Laser intensity effect on mechanical properties of wood–plastic composite parts fabricated by selective laser sintering

Abstract

In this article, the relationship between the mechanical properties of wood–plastic composite (WPC) parts fabricated by selective laser sintering (SLS) and the laser intensity is determined. Green parts were formed from WPC by SLS process, the SLS green parts had sufficient strengths for features to be built with relatively high dimensional accuracy. In order to improve the mechanical properties of the parts to better level, the post-processing – infiltration with wax – is used. Experiments for studying mechanical properties of WPC parts with laser intensity growing are carried on, the result is as following: because interfacial adhesion of copolyester and densification are improved with laser intensity growing, impact strength increased gradually either in green part style or in wax-infiltrated part style, tensile strength and bending strength of wax-infiltrated parts increased gradually. The tensile strength improved 191% and the bending strength improved 17%, with the increase in laser intensity from 226 Watt/mm2 to 311 Watt/mm2; the impact strength of green parts improved 543% and the impact strength of wax-infiltrated parts improved 147%, respectively, by increasing the laser intensity from 226 Watt/mm2 to 340 Watt/mm2. But when the laser intensity is greater than 311 Watt/mm2, the tensile strength and bending strength decreased for further increasing of the laser intensity, leading to higher temperature, making the melt viscosity of the copolyester drop.