Example safety mechanisms for example printing apparatuses are provided. An example printing apparatus may include at least one linear guide disposed on a first surface of a back-spine section of a printer body and a top chassis portion coupled to the at least one linear guide. In some examples, the top chassis portion may include a laser safety casing. In some examples, the laser safety casing may comprise a laser module configured to emit a laser beam along a laser path and a safety cover that is moveable to a first cover position intersecting the laser path.