Process monitoring is essential for process repeatability and qualification, and for AM components can serve to help qualify the final parts themselves. For powder blown laser DED, mass flow is a crucial parameter whose measurement has proven to be particularly difficult, often with large errors. Similarly, current research approaches for defect detection in AM parts using optical, thermal, and acoustic monitoring have shown promise, but tend to be limited to qualitative assessments rather than quantitative ones. With these challenges in mind, we are working to develop a 3-mechanism sensing approach using coupled acoustic, capacitive, and inductive techniques with the goal of reducing mass flow measurement errors and eventually measuring the composition of mixed powder flows. We are also developing a magnetic computed tomography system for in-situ quantification of defects and their layer-by-layer evolution, including formation, migration, and annihilation. These sensors are also part of a greater DED process monitoring investigation.