Abstract:

A new type of wood-plastic mixtures that were used for selective laser sintering(SLS) was proposed with the advantages of low cost and good flexibility. Boxwood/thermoplastic polyurenthane(B/TPU) mixtures containing with the boxwood powder mass fraction of 2%, 5%, 10%, and 15% were prepared by mechanical mixing method, respectively. The thermal properties, mechanical properties, dimensional accuracy and microstructures of the mixtures and laser-sintered parts were tested and characterized. The effects of material ratio and process parameter on formability of laser sintering were investigated. Fractional factorial design method was applied to study the effects of process parameters on the forming properties of the laser-sintered parts. The results showed that laser-sintered boxwood/thermoplastic part with 10% boxwood powder had the best mechanical property when the preheating temperature was 48 ℃, laser power was 14 W, scan speed was 1 600 mm/s, scan spacing was 0.1 mm and layer thickness was 0.1 mm. The properties were summarized as that the tensile strength reached 4.86 MPa, the flexural strength was 9.19 MPa and the elongation at break reached 24.22%.

Key words: wood-plastic mixtures, selective laser sintering, fractional factorial design method, process parameter optimization, mechanical property