Metal Additive Manufacturing Conference 2019

Metal parts created by additive manufacturing are often difficult to dimensionally characterize due to the complex surface structures created by welding phenomena present in state-of the art printing machines. The most holistic techniques involve measuring the surface of each sintered layer of powder, however, this is complicated to perform in a non-contact, non-destructive, and in-situ manner. Techniques such as Spectral Domain Optical Coherence Tomography can be used to perform this task, but are limited to large pointwise measurement, limiting the speed and resolution of measuring the surface topography of each layer. In this work, we propose a method of layer-by-layer instantaneous area interrogation using a structured light system. We are presenting the design and measurement results of a low-cost fringe projection system to perform high resolution out-of-plane measurements on each build layer, and the quantification of small pores of sizes 0.050 mm and smaller. The measurement system proposed is purposefully selected to be small enough to allow for in-situ implementation inside a variety of different AM machines. Measurement results of the system are shown on test specimens dimensionally verified with lab-ordered profilometer measurements, presenting the validity of the structured light measurement system.