An AM process starts when shaping of material starts in a system. The process ends when the shaping ends. A process (or in-process) stage is preceded by a pre-process stage and followed by a post-process stage. A system can have material and information, but the process cannot start until the material starts to interact with process parameters. For example, an LPBF system can be filled up with powder and a digital file can be transferred to it, but the process will not start until a powder layer is spread. The spreading of the layer is due to an interaction between the material and the parameter. In an extrusion deposition system, when a filament does not start to melt after being fed, the process does not start. The filament melts due to material–parameter interaction. The process stops when the interaction stops. Stopping a process implies that shaping has stopped, but it does not imply that the processed material will no longer be processed. Though, further processing will not come within an in-process stage. After the stopping of the process, if a product formed is inadequate, post-processing is required.