This presentation will focus on the DOE that Spirit AeroSystems completed at Sciaky Inc. The approach of this DOE was to show that operating pressure, the temperature, size/geometry of the melt pool and time at temperature are the major causes of the aluminum loss. Of the above factors, we could only directly measure the operating pressure. Therefore efforts were initiated to gain fundamental understanding of factors that we believed could be affecting melt pool geometry and the time above liquidous temperature. A look at the vapor pressure curves of aluminum, titanium, vanadium, and Ti 6Al-4V will be considered, as well as the coupling of temperature and pressure which places the molten metal above the vapor pressure of this alloy causing aluminum burn-off. 

To gain a better understanding of the impact of power and energy on melt pool geometry, different power settings were applied to alpha-beta forged base plates for different time spans. The test was performed to form both spots and lines, with and without the addition of wire. The information obtained will be used to develop controls to eliminate or reduce the aluminum burn-off and to validate finite element models.