Modeling and numerical research on powder paving process of nylon powder in selective laser sintering

Nylon powder is the most mature raw material which is commonly used in selective laser sintering (SLS). The flowability of nylon powder influences the smoothness and density uniformity of the resulting powder bed during the process of powder paving, which in turn affects the quality of the printing component. The powder paving processes of nylon powder in SLS were simulated using the discrete element method to research the influence of process parameters and distribution of particle size on the quality of powder paving. Powder paving quality was characterized by build zone dense characteristic and density uniformity. Our numerical results revealed that the density uniformity and dense characteristic of build zone increase with the increase in roller translational velocity when it is less than 30 mm/s and the density uniformity and dense characteristic of build zone decrease with the increase in roller translational velocity when it is greater than 30 mm/s. It was also shown that the dense characteristic of build zone increases with the increase in roller diameter and vibration frequency and the density uniformity of build zone decreases with the increase in standard deviation of particle size distribution.