Micron-scale Monte Carlo Simulations for Additive Manufacturing using Electron Beam

Abstract

The powder bed additive manufacturing process for metal 3D printing uses laser or electron beam as its energy source for selective melting. While simulation of laser beam has been extensively investigated, Electron Beam Melting has been less scrutinized. Electron energy deposition in the metal powder is subjected to the way in which electrons transport in matter; this is a complicated process to follow and to obtain its characteristics. Simulating variety of energy and flux will enable better optimization of the AM process. We describe a Monte Carlo method simulation designed to evaluate the feasibility and utility of generating realistic particle-scale, powder bed configurations to investigate the additive manufacturing process in metals. Of particular interest here is the Electron Bean Melting process, by which micron-sized titanium particles are heated to above the melting point by a selectively directed electron beam. To this end full simulation details were introduced into the EGS5 Monte Carlo code, a general-purpose electron and photon transport program. A titanium solid body of a 50-micron radius in front of a wide beam at 60keV kinetic energy was defined. Energy deposition into the body, scattered electron energy, and angular distribution were then tallied. In addition, several visual electron-track analyses were demonstrated. From these simulations a new perspective of additive manufacturing process was attained, and a momentum transfer from electron to metal bodies formulated.