A method and apparatus for detecting machined substrate fragments by thermography. A heat source applies heat to a surface of machined component, the surface providing access to one or more internal chambers within an interior space of the component. The application of heat is sufficient in temperature and duration to cause a fragment temperature elevation rate in at least one machined substrate fragment present in at least one internal chamber that is greater than temperature elevation rate of the component. An IR detection device operably connected to a visual output device captures the IR signal from the component surface following the application of heat and outputs a thermal image of the component. Heat elevation points within the thermal image correspond with the presence of machined substrate fragments within at least one internal chamber of the component.