Influence of Refining Parameters on Fiber Granulometry, Surface Quality, and Mechanical Properties of Embossed MDF Door Panels

Medium-density fiberboard (MDF) is widely used for embossed door panels. The fiber refining process is crucial for determining both surface quality and mechanical performance of these panels. This study investigated how different refining conditions affect fiber granulometry, surface quality, and mechanical properties of embossed MDF door panels. Three key refining parameters were investigated: digester steam pressure (0.8 and 0.9 MPa), refiner specific energy (70 and 80 kWh/t), and refiner differential pressure (24, 35, and 50 kPa). Panel properties were evaluated in terms of vertical density profile, surface roughness, bending properties, and cleavage strength. Statistical analysis revealed that refining parameters significantly affected fiber granulometry, as well as the average and surface density of the panels. Surface roughness, however, showed minimal variation under the refining conditions considered. In contrast, the bending properties—modulus of rupture (MOR) and modulus of elasticity (MOE)—were significantly improved, with MOR and MOE increasing by up to 12% relative to the control (48.0 vs. 42.7 MPa and 4.6 vs. 4.1 GPa, respectively). Cleavage strength also varied with refining conditions but remained comparable to the control across all treatments. Overall, the results indicate that optimized refining conditions can enhance MDF door panel performance, particularly bending properties, without compromising surface quality or cleavage strength.