# Wear Behavior of Uncoated and Coated Tools in Milling Operations of AMPCO (Cu-Be) Alloy
## 1 Introduction
The same authors conducted a similar study [43], studying tool wear mechanisms sustained during turning of the same copper-beryllium alloy, using a diamond turning tool. The authors found that the main wear mechanism experienced by the tool was amorphization of the diamond structure while machining the alloy. The high temperature generated in the tool-material interface, as seen in a previous study [42], and the interaction between hard particles of the alloy and the tool, caused vibrations during machining, which negatively impacted tool wear, and significantly increased the surface roughness of the machined material. The authors also conducted turning operations on pure copper, obtaining a significantly longer (60%) tool life. There have also been some studies carried out regarding the optimization of the machining process of these alloys, as in the study by [PERSON] et al. [44], where the optimal machining parameters for turning beryllium-copper alloy using a CBN and HSS tools were determined. The authors used the response surface methodology to design the experiments, then conducted an analysis of variance to optimize the process. The authors successfully determined the optimal values for cutting speed, feed rate, and depth of cut, to produce the best values regarding material removal rate and surface roughness. Another similar study, performed by [PERSON] et al. [45], also analyzed the influence of machining parameters in the material removal rate and produced surface roughness. Here, the authors considered three machining parameters, cutting speed, feed rate, and depth of cut. They used grey relational analysis and an analysis of variance to determine the most influential turning parameter in the mentioned outputs, concluding that the cutting speed was the most influential parameter, followed by the depth of cut and feed rate. The authors then performed experimental studies to validate this, determining in the end the optimal machining parameters to obtain the highest value of material removal rate. There have also been some studies conducted on the optimization of end-milling operations of copper-based alloys, such as those by [PERSON] [46; 47]. [PERSON] et al. [48; 49] evaluated the influence of machining parameters on process sustainability and stability, effectively determining the optimal machining parameters to obtain the least amount of energy consumption and vibrations that are developed during machining. It was found that the most influential parameter on both factors is spindle speed, being followed by feed rate. Regarding the analysis of the wear mechanisms that were developed during the milling of copper-beryllium alloys, although research in this matter is quite sparse, [PERSON] et al. [48; 49] conducted some studies in this regard, testing different cutting speeds and evaluating the influence of this parameter on the wear behavior of uncoated and TiAlN-coated tools. The authors found that the main wear mechanism that is developed is adhesive wear, which is responsible for most of the flank wear registered in the tools. Furthermore, this adhesive wear promotes abrasion, further decreasing the tools' life and negatively impacting the produced surface roughness. The authors also reported the formation of an adhesive layer of material on the tool's surface, directly correlated with the wear registered on the flank's surface. It was also registered that the cutting temperature developed during machining greatly promoted adhesive wear on the tool's surface, causing notch wear and chipping of the tool [48]. Studies such as the ones presented in the previous paragraph provide valuable information that can be used to optimize the machining of copper-beryllium alloys, as this is still a subject that is not widely explored. Moreover, there is a clear gap in the literature about the study of the wear mechanisms involved in the machining of copper-beryllium alloys and coated tools in general.