Cutting edge preparation of ultra-hard cutting materials

切削刀具的性能在很大程度上取决于切削刃的微观几何形状。为了生产特定的切削刃微几何形状，工业上主要使用机械工艺。关于超硬切削材料，例如多晶金刚石（PCD）和多晶立方氮化硼（PCBN），这些机械加工在生产率、发生的磨损和相关的加工可靠性方面越来越达到其极限。因此，在DFG项目“Schneidkantenmikropräparation hochharter Schneidstoffe”的范围内，正在研究激光烧蚀在PCBN刀具上生成切削刃微几何形状的适用性。该项目的范围是了解激光能量输入引起的切削材料性能变化，这些变化取决于工艺参数以及切削材料成分（PCBN含量和粘合剂），并得出用于生产对称和非对称切削刃微几何形状的合适工艺策略。在正在进行的工作中已经证明，激光加工对切割材料的性能（表面质量、化学成分、硬度、残余应力）有很大的影响。初步研究结果还表明，刀具的切削性能在很大程度上受到激光加工所产生的切削材料的性质变化的影响。拟议的继续项目的目的是了解PCBN刀具的激光加工对其操作行为的影响。首先，通过实验和仿真相结合的方法确定了圆PCBN刀具切削楔中的机械应力。这为评价激光切削刃微预处理对PCBN刀具承载能力和耐磨性的影响提供了依据。特别是，在各种应用中的初始工具故障（切削刃突破）和连续磨损形式（后刀面磨损，火山口磨损）的机制进行了实验研究。本研究的目的是将由此产生的磨损机制与激光加工引起的刀具性能联系起来。最后，PCBN刀具的性能提高，证明了激光制备使用优化调整的激光工艺策略。

The performance of cutting tools is largely determined by the cutting edge microgeometry. For the production of specific cutting edge microgeometries, mechanical processes are mostly used in industry. Regarding super hard cutting materials such as polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PCBN), these mechanical processes increasingly reach their limits with regard to productivity, occurring wear and the associated process reliability. For this reason, within the scope of the DFG project "Schneidkantenmikropräparation hochharter Schneidstoffe", laser ablation is being investigated concerning the suitability for the generation of cutting edge micro-geometries on PCBN tools. The scope of the project is to understand the changes in the properties of the cutting material induced by the laser energy input in dependence of the process parameters as well as the cutting material composition (PCBN content and binder) and to derive suitable process strategies for producing symmetrical and asymmetrical cutting edge microgeometries. It has already been proven in the course of the ongoing work that the cutting material properties (surface quality, chemical composition, hardness, residual stress) are significantly influenced by the laser process. Initial findings also show that the tool cutting performance is largely influenced by the changes in the properties of the cutting material resulting from the laser process. The aim of the proposed continuation project is the knowledge of the influence of laser processing of PCBN tools on their operational behavior. First, the mechanical stresses in the cutting wedge of rounded PCBN tools are determined by a combined approach of experiment and simulation. This serves as a basis for evaluating the impact of laser cutting edge micro-preparation on the load capacity and wear resistance of PCBN tools. In particular, mechanisms of initial tool failure (cutting edge breakouts) and continuous wear forms (flank wear, crater wear) are experimentally investigated in various applications. The aim of this research is to link the resulting wear mechanism to the cutting tool properties induced by laser machining. Finally, the performance increase of PCBN tools is demonstrated by laser preparation using optimally adjusted laser process strategies.