Effects of screw sizes on load bearing capacity and stiffness of five-sided furniture cases constructed of particleboard and medium density fiberboard

Abstract

This study was carried out to determine the effects of the screw sizes and board material type oil the load bearing capacity and stiffness of five-sided furniture cases. Nine sizes of screws that included 3.5 by 40, 3.5 by 45 3.5 by 50, 4 by 40, 4 by 45 4 by 50, 5 by 40, 5 by 45, and 5 by 50 were used for assembling the five-sided cases. Particleboard (PB) and medium density fiberboard (MDF) were utilized for constructing the five-sided cases. The five-sided cases were tested under static performance tests by supporting at three points. Experimental results indicated, in general, the five-sided cases constructed of MDF yielded significantly higher load bearing capacities than those of PB, but the significance of MDF cases over PB cases in stiffness depends on screw diameters. Screws with 5 mm in diameter and 50 turn in length should be the choice for construction of cases with PB materials to yield the maximum performance in load bearing capacity and stiffness. Due to the interaction effect there is no screw size selection for MDF cases to reach maximum performance in load bearing capacity and stiffness at the same time. The maximum load bearing capacity of five-sided cases constructed of MDF materials evaluated in this study call be obtained if 5 mm diameter and 50 mm long screws are used, while the maximum stiffness of the MDF cases call be resulted by using 5 mm diameter and 45 mm long screws. The comparisons of the theoretical stiffness values and actual test stiffness values indicated that the average rigidities of the screw corner jointed five-sided cases evaluated ill this study could be estimated with the developed predictive formula by the previous researchers.