Because of the risks associated with exposure to metallic particles, efforts are being put into controlling and reducing them during the metal working process. Recent works have presented the methods and results of experimental studies on the effects of cutting speeds, workpiece material and tool geometry on dust emission during dry machining. To limit dust emissions, we must understand under which conditions formed, and be able to predict it. In this work, dust emission mechanisms are identified and a model is proposed. The model includes the tool geometry, the worked material properties, the cutting conditions, and the chip segmentation is based on the energy approach combined with the micro-friction and the plastic deformation of the material. The model is validated using results from experiments during an orthogonal machining process. Good agreement was found with experimental results.