Influence of vibrating recoating mechanism for the deposition of powders in additive manufacturing: Discrete element simulations of polyamide 12

Improving the quality of the powder layers used in selective laser melting is a crucial step in bringing additive manufacturing to an industrial standard process. In this work, the effect of vibrations applied to the recoating mechanism (standard blade and roller) on the quality of the powder bed is evaluated. A numerical study using a realistic particle model of polyamide 12 is performed to evaluate the influence of frequency and amplitude in the porosity of the powder layer. Small frequency and amplitude, combined with small recoating velocity, lead to a reduction in the porosity of the granular bed. Large frequency and amplitude, however, lead to a vibro-fluidized state of the particles, loosening the granular bed and increasing the porosity. For practical applications, the choice of frequency and amplitude must be considered in combination with a specific translational velocity of the recoating mechanism.