Milling of WC-Co-hardmetals

由于其高弹性模量，与钢相比具有更高的硬度以及与陶瓷相比具有更高的韧性，因此烧结碳化物在金属成形中起着重要作用。如今，在许多情况下，这些部件都是使用时间和成本密集的磨料工艺生产的，并且由于原始边缘区域的损坏，它们通常是完成的。由于高硬度切削材料的不断发展，铣削可以被认为是一种替代方法。迄今为止，烧结硬质合金的铣削研究仅在微切削领域进行，因此有关性能和工艺限制的重要科学问题尚未得到解决。虽然初步的研究表明，铣削烧结碳化物具有很高的潜力，但迄今为止，对运动学上较简单的刨/开槽工艺进行了基础研究。然而，材料、工艺参数和加工策略对切削力、刀具磨损和工件质量的影响还需要进一步的基础研究。现有的研究结果和申请人所做的初步工作表明，烧结碳化物的铣削潜力很大，尽管由于缺乏技术基础，该工艺几乎没有被考虑过。该研究项目的主要目标是对铣削烧结碳化物过程的理解做出根本性的贡献。这仅限于WC-Co碳化物的加工。重点研究了刀具，特别是切削刃的稳定性、工艺变量、加工策略和硬质合金对工件载荷依赖边缘区损伤的影响。为了更精确地理解切削机理和局部边缘区损伤，在一定的参数组合下进行了开槽实验，即线性切削运动。在实验结果的基础上，建立了描述硬质合金材料硬度对构件边缘区影响的经验模型。目的是预测作为未来加工任务的材料硬度的函数发生的边缘区损伤。此外，该模型使工艺设计，以铣削硬质合金组件所需的质量。最后，对烧结硬质合金的铣削性能进行了基本评价，并确定了工艺限制。生产部件的损伤随参数变化的深度被认为是研究项目的重要成果。它可以用于导出未来的处理策略，以尽量减少发生的边缘区损伤。

Due to their high modulus of elasticity, the significant higher hardness compared to steels as well as the higher toughness compared to ceramics sintered carbides play an important role in metal forming. Nowadays the components are in many cases produced using time- and cost-intensive abrasive processes and due to the originated edge zone damage they are often finished. As result of the progressing development of highly hard cutting materials milling can be considered an alternative. Research on milling of sintered carbides has until now only been conducted in the field of micro cutting, so that important scientific questions concerning performance and process limitations are currently unsolved. Until now the fundamental studies have been conducted especially for the kinematic simpler process of planing/ slotting, though the preliminary studies indicate that milling of sintered carbides offers a high potential. However further fundamental research on the influence of material, process parameters and processing strategies on cutting force, tool wear and work piece quality is required.The available results of the state of research and the preliminary work done by the applicant show the potential of milling of sintered carbides, though the process has been hardly considered for lack of technological fundaments. The main objective of this research project is a fundamental contribution to the understanding of the processes occurring during milling sintered carbides. This is restricted to the machining of WC-Co carbides. The study focuses on the investigations on the influence of the tool, especially the stabilization of the cutting edge, the process variables, the processing strategies and the carbide alloys on the load-dependant edge zone damage in the work piece. For receiving a more precise understanding of the cutting mechanism and the local edge zone damage slotting experiments, i.e. with linear cutting motion, are additionally conducted at certain parameter combinations.Based on the experimental findings an empirical model to describing the impact on the edge zone of the component as a function of the carbide alloy, i.e. the material hardness, is developed. The objective is to predict the occurring edge zone damage as a function of the material hardness for future machining tasks. Furthermore the model enables the process design in order to milling a carbide component in the required quality.In conclusion, a fundamental evaluation of performance as well as a determination of process limitations in milling of sintered carbides is carried out. The parameter-dependant depth of damage of the produced component is considered as a significant result of the research project. It can be used for deriving future processing strategies in order to minimize the occurring edge zone damage.