Low Cost, High Speed Stereovision for Spatter Tracking in Laser Powder Bed Fusion

Powder Bed Fusion Additive Manufacturing affords new design freedoms for metallic structures with complex geometries in high performance materials. The aerospace industry has identified the inherent benefits of AM not just in terms of shape creation but also with regard to producing replacement parts for an aging fleet of aircraft. However, for these parts to be deployed in flight-critical applications, the quality must be well established given the lack of flight heritage for the manufacturing process. As additive manufacturing is executed layerwise, opportunities exist to non-destructively verify the fabrication in situ with a qualify-as-you-go methodology. In this study, a pair of low cost, high speed cameras are integrated and synchronized together to provide stereovision in order to identify the size, speed, direction and age of spatter ejected from the laser melt pool. The driving hypothesis of the effort is that behavior of spatter can be reliably measured in order to determine the health of the laser process and ensure that spatter is not contaminating the build. Feasibility demonstrations are shown that describe how the measurements are made and characteristics calculated from the image data and how the data were verified with alternative measurements. Opportunities, future work and challenges are discussed.