Strategies for Grinding of PCBN-Inserts

PcBN刀具在加工铁基材料和高温合金方面具有很高的潜力。根据应用的不同，对工具的要求也不同。这导致了PCBN规格的广泛变化。因此，PCBN刀具的磨削工艺设计是一个很高的挑战。通过端面磨削进行刀具的最终加工既耗时又耗费成本。砂轮相对于已加工材料的磨损量非常高。目前在IFW汉诺威的工作重点是主要工艺参数，如切割速度、进给速度和砂轮规格对砂轮磨损机理和材料分离机理的影响。这些研究表明，这些参数对磨损和材料分离有很大的影响。在磨削PCBN刀片时，根据PCBN规格和砂轮规格的不同，轮廓会磨损，但也会出现堵塞和变平。这会导致工具性能的降低。这些磨损机制可以通过主要工艺参数减少，但不能防止。为了改善砂轮的磨损性能，已知硬质合金刀具的磨削策略，如连续修整以及刀具振动和刀片倾斜。它们提供了保持刀具的切割性能的可能性。此外，它们还可以提高有关刃口切屑和表面粗糙度的质量。目前还没有关于这些策略的影响以及由此导致的砂轮磨损和PCBN镶件质量的知识。本项目的重点是在经验和半经验的基础上调查这些相互关系。此外，还将调查上述战略之间的相互作用。

PCBN cutting tools have a high potential regarding machining of iron based materials as well as superalloys. Depending on the application the demands on the tool differ. This leads to a broad variety of PCBN specifications. Due to this, the design of the grinding process of PCBN tools is a high challenge. The final machining of the tools via face grinding is time and cost consuming. The wear of the grinding wheel with respect to the amount of machined material is very high. The current work at IFW Hannover focuses on the influence of the primary process parameters such as cutting speed, feed speed and grinding wheel specification on the grinding wheel wear mechanism and the material separation mechanism. These investigations show that the wear as well as the material separation can be strongly influenced by theses parameters. While grinding the PCBN inserts, depending on the PCBN specification as well as grinding wheel specification, profile wear but also clogging and flattening occur. This leads to a reduction of the tool performance. These wear mechanisms can be reduced by the primary process parameters but they cannot be prevented. To improve the wear behaviour of the grinding wheel, strategies from grinding of cemented carbide tools, such as continuous dressing as well as tool oscillation and inclination of the insert, are known. They offer the possibility to maintain the cutting performance of the tool. Furthermore they enable an increase of the quality regarding cutting edge chipping and surface roughness. Currently there is no knowledge regarding the influence of these strategies and the resulting grinding wheel wear and the insert quality for PCBN available. This project focuses on the investigation of these interrelations on an empirical and semi-empirical basis. Furthermore the interaction of the mentioned strategies will be investigated.