Study On Selective Laser Sintering Mechanism And Mechanical Properties Of Carbon Nanotube/Wood-Plastics Composites Parts

Selective laser sintering(SLS),one of advanced additive manufacturing technologies,enables rapid production of small-batch parts with complicated structures without the need of molds and support structures.SLS uses a wide range of raw materials,but the cost is high,limiting its development.Wood-plastic composite is low-cost and environmental protection,as a new type of SLS material.In order to improve the mechanical properties of the composites and expanding the application scope of composites in the SLS area,the industrial carbon nanotubes(CNT)are selected as reinforcements to improve the mechanical properties of wood-plastic composites.This paper selects pine wood powder,polyethersulfone resin(PES)and industrial grade CNT as raw materials,and prepares industrial grade carbon nanotube/wood-plastic composites powder according to the designed mixed powder process flow.The differential scanning calorimeter(DSC)is used to determine the glass transition temperature of the composite powders as a criterion for selecting the preheating temperature.The process parameters of the composites powder by laser sintering are determined by multiple single-layer sintering experiments.Scanning electron microscopy(SEM)is used to observe the microstructure of the composite powders and SLS parts.The evolution of the particle morphology during the sintering process is analyzed.After studying the sintering mechanism of the composites,an industrial carbon nanotube/wood is established,so as to provide theoretical support and basis for the study of mechanical properties of SLS parts.The effects of CNT content,CNT dispersion,and wood flour particle size on the mechanical properties of carbon nanotube/wood-plastic composites parts are investigated.Carbon nanotubes/wood-plastic composites powders are prepared using CNT with contents of 0.05%,0.1%and 0.15%,respectively,and SLS tests are carried out to test the mechanical properties and SEM observations of the SLS parts.It is found that when the CNT content is 0.1%,the mechanical properties are significantly improved compared to the SLS parts without CNT.In order to improve the agglomeration phenomenon of CNTs,CNTs are dispersed by ultrasonic dispersion method.It is found through SEM that when the dispersibility of CNTs became better,only a small amount of CNT could make SLS parts achieve higher mechanical properties.The effect of wood flour particle size on the mechanical properties of SLS parts is studied by using three different particle sizes(100 mesh,150 mesh,and 200 mesh)wood flour to prepare carbon nanotubes/wood-plastic composites.At 100 mesh,the mechanical properties of SLS parts are optimal.The research in this paper has important theoretical and engineering values to promote the application of wood-plastic composites in the field of SLS.