# Wear Behavior of Uncoated and Coated Tools in Milling Operations of AMPCO (Cu-Be) Alloy
## 1 Introduction
These coatings directly impact the wear behavior and performance of cutting tools [25], lowering the produced surface roughness, sustaining wear, and even decreasing the cutting forces that are generated during the process [26; 27]. One of these coating types that deserves some attention are diamond coatings used in machining as these significantly improve the wear behavior of cutting tools [28] and there have been some recent developments, further improving wear resistance by employing multilayered structures [29]. These directly improve the wear resistance of coatings, as the structure types confer the tool with properties such as improved thermal dissipation and improve crack propagation resistance, thus improving the overall tool's life and performance [30]. Still, regarding the wear performance of coated tools, the influence of the tool's substrate plays a significant role in the performance of a cutting tool. A poor substrate surface quality can produce defects during the deposition process that hinder the coated tool's performance, promoting premature coating wear [31]. The tool's substrate can also be improved, for example, by employing mechanical treatments before the deposition process [32]; these pretreatments are known to improve coating adhesion to a substrate, thus improving the wear behavior of the coating [33; 34]. There have been quite a number of advances in the deposition processes used to obtain coatings, mainly PVD (physical vapor deposition) [35], with some novel techniques, such as HiPIMS (high-power impulse magnetron sputtering), producing strong coatings with high deposition rates. The correct selection of deposition techniques is also important, as some coatings are more useful for finishing operations, such as PVD coatings, while the CVD (chemical vapor deposition) coatings are used more for roughing operations due to the average thicknesses obtained by these deposition techniques, and the residual stresses that are present in the deposited coatings [21; 22; 36]. In the case of PVD coatings, the compressive residual stresses greatly increase the cutting edge's strength, preventingpremature wear and chipping, while still retaining properties that are best suitable for finishing operations [37; 38]. Due to the increase in wear resistance conferred by deposited coatings, these can be applied to surfaces other than tools, such as injection models. These coatings directly increase the lifespan of injection molds, particularly in conditions that are subject to severe wear [39] or even in the case of glass fiber reinforced plastic injection, as these fibers contribute to the premature wear of these injection molds [40]. Coatings are also applied as means to improve the corrosion resistance of molds and mold inserts, as seen in the study by [PERSON] [41], where a coating of WC/C was applied to a copper-beryllium alloy used in the fabrication of injection molds. The author evaluated the corrosion and tribocorrosion behavior of the coating, comparing it to an uncoated sample of copper-beryllium alloy. It was found that the corrosion resistance of the coated substrate was higher than that of the uncoated one. It was also revealed that the wear resistance was also improved. This was not only due to the high hardness of the coating, but also the surface morphology of the coated surface, which showed a smooth and polished appearance, thus improving the tribocorrosion behavior. Regarding the machining of copper-beryllium alloys, there have been some recently performed studies conducted on this matter, with some interesting findings being reported, for example, in the study by [PERSON] et al. [42], where the authors investigated tool and hard particle interactions in nanoscale cutting of copper-beryllium. It was concluded that the crystallographic planes of the base material heavily influence the generated cutting forces, material deformation, and the tool's condition, offering insight on the cutting behavior of this material and its machinability.