PREPARATION AND SELECTIVE LASER SINTERING OF WOOD-PLASTIC COMPOSITE POWERS AND POST PROCESSING

A mixing process was successfully developed to prepare Wood-Plastic Composite(WPC) powders. Before mix, the wood flour is alkalized for reducing the hydrophilic nature of wood fiber and improving the wettability and the adhesion actions of the interface. Green parts were formed from WPC by selective laser sintering (SLS) process, when the applied laser energy density was 283W/mm(2), the SLS green parts had sufficient strengths for features as small as 0.1mm to be built and post-processed, and relatively high dimensional accuracy. In order to further improve the properties of the pattern, the post-processing infiltration with wax - is introduced. Through post-processing, the void fraction is decreased from 51% to 7%, the mechanical properties are significantly improved, the average tensile strength, bending strength, and impact strength are 1.157 MPa, 2.72 MPa and 1.4125KJ/m(2). Compared with those without post processing, the tensile strength is 87 times higher than without post processing and the bending strength increased by 384% while the impact strength increased by 94%. After post-processing, surface quality is greatly improved, Ra is below 0.013mm on average, and after grinding and polishing the surface is smoother and Ra is below 0.007mm on average.