Manufacturing guy-at-large.

Build process simulation

Added on by Spencer Wright.

Early last year, Andrés Bellés Meseguer reached out to me with a proposition. He had read my piece in Metal AM magazine, and wanted to use my printed parts from DRT Medical Morris to verify a build process simulation workflow that he created using Abaqus. I agreed, and with Dave Bartosik's help I got him the build files necessary to simulate the print.

Andrés' full results were published in a paper titled Prediction of Distortion of a Titanium Bike Part Built by DMLS, which he presented at a NAFEMS conference in November. The simulation used a fine hexahedral mesh at the part itself, and a coarser mesh for the surrounding powder bed and the build platform. At each timestep, heat (representing energy applied by the laser) is applied to nodes throughout the model; it then dissipates throughout the structure. Below, see a thermal map of the part about 70 minutes into the build:

Image courtesy Andrés Bellés Meseguer and Prime Aerostructures

You can also use this simulation to model distortion in the part - seen here at the end of the build:

Image courtesy Andrés Bellés Meseguer and Prime Aerostructures

The distorted areas in the simulation correspond well to the as printed part, but Andrés notes that the magnitude values don't match perfectly; it's likely that some of the discrepancy can be narrowed by adjusting thermal coefficients.

This field - simulating additive processes to predict and compensate for built in stress and distortion - is one that I've been excited about since I began working with AM. Thanks to Andrés for sharing his work - I'm looking forward to more progress on this soon.