Laser powder bed fusion additive manufacturing in-process monitoring and optimization using thermionic emission detection

A system for performing laser powder bed fusion, comprising:

• an electronic controller;
• an optical light source controlled by the electronic controller to generate a beam having an output power level, the beam being sufficient in power to selectively laser melt a powder bed layer;
• a current measuring subsystem electrically coupled with at least one of an electrically conductive substrate on which the powder bed layer is deposited or with the powder bed layer deposited on the electrically conductive substrate, and in communication with the electronic controller, for detecting a current flow as at least one of the electrically conductive substrate or the powder bed layer is heated by the beam as the beam is scanned over the powder bed layer and as electrons are displaced by thermionic emission as the powder bed layer is heated by the optical light source, and generating a current flow signal in accordance with the detected current flow, the current flow signal being indicative of a temperature of at least one of the electrically conductive substrate or the powder bed layer;
• and
• the electronic controller configured to receive the current flow signal and to use the current flow signal to control a power level of the optical light source to ensure that a temperature of at least one of the electrically conductive substrate or the powder bed layer is at least one of above or below a desired temperature.