Shape effects in binary mixtures of PA12 powder in additive manufacturing

TL;DR

This study investigates how particle shape affects powder spreading in additive manufacturing, revealing that spherical particles flow better and deposit further ahead, while irregular shapes hinder flow and cause temperature drops.

Contribution

The paper provides new insights into the influence of particle shape on flowability and temperature distribution in powder spreading for PA12 powders using DEM simulations.

Findings

Spherical particles exhibit better flowability and deposit further ahead.

Irregular particles hinder flow and cause temperature drops near the substrate.

Both shapes are homogeneously distributed in the deposited layer.

Abstract

The quality of the powder spread in additive manufacturing devices depends sensitively on the particles' shapes. Here, we study powder spreading for mixtures of spherical and irregularly shaped particles in Polyamide 12 powders. Using DEM simulations, including heat transfer, we find that spherical particles exhibit better flowability. Thus, the particles are deposited far ahead of the spreading blade. In contrast, a large fraction of non-spherical particles hinders the flow. Therefore, the cold particles are deposited near the front of the spreading blade. This results in a temperature drop of the deposited particles near the substrate, which cannot be seen with spherical particles. The particles of both shapes are homogeneously distributed in the deposited powder layer.