“Sintering” Models and In-Situ Experiments: Data Assimilation for Microstructure Prediction in SLS Additive Manufacturing of Nylon Components

Abstract

<jats:title>ABSTRACT</jats:title><jats:p>Selective laser sintering methods are workhorses for additively manufacturing polymer-based components. The ease of rapid prototyping also means it is easy to produce illicit components. It is necessary to have a data-calibrated in-situ physical model of the build process in order to predict expected and defective microstructure characteristics that inform component provenance. Toward this end, sintering models are calibrated and characteristics such as component defects are explored. This is accomplished by assimilating multiple data streams, imaging analysis, and computational model predictions in an adaptive Bayesian parameter estimation algorithm. From these data sources, along with a phase-field model, bulk porosity distributions are inferred. Model parameters are constrained to physically-relevant search directions by sensitivity analysis, and then matched to predictions using adaptive sampling. Using this feedback loop, data-constrained estimates of sintering model parameters along with uncertainty bounds are obtained.</jats:p>

Digital Twin Science of Metal Powder Bed Fusion Additive Manufacturing: A Selective Review of Simulations for Integrated Computational Materials Engineering and Science

“…This uncertainty of the mechanism is because the powder bed forms beneath other powder particles, making it challenging to observe the behavior of powder particles experimentally. The discrete element method (DEM) is a computer simulation method that can model the behaviors of such powders (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) , as it numerically analyzes the motion of each particle according to Newton's equation of motion and Euler's equation of motion by calculating the viscoelastic and frictional forces acting between the particles. This method has been developed in various studies of phenomena relevant to a massive number of particles, such as sediment flow, ball milling of powders, silo filling, powder mixing (72) , and the behavior of slag particles in submerged arc welding (73) .…”

“…First, the spreading behavior of powder particles during the raking process is simulated by the discrete element method (DEM) (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) , in which Newton's equation of motion and Euler's equations of motion for a rigid body for each particle are solved numerically to predict particle motion. Second, the heating of materials due to the beam-matter-interaction is computed.…”

Recent progress in 3D printing piezoelectric materials for biomedical applications

“…Some examples show mixtures of aluminum powder and nylon suitable for molds, mixtures of carbon fiber and nylon with extremely lightweight and strong mechanical properties, and a variety of mixed plastic materials and ceramic materials. In theory, any fusible powder can be used to make products or models, so the choice of powder material is one of the main advantages of SLS technology [79][80][81][82][83][84]. In previously reported work, nanocomposite powders for SLS were mixed in a solid-state shear milling reactor for pretreatment, which provides a strong shear force and improves the effects of pulverization, dispersion, and combination [85].…”

Influence of Antibacterial Coating and Mechanical and Chemical Treatment on the Surface Properties of PA12 Parts Manufactured with SLS and MJF Techniques in the Context of Medical Applications

“…These properties make polyamide more often used in medicine [ 43 ] and orthoses production [ 44 ]. The most common technologies used in the process of 3D printing parts from polyamide are fused deposition modeling (FDM) [ 45 ], selective laser sintering (SLS) [ 46 ], and multi jet fusion (MJF) [ 47 ].…”