PVD-coating of electroplated cBN grinding tools to optimize the wear and application behavior when grinding nickel-based alloys

本计画旨在借由涂布涂层以降低研磨镍基合金时之砂轮磨损及提高材料移除率。由于其优异的高温强度、高疲劳强度和优异的耐腐蚀性，镍基合金被用于涡轮机和发动机等高科技领域。所需的低粗糙度表面通常只能通过磨削来制造。由于镍基合金的热、机械和化学性质，其磨削是困难的。减少砂轮磨损以及生成高质量表面和近表面完整性是挑战。磨削过程中砂轮与工件之间的摩擦会导致机械磨损，而摩擦产生的热量会加速化学磨损和热磨损。在砂轮上应用涂层是一种很有前途的方法，以满足上述挑战。通过使用涂层，摩擦将减小并且颗粒保持力将增加，由此通过减少电镀结合厚度可以获得更大的切屑空间。仍然缺乏对涂层工艺参数和工艺结果之间的相互依赖性的理解。在项目结束时，减少刀具磨损和摩擦，以及增加的芯片空间和相关的优化军事去除率时，磨削镍基合金与PVD涂层将实现。将开发一种PVD涂层，以增加磨粒保持力，并改善砂轮的摩擦学和非粘附性。由于所施加的PVD涂层的改进的电流结合特性，通过cBN晶粒的降低的结合水平将使芯片空间最大化。将检查应用不同PVD涂层和粘合剂水平的颗粒保持力。PVD涂层的优势将在镍基合金的高效深进给磨削中，在具有调整的切屑间距的涂层CBN砂轮与具有标准切屑间距的非涂层CBN砂轮的实验比较中得到验证。该项目的结果将是一个涂层砂轮与调整芯片空间和更大的空间冷却润滑剂和芯片的过程。因此，在高效深进给磨削镍基合金时，材料去除率和总材料去除率将增加，而不会对近表面层造成热损伤。砂轮的性能和加工效率将得到提高。

This project aims to decrease the grinding wheel wear and to increase the material removal rate when grinding nickel-based alloys by applying coatings. Due to their excellent high-temperature strength, high fatigue strength, and exceptional corrosion resistance, nickel-based alloys are used in high-tech areas such as in turbines and engines. The required surfaces with low roughness can often only be manufactured by grinding. Grinding nickel-based alloys is difficult because of their thermal, mechanical and chemical properties. The reduction of the grinding wheel wear as well as the generation of a high quality surface and near surface integrity are the challenges. The friction between grinding wheel and workpiece during the process leads to mechanical wear and the heat from friction accelerates the chemical and thermal wear. The application of coatings on grinding wheels is a promising method to meet the mentioned challenges. By using coatings, the friction will be reduced and the grain retention force will be increased, whereby a bigger chip space is possible via reduction of the galvanic bond thickness. There is still a lack in understanding the interdependencies between the coating process parameters and the process results. At the end of the project, a reduction of tool wear and friction as well as an increase of the chip space and the involved optimization of the martial removal rate when grinding nickel based alloys with PVD-coatings will be achieved. A PVD-coating will be developed that increases the grain holding forces and improves the tribological and non-adhesive properties of the grinding wheel. The chip space will be maximized by a reduced bond level of the cBN grains because of the improved galvanic bond properties of the applied PVD-coating. The grain retention forces applying different PVD-coatings and bond levels will be examined. The advantage of the PVD-coating will be validated in an experimental comparison of coated cBN-grinding wheels with adjusted chip space against non-coated cBN-grinding wheels with standard chip space at high efficiency deep feed grinding of nickel based alloys. The project result will be a coated grinding wheel with adjusted chip space and larger space for cooling lubricant and chips in process. As a consequence, the material removal rate and the total material removal when high efficiency deep feed grinding nickel-based alloys will be increased without thermal damage of the near surface layer. The grinding wheels’ performance and the efficiency of the process will be increased.