Molecular Dynamics Simulation And Experimental Research Of Laser Sintering Cellulose/Pes Powder

Selective laser sintering (SLS) technology is a manufacturing method based on the additive principle. Because of its advantages such as no waste, extensive material selection and freedom fabrication, SLS has attracted widespread attention from home and abroad. Currently high cost of feedstock of this technology becomes one of the main factors inhibiting the development of selective laser sintering technology. Therefore, developing a new material with low cost, high strength and good toughness has been one of the research directions in this field. The WPC is a low-cost, green composite, which can be used for SLS, however there are still problems of poor interface compatibility and low strength in sintered parts. It is needed for further studying to improve its properties.A new kind of raw material was presented in this paper that using cellulose of low cost, biodegradable alternative to conventional wood flour as the filler, mixed with polyether sulfone (PES), polypropylene (PP) by a specific ratio, respectively, which could be used as the feedstock of the laser sintering experiment. In order to optimize the distribution, mixture ratio as well as process parameter of preheat temperature, this paper adopted the Cellulose/PES and Cellulose/PP blends as the study objects, molecular simulation was used to build the models, and through molecular dynamics simulations to the models, it can be obtained that the compatibility of cellulose with these two polymers, mechanical properties of different mixture ratios and the binding energy of the Cellulose/PES under thermal effect. The simulation results showed that compared to the Cellulose/PP, Cellulose/PES had higher mixed energy, which was more suitable for SLS process technology. The ratio of the optimum mechanical properties of sintered parts of cellulose mixed with PES and the preheating temperature range of the two phases having the strongest interaction were gotten.Laser sintering comparative experiment of these two mixtures were carried based on these simulated results above. Optimal process parameters applied to Cellulose/PES were provided. Through mechanical testing, the results showed that compared with the previous wood-plastic hybrid powder materials, the Cellulose/PES (25/75) had significant advantages in mechanical properties. Two post-processing methods were offered in this paper, and through scanning electron microscope, the impact of post-processing techniques on the performance of parts were analyzed, getting that the mechanical properties and surface properties of the sintered parts has been greatly improved by post-processing. The simulation results have been verified by SLS experiments. The established model of Cellulose/PES blends and simulation method can be used for guiding the direction of dynamic experiment.