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。这导致了各种各样的PCBN规格。因此，PCBN刀具的磨削工艺设计具有很高的挑战性。最后通过面磨加工刀具是费时又耗钱的。砂轮的磨损相对于加工材料的量是非常高的。IFW汉诺威目前的工作重点是研究切削速度、进给速度和砂轮规格等主要工艺参数对砂轮磨损机理和物料分离机理的影响。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，会发生齿形磨损、堵塞和扁化。这导致了刀具性能的降低。这些磨损机制可以通过主要工艺参数来减少，但无法避免。为了改善砂轮的磨损性能，硬质合金刀具的磨削策略，如连续修整、刀具振荡和刀片倾斜，都是已知的。它们提供了保持刀具切削性能的可能性。此外，它们可以提高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产生的砂轮磨损和PCBN的刀片质量的知识。这个项目的重点是在实证和半实证的基础上对这些相互关系进行调查。此外，将研究上述策略的相互作用。

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.