Home / 3D Printing Processes / Researchers Develop a Geometry-based Model for Predicting Lack-of-Fusion Porosity in PBF

Researchers Develop a Geometry-based Model for Predicting Lack-of-Fusion Porosity in PBF

A study which appeared on the ScienceDirect Journal describes the development of a geometry based model for predicting lack of fusion during metal powder bed fusion processes (SLM, DMLS, EBM). The model relies on melt pool dimension, hatch spacing and layer thickness. The porosity (or density) predicted with the model agrees well with reported literature data on PBF processes.

The Carnegie Mellon University (located in Pittsburgh, PA) study was conducted by Ming Tang and P.Chris Pistorius (both from the Department of Materials Science and Engineering) and Jack L. Beuth, of the Department of Mechanical Engineering. In their research the scientists used a geometry-based simulation to predict porosity caused by insufficient overlap of melt pools (lack of fusion), a common and dire issue in powder bed fusion AM processes.

1-s2.0-S2214860416300471-fx1

The inputs into the simulation are hatch spacing, layer thickness, and melt pool cross-sectional area. Melt pool areas used in the simulations can be obtained from experiments, or estimated with the analytical Rosenthal equation. The necessary material constants, including absorptivity for laser-based melting, have been collated for alloy steels, aluminum alloys and titanium alloys.

Comparison with several data sets from the literature shows that the simulations correctly predict process conditions at which lack-of-fusion porosity becomes apparent, as well as the rate at which porosity increases with changes in process conditions such as beam speed, layer thickness and hatch spacing.

3D Printing Business Directory

About 3D Printing Media Network

3D Printing Media Network is the editorial branch of 3D Printing Business Directory. It was set up to provide the latest industry news and opinions to a global audience of professionals.

Check Also

Royal Adelaide Hospital Receives 3D Bioprinter Designed and Built at UOW to Work on Diabetes Cure

Share Tweet Share Buffer EmailIn an Australian first, researchers at the University of Wollongong (UOW) …