stability. A strong correlation between residual stresses and thickness swell has been identified. When the change in residual stress through the outer layers of a panel is almost completely removed, a reduction in thickness swell of approximately 20% for a 24 hour water soak is observed.