Reduction of residual stresses in medium density fibreboard - Part 2. Effects on thickness swell and other properties

The Taguchi method of experimental design has been utilised to investigate various treatments for relieving the residual stresses present in medium de nsity fibreboard (MDF). These treatments involved subjecting panels to diff erent combinations of heat. moisture and pressure. This paper reports on th e Taguchi analysis of the internal bond strength, surface layer tensile mod ulus, surface layer tensile strength and thickness swell of the treated spe cimens. These properties were measured to indicate whether the treatments h ad any effect on panel strength and dimensional stability. A strong correla tion between residual stresses and thickness swell has been identified. Whe n the change in residual stress through the outer layers of a panel is almo st completely removed. a reduction in thickness swell of approximately 20% For a 24 hour water soak is observed.