This study has focused on chip-breaker design to break chips when machining inconel 718. For this purpose a dynamic chip breaker mechanism has been designed which can be used with positive and negative tool holders. Cutting speed, depth of cut and feed rate were selected as variables. A cemented carbide tool coated by PVD technique with two different layers (TiAlN-TiN) was selected as a cutting insert. Inconel 718 specimens were machined at f=0.10, 0.15, 0.20, 0.30 mm/dev feed rates, a=0.5, 1, 1.5, 2 mm dept of cuts and 30, 45, 60, 75 m/dak cutting speeds. Chip photographs were taken and surface roughness (Ra) values were measured. The results showed that chip breakability when machining inconel 718 was dependent on DC motor speed and chip breaker position on the cutting tool. The experimental results indicate that the designed chip breaker can break long chips when machining inconel 718 using the cutting parameters employed in this study. Also acceptable surface quality was achieved when machining Inconel 718 with dynamic chip breaker. In addition to this, depending on the cutting conditions, use of dynamic chip breaker on the surface of cutting insert exhibited cooling effect between 1% to 44%.