Fabrication of three-dimensional (3D) objects through direct deposition of functional materials using 3D printing equipment is called additive manufacturing (AM). Benefits of AM include producing goods quickly and on-demand, with greater customization and complexity and less material waste. While the use of AM has been growing, a number of challenges continue to impede its more widespread adoption, particularly in the areas of non-destructive evaluation/non-destructive testing (NDE/NDT) techniques for AM equipment health monitoring and measurement. In this paper, a PHM approach to AM equipment health monitoring, fault diagnosis and quality control is presented and illustrated with a case study. The presented PHM approach is developed using two types of NDE/NDT sensors: acoustic emission (AE) sensor and piezoelectric strain sensor. A seeded driving belt fault is used on a fused filament fabrication desktop 3D printer in the case study. The case study results have shown the effectiveness of the presented method for AM equipment fault diagnosis and quality control.