Wood-dowel rotation welding – a heat-transfer model

Abstract

The relationship between temperature, time of friction and thermal flux for high-speed rotational wood-dowel welding has been modelled through a heat-transfer model. It was shown that the interface temperature could be estimated as a function of the friction time by the general equation T 0 = T i + 2βuτ√α/h√π √t, where T 0 – temperature at the welding interface, T i – initial temperature of the wood, t – time, τ – the friction stress, u – the rate of rotation or vibration, β – the fraction of mechanical energy convertible into thermal energy, and h and α are, respectively, the thermal conductivity and diffusivity of the wood. For both the rotation welding and linear welding systems, the value of β is found to be 0.080±0.01. The results obtained for dowel rotation welding indicate that a temperature of 180°C is optimal for rotational dowel welding. The model was validated from experimental data on rotational dowel welding for the portion of the curve in which temperature increased as a function of time. Furthermore, it was also validated from experimental data for linear vibration welding.