A method for additively printing extension segments on workpieces using an additive manufacturing machine includes controlling, with a computing system, an operation of a print head of the machine such that a region of interest of a build plate of the machine is scanned with an electromagnetic radiation beam. Additionally, the method includes receiving, with the computing system, data associated with reflections of the beam off of the build plate as the region interest is scanned. Furthermore, the method includes receiving, with the computing system, data associated with a location of the beam relative to the build plate. Moreover, the method includes determining, with the computing system, a location of a workpiece interface based on the received data. In addition, the method includes controlling, with the computing system, the operation of the print head such that an extension segment is additively printed on the determined workpiece interface.