Optimization of machining parameters of rotational welding technology
University of New Brunswick
The wood welding technology has been used to make environmentally friendly wood products. This study was aimed to optimize the rotational welding parameters to produce high-strength wood joints using the Response Surface Methodology. Black spruce (Picea mariana) was used as substrates; sugar maple (Acer saccharum) and hickory (Carya spp.) were used as dowels of a diameter of 0.75 inch. Wood joint specimens were made taking three welding parameters into account, including hole-diameter (Φ), density of wood substrate (ρ) and rotational speed (S[subscript R]). Hole-diameter/dowel-diameter ratio (Φ[subscript φ]) was employed to discuss the results. The push-out tests were conducted using a universal mechanical testing machine. The effects of each parameter and their interactive effects on the maximum push-out load (P[subscript max]) and stiffness (K) of joints were examined. It was found that among the three chosen parameters, Φ was the most significant factor influencing P[subscript max] and K. S[subscript R] and ρ did not have a significant effect on two responses. The optimum welding parameters were found to be that Φ was 0.64 inch, ρ was 0.45 g/cm³ and S[subscript R] was 900 rotation per minute. The joint verification test using the optimized parameters showed that P[subscript max] and K were 700% and 225% larger, respectively, than those of push-in maple dowelled specimens. Another verification test showed that P[subscript max] and K increased by 415% and 220%, respectively, compared to the push-in hickory doweled specimens. A potential of applying this technology could be to reinforce existing wood joints or make laminated wood products such as beams. Keywords: Push-out load, stiffness, density, hole diameter, rotational welding, wood joints, hardwood dowels.