Review on the Productivity and Production Quality of WC-Co and Ceramic Tools Applied in Milling Operations of Inconel 718

Machining Inconel 718 remains a challenge for various industry sectors, causing high levels of tool wear only after a few minutes of machining, making it a hard to process material. Furthermore, Inconel 718 parts are crucial for sectors such as the aeronautical and aerospace, with these components being required to have high-quality and tight tolerances. This makes the machining of this alloy even more challenging, as guarantying these pre-requisites requires a high number of tool changes, ensuring that are always in good condition. To mitigate the problems associated with the machining of this alloy, many researchers and manufacturers use of coated tools, with the WC-Co tools still being widely used in this regard. However, since processing this alloy remains a challenge, there is a wide variety of studies focusing on finding even more solutions, by developing novel machining strategies, coatings and employing different tool materials. Lately there has been a focus on the study of ceramic tool materials to machine this alloy, as these materials exhibit high levels of hardness and wear resistance. Moreover, ceramic tools can be used at much higher cutting speeds than standard WC-Co tools, not only mitigating sustained wear, but also being more productive than their competitors. In the present review study, recent research papers were analysed, focusing on the milling of Inconel 718 using WC-Co tools and ceramic tool materials, particularly, SiAlON. The recent research trends and directions will be presented, as well as a comparison of the productivity and surface quality obtained with milling tools made of these tool materials. Regarding the comparison, the selected research studies focus on applications that can be replicated in industrial settings, thus facilitating this comparison. It was found that these ceramic tool materials show tremendous potential when applied to milling of Inconel 718, particularly for roughing operations, exhibiting material removal rates of up to ten times higher than standard WC-Co tools. However, the production quality is still not up to par with WC-Co tools.