Tool Design And Performance Evaluation Of PCBN In Cutting Superalloys

Ni-based superalloys were applied in the areas of aerospace, watercraft,nuclear and petrochemical industry because of their elevated temperatureproperty. Cutting tool used in finish machining was carbide coated, however, toollife is too short for high cutting force and temperature, and there are no PCBNcutting tools for machining. In order to provide theoretical support and technicalguidance of PCBN in cutting superalloys the following researches were studiedby this paper.In order to cut down the experiment in tool design, this paper put forwardnew tool design method by studying PCBN characteristic and current methods. Innew one, all cutting styles are simplified continuation and interrupted grooving.Cutting infinitesimal will be generated on the base of experiment of grooving,then according to infinitesimal, tool geometry will be calculated. At last, new toolwill be tested. This one can reduce test coat, and meanwhile provide highprecision.Tool material, cutting edge and cutting angle are very important for PCBNtool performance. Firstly, the relationships were cleared between the types ofcutting edge and their parameters and cutting force, cutting temperature andresidual stress by Third wave AdvantEdge software. The result indicated thatchamfer width should smaller than0.35mm and chamfer angle should smallerthan35°. Secondly, different PCBN tools were tested in cutting superalloy. Inprophase of PCBN tool wear, notch wear on the trailing edge is in main position,while in anaphase, flank wear is dominant. PCBN with high CBN content andmetal bonding agent is suit for cutting superalloy. Lastly, Chamfer width isprimary factor for tool fracture in chamfer parameters. In tool geometry angles,cutting force is sensitive for enter angle. Flank angle is the main factor for affecting chip controlling of tool. And radial rake angle is dominant for toolfracture.In order to roundly and scientifically evaluated PCBN tool performance, anew evaluation system of PCBN in cutting superalloy was put forward byresearch current evaluation method and main index of estimating PCBN tool. Theprimary factor is that cutting tool can work normally, then the performance ofchip control and tool wear will be evaluated in the second step. In the next,according to working condition, different coefficient will be distributed tomachining quality, efficiency, economy, precision and their secondary indexes.The aggregative indicator of PCBN tool will be calculated finally as index ofevaluating tool performance. PCBN tool can be judged the adaptability ofmachining superalloys by performance evaluation of PCBN tools.