Experimental Study on the Effect of Cutting Tool Geometry in Micro-Milling of Inconel 718

In this study, the effect of tool geometry on the cutting forces, surface roughness, and burr formation in the micro-milling process is investigated. Three different geometric parameters (helix angle, number of cutting edges, and axial rake angle) that may affect the machining performance are taken into account. Inconel 718 superalloy was used as workpiece material, and the tests were performed under dry cutting conditions. According to the results obtained, the minimum cutting forces were obtained at a helix angle of 45 degrees. The increase in the helix angle causes the forces in the F-z direction to increase. For the new cutting tool, increasing number of cutting edges and axial rake angle has little effect on cutting forces. For the worn tool, the cutting forces are lower in the four-edges cutting tool, and the cutting forces obtained in the negative axial rake angle are also higher. The dominant damage types in the cutting tool are abrasive wear and chipping. Increased cutting distance causes the edge and corner radii of the tool to increase. As a result, cutting forces, surface roughness, and burr formation also increase. Generally, the maximum top-burr width is obtained on the up-milling side for the new cutting tool. Maximum top-burr width occurs on the down-milling side in the worn tools. Increasing helix angle causes burr width to increase. It has been determined that low number of cutting edge and negative rake angle cause smaller burr width.